common channel signalling mtp sccp tc_nsn 2g

GSM/EDGE BSS, Rel. RG20(BSS), Operating Documentation, Issue 05

Common Channel Signalling (MTP, SCCP and TC)

DN98785195

Issue 11-0

Confidential

2 DN98785195Issue 11-0


Id:0900d805807e0c4eConfidential

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Table of contentsThis document has 138 pages.

Summary of changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1 SS7 signalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.1 SS7 signalling network concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.2 SS7 signalling configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121.3 SS7 signalling hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2 SS7 network planning principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3 SS7 network structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.1 MTP level signalling network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.2 SCCP level signalling network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4 Creating MTP configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354.1 Activating MTP configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394.2 Setting MTP level signalling traffic load sharing . . . . . . . . . . . . . . . . . . 404.3 Creating large capacity signalling link . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5 Creating SCCP configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 445.1 Activating SCCP configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

6 Optimising MTP configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486.1 Modifying MTP level 3 signalling parameters . . . . . . . . . . . . . . . . . . . . 486.2 Modifying SS7 signalling network parameters . . . . . . . . . . . . . . . . . . . . 486.3 Modifying the values of signalling link parameter set. . . . . . . . . . . . . . . 496.4 Creating new signalling link parameter set . . . . . . . . . . . . . . . . . . . . . . 506.5 Modifying the values of signalling route set parameter set . . . . . . . . . . 516.6 Creating new signalling route set parameter set . . . . . . . . . . . . . . . . . . 526.7 Setting and modifying MTP level signalling traffic restrictions . . . . . . . . 536.8 Modifying MTP level signalling traffic load sharing . . . . . . . . . . . . . . . . 546.9 Using the signalling link set of another signalling network. . . . . . . . . . . 556.10 Removing MTP signalling point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 576.11 Moving a BSC under another MSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

7 Optimising SCCP configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 627.1 Modifying SCCP signalling point parameter set. . . . . . . . . . . . . . . . . . . 627.2 Creating new SCCP signalling point parameter set. . . . . . . . . . . . . . . . 627.3 Defining SCCP signalling point and/or subsystem to own signalling point

647.4 Removing SCCP signalling point and/or subsystem from own signalling

point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657.5 Modifying the values of SCCP subsystem parameter set . . . . . . . . . . . 667.6 Creating new SCCP subsystem parameter set . . . . . . . . . . . . . . . . . . . 677.7 Setting and modifying broadcasts of local SCCP subsystem . . . . . . . . 68

8 Monitoring signalling network objects . . . . . . . . . . . . . . . . . . . . . . . . . . 708.1 Interrogating SS7 network configuration and signalling route set state . 708.2 Interrogating and modifying signalling route state . . . . . . . . . . . . . . . . . 708.3 Interrogating signalling link set state . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

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8.4 Interrogating and modifying signalling link state . . . . . . . . . . . . . . . . . . . 718.5 Interrogating MTP level load sharing and MTP level STP traffic restrictions

718.6 Interrogating and modifying SCCP signalling point state . . . . . . . . . . . . 728.7 Interrogating and modifying SCCP subsystem state . . . . . . . . . . . . . . . 728.8 Interrogating SCCP subsystem broadcast status . . . . . . . . . . . . . . . . . . 72

9 SS7 troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 749.1 Signalling link stays in state UA-INS. . . . . . . . . . . . . . . . . . . . . . . . . . . . 749.2 Failures in the signalling link terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . 759.3 Signalling route goes to or stays in state UA-INR. . . . . . . . . . . . . . . . . . 779.4 Signalling link fails occasionally or there is an unexpected reset of AS7 789.5 Signalling link is in state UA-INS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 789.6 Signalling link activation succeeds but traffic fails . . . . . . . . . . . . . . . . . 799.7 All MTP and SCCP level objects are in state available (AV) but location up-

date fails or mobile calls are cut frequently after 4.5 min . . . . . . . . . . . . 809.8 Global title translation fails although translation exists and the global trans-

lation result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809.9 State of all subsystems in the remote network element is unavailable (UA)

although MTP route set is in state available-executing (AV-EX) . . . . . . 839.10 Some remote subsystems do not recover after route set unavailability . 839.11 A signalling point parameter or a subsystem parameter does not take effect

as described . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 839.12 After updating DX software, the SCCP of own signalling point is in state un-

available (UA), although everything else is in state available (AV). . . . . 849.13 TC sends an abort message with error code 03 "Incorrect transaction por-

tion" to the received dialogue request. . . . . . . . . . . . . . . . . . . . . . . . . . . 849.14 Large capacity signalling link creation or modification fails. . . . . . . . . . . 859.15 Allowing of link activation and initialisation of signalling terminal fail . . . 869.16 Activation of large capacity signalling link fails . . . . . . . . . . . . . . . . . . . . 869.17 Bit rates of the signalling links in the same link set. . . . . . . . . . . . . . . . . 87

10 States of SS7 signalling network objects . . . . . . . . . . . . . . . . . . . . . . . . 8910.1 States of signalling route sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8910.2 States of signalling routes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8910.3 States of signalling link sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9010.4 States of signalling links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9010.5 States of SCCP signalling points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9310.6 States of SCCP subsystems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

11 Error messages of MTP commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9611.1 MTP command major errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9611.2 MTP command minor errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

12 SS7 signalling network parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . 10812.1 MTP level 3 parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11012.2 SS7 signalling network parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . 11412.3 Signalling link parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11712.4 Signalling route set parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12612.5 SCCP signalling point parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

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12.6 SCCP subsystem parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

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List of figuresFigure 1 Example of two SEPs which transfer the signalling messages through two

STPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Figure 2 The functional parts of the Nokia signalling system . . . . . . . . . . . . . . . . 11Figure 3 Signalling between two network elements and the STP in between. . . . 11Figure 4 Example of a signalling point which belongs to three different signalling net-

works. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Figure 5 Example of TDM-based signalling links . . . . . . . . . . . . . . . . . . . . . . . . . 12Figure 6 The Transaction Capabilities scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . 13Figure 7 Signalling hardware used in different network elements. . . . . . . . . . . . . 14Figure 8 Basic mesh network structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Figure 9 Case A: Two out of four inter-STP link sets deleted . . . . . . . . . . . . . . . . 20Figure 10 Case B: Link sets between STPs of the same pair deleted . . . . . . . . . . 20Figure 11 Case C: All the four inter-STP link sets between STPs of the same pair de-

leted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Figure 12 The example network (STP = Signalling Transfer Point, SEP = Signalling

End Point) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Figure 13 Example of a message loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Figure 14 Example network of the scenario for one directional signalling . . . . . . . 23Figure 15 Example network of the possible negative consequences of using load

sharing between routes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Figure 16 Two network elements with different SCCP subsystems . . . . . . . . . . . . 30Figure 17 Example of SS7 SCCP routing and global title analysis in the case of loca-

tion update (LOC.UPD.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Figure 18 The points where the global tile translation is made (GTT 1–5) . . . . . . . 32Figure 19 The parts of the global title used in different global title translations . . . 32Figure 20 Example network where one network element belongs to two signalling

networks (NA0 and NA1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56Figure 21 Example network, where BSC2 is moved under MSC2 . . . . . . . . . . . . . 60

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List of tablesTable 1 The services, their recommended names and parameter values given in

the NPC command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Table 2 States of the signalling routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89Table 3 States of the signalling links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90Table 4 States of SCCP signalling points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93Table 5 States of SCCP subsystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94Table 6 Parameter levels, affected parts and the MML commands to handle them

108Table 7 Signalling levels and their predefined parameter sets . . . . . . . . . . . . 109Table 8 Parameter files and their contents . . . . . . . . . . . . . . . . . . . . . . . . . . . 110Table 9 MTP level 3 parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111Table 10 CCS7 signalling network-specific parameters . . . . . . . . . . . . . . . . . . 114Table 11 Signalling link parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118Table 12 Signalling route set parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127Table 13 SCCP signalling point parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . 132Table 14 SCCP subsystem parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

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Common Channel Signalling (MTP, SCCP and TC) Summary of changes

Id:0900d805807e3583Confidential

Summary of changesChanges between document issues are cumulative. Therefore, the latest document issue contains all changes made to previous issues.

Changes made between issues 11-0 and 10-1The following parameters have been added to chapter SS7 signalling network parame-ters:

• TETRA_LINK_FAILURE_DELAY • M3UA_PSTN_IMPLICATION • SOR_REF_WITH_NODE_INFO • GT_RES_SPEC_HDL_RI_SSN

Replace NEMU functionality as NE maintenance functionality in chapter SS7 network structures.

Changes made between issues 10-1 and 10-0A note and a comparable step have been added to procedure Moving a BSC under another MSC to say that a system restart is required for the changes to take effect. The example which follows the procedure has been updated accordingly.

Changes made between issues 10–0 and 9-0New AS7 variant, AS7-D has been added.

Changes made between issues 9–0 and 8-0Information on SCCP load sharing has been updated.

The GT_ADDR_FIXED_LEN parameter has been added to Section SCCP signalling point parameters.

The TC_PROTOCOL_VERS_EXCLUDED has been added to Section SCCP subsys-tem parameters.

Changes made between issues 8-1 and 8-0Removed the term 'optional feature' in relation to large capacity links as they can be con-figured without any optional software to Nokia BSCs.

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SS7 signalling

1 SS7 signallingSignalling is any transfer of data that enables speech and data connections between users. SS7 signalling has become the primary mode for signalling and information transfer in wireless and wireline networks. Information elements like calling party number, routing information related to 800 numbers, and current location information for roaming wireless subscriber are all carried over the SS7 signalling networks.

In the Public Switched Telephone Network (PSTN), signalling is needed for call estab-lishing, call release, and call maintaining. In the wireless system, signalling can also be independent from speech. The different functions of signalling are call control, control of services, and charging control. Wireless networks have some special functions, such as location update, handover, subscriber administration, and short message service.

It is also possible to use SS7 signalling for non-call-related signalling. In wireless systems, this feature is needed because the system has functions that are not con-nected to calls (for example, location updates and short message service). Furthermore, you can route signalling differently than in the case of a related call.

SS7 signalling also provides signalling error message handling. Error detection is done by including and interpreting a checksum within the message.

1.1 SS7 signalling network conceptsSignalling Point (SP), Signalling Transfer Point (STP), and Signalling End Point (SEP)A Signalling Point (SP) is a network element which sends and receives signalling mes-sages. A network element can also operate as a Signalling Transfer Point (STP), which means that signalling traffic goes through the signalling transfer point towards the des-tination signalling point. There can be several signalling transfer points between two Sig-nalling End Points (SEP).

Figure 1 Example of two SEPs which transfer the signalling messages through two STPs

The implementation of a signalling system in a Nokia network element consists of differ-ent functional parts. The main idea is that all functional parts offer their services to the other parts. In FigureThe functional parts of the Nokia signalling system, the functional parts that are under some other part serve the part above. For example, the Operations, Maintenance and Administration Part (OMAP) uses the services of the Transaction Capabilities (TC), the TC uses the services provided by the Signalling Connection Control Part (SCCP), and the SCCP uses the services of the Message Transfer Part (MTP).

SEP SEPSTP STP

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Common Channel Signalling (MTP, SCCP and TC) SS7 signalling


Figure 2 The functional parts of the Nokia signalling system

Not all parts exist necessarily in every network element. A signalling transfer point does not need to have all the functional parts that signalling end points have. Two different network elements can exchange SS7 signalling even when only the minimum configu-ration exists in both elements.

For example, if network element A has MAP and operates with network element B, then both elements must have a MAP, a TC, an SCCP, and MTP configuration, but in the STP between A and B there can only be an MTP, or an MTP, and an SCCP configura-tion.

Figure 3 Signalling between two network elements and the STP in between

Signalling network and Signalling Point Code (SPC)A network element can operate in a maximum of four signalling networks. Every network element has a signalling point code in every network it belongs to. The SPC (the number given to the signalling point) itself can be the same in each network. The following is an example where one network element belongs to three signalling networks. In the example, there is a different signalling point code for each network.

OMAPBSSAP

SCCP

TUP/ISUP/PUP/PUPX

INAP

MAP

TC

MTP

Network element A Signalling transfer point Network element B

TC

SCCP

MTP

SCCP

MTP

TC

SCCP

MTP

MAP MAP

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SS7 signalling

Figure 4 Example of a signalling point which belongs to three different signalling networks

Signalling linkSignalling points are connected together with PCM circuits. One PCM has 32 time slots (TSL). Each signalling link reserves one time slot from one PCM.

Figure 5 Example of TDM-based signalling links

1.2 SS7 signalling configurations

Message Transfer Part (MTP)The Message Transfer Part can be divided into three levels:

• Signalling Data Link level (level 1) defines the physical, electrical, and functional characteristics and the physical interface towards the transmission media.

• Signalling Link level (level 2) defines the functions considering message transfer between two adjacent network elements through a signalling link. It defines the message structure, framing, error detection and correction, alignment procedures, and so on.

• Signalling Network level (level 3) can be divided into two parts: message handling, which includes message routing and distribution to the respective user part, and network management, which provides all the necessary procedures for using the signalling network in an optimal way.

NA1IN0

NA0

IN0:SP=

80122

NA1:SP=80001

IN0:SP=80125

NA0:SP=80101

NA1:SP=

80005

NA0:SP=

80105

PCM=75, TSL=1

PCM=77, TSL=1

NA1:SP=

80115

NA1:SP=

80125

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When configuring and using MTP in a Nokia network element, you do not need to rec-ognise the levels at all.

Signalling Connection Control Part (SCCP)The Signalling Connection Control Part provides two different services, the connection-oriented and the connectionless services for other applications. The SCCP itself uses the MTP as a service.

The connection-oriented network service is used for virtual connections between network elements, and it provides the procedures for the establishment and release of those virtual connections.

The connectionless network service enables non-call-related communication between network elements which have to exchange information only for short periods. Furthermore, the connectionless service provides a global title translation function, which enables communication with network elements in other signalling networks.

For example, in the MSC/HLR the Mobile Application Part (MAP) uses the connection-less service of the SCCP, and Base Station Application Part (BSSAP) uses the connec-tion-oriented service of the SCCP.

Transaction Capabilities (TC)The purpose of Transaction Capabilities (TC) is to offer logical connections, that is, transactions, to TC users. These transactions are used to transfer the components by which the TC conveys a request to perform an operation, or a reply, between two TC users situated in different network elements. A TC user can access the network services of the signalling system through the TC. From the point of view of network services, the TC is a direct tube between a TC user and the SCCP.

The TC protocol is implemented in the Nokia network element through two different pro-cesses: one which complies with the ITU-T Q.771 - Q.775 Recommendations and another one which complies with the ANSI T1.114 Recommendation. The programs can operate in a network element simultaneously or individually.

The TC realises the services by using the network services provided by the SCCP in the common channel signalling system. Only the transfer mode using connectionless network services is specified for the TC. Both the segmenting and the non-segmenting SCCPs can be used.

The TC is part of the protocol but you do not have to configure it separately since the TC is used automatically when needed.

The use of the TC does not need any configuration or other actions.

Figure 6 The Transaction Capabilities scheme

SCCP

MAP INAP OMAP

ITU-T TC ANSI TC

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SS7 signalling

Operations, Maintenance and Administration Part (OMAP)The Operations, Maintenance and Administration Part (OMAP) is defined in the ITU-T Q.795, Q.750-Q755 Recommendation and in the ANSI T1.116 Recommendation. The OMAP makes it possible to set regular signalling network tests between specified sig-nalling points.

The MTP Routing Verification Test (MRVT) procedure has been implemented in the Nokia network element. This makes it possible to check if message routing functions properly in the signalling points. In the MRVT procedure, the system sends test messages to a destination signalling point by using different signalling routes. The test messages can pass through Signalling Transfer Points (STPs). A test is conducted suc-cessfully if replies to the sent messages are received within the specified time. If the test fails, the system produces a report that explains the reason for the failure.

1.3 SS7 signalling hardwareThe hardware used by signalling consists of signalling units, signalling link terminals, and Common Channel Signalling Management Units. Signalling units take care of the actual signalling, which is then transmitted to the trunk circuits by the signalling link ter-minals.

Signalling unitA signalling unit depends on the type of the network element. On a fixed network element (PSTN), the Common Channel Signalling Unit (CCSU) is used as the signalling unit. The signalling unit of a DX MSC is a CCSU unit in the fixed network direction and a Base Station Signalling Unit (BSU) in the direction of the Base Station Controller (BSC). The signalling unit used by the Base Station Controller (BSC) is a Base Station Controller Signalling Unit (BCSU).

Figure 7 Signalling hardware used in different network elements

Signalling link terminalA signalling link terminal is an entity composed of hardware and software, and it imple-ments MTP level 2 functions. There are several types of signalling link terminals avail-able: they are the different variants of AS7 plug-in units. There are different types of AS7

PSTN

CCSU

CCMU

HLR

CCSU

CCMU

BSC

BCSU

MCMU

MSC

CCSU

CCMU

BSU

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variants of DMC-bus and PCI-bus-based network elements. AS7 types with large capacity (for example, AS7–V, AS7–A, AS7–C and AS7–D) also support large capacity links Signalling link terminals are linked to the signalling unit, and there can be several terminals per unit.

Common Channel Signalling Management Unit (CCMU)There are two different common channel signalling management units used in different Nokia network elements. The Common Channel Signalling Management Unit (CCMU) is used in fixed switching (PSTN) and mobile switching (MSC/HLR) network elements and the Marker and Cellular Management Unit (MCMU) is used in the Base Station Con-troller (BSC).

Small network elements do not necessarily need a separate CCMU, but the tasks can be divided between the Central Memory (CM) and the Statistical Unit (STU). In small network elements, the management data on the common channel signalling can be stored in the central memory.

The CCMU implements the functions of the Message Transfer Part (MTP) and the Sig-nalling Connection Control Part (SCCP) in the CCS signalling network of the Nokia system built in accordance with the ITU-T specifications concerning signalling system number 7.

The CCMU is backed up with a spare unit that is in hot stand-by mode, so that the changeover to the spare unit does not disturb the functions of the other parts in the sig-nalling network.

Common Channel Signalling Unit (CCSU)There are two different common channel signalling units used in different Nokia network elements. The Common Channel Signalling Unit (CCSU) is used in fixed switching (PSTN) and mobile switching (MSC/HLR) network elements and the Marker and Cellular Management Unit (MCMU) is used in the base station controller (BSC). Small network elements do not necessarily need a separate CCMU, but the tasks can be devided between the Central Memory (CM) and the Statistical Unit (STU). In small network elements, the management data on common channel signalling can be stored in the central memory.

Base Station Signalling Unit (BSU)The BSU controls mobile and base station signalling (Base Station System Applcation Part, BSSAP), takes care of the decentralised functions of the Message Transfer Part (MTP) and the Signalling Connection Control Part (SCCP) of the signalling system, and is responsible for handling the signalling messages and functions related to the signal-ling channels connected to it.

The BSU is backed up by using the N+1 method, which means that several BSUs can be linked to the same back-up unit. In fault situations, the spare unit takes over the tasks of the failing unit.

Base Station Controller Signalling Unit (BCSU)The BCSU implements the functions of the Message Transfer Part (MTP) and the Sig-nalling Connection Control Part (SCCP) in the CCS signalling network of the Nokia system built in accordance with the ITU-T specifications concerning signalling system number 7. It also implements the needed signalling functions towards the Base Station (BTS).

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SS7 signalling

Central memory (CM)The main memory is a unit in the control part of the Nokia network element. The main memory (of the microcomputer) stores the subscriber data, charging and billing data, signalling data, and configuration data of the network element as semi-permanent files.

DN98785195 17

Common Channel Signalling (MTP, SCCP and TC) SS7 network planning principles

Id:0900d8058026efabConfidential

2 SS7 network planning principlesTo plan a whole signalling network you need experience in telecommunications and pro-fessional knowledge about signalling systems.

Before the SS7 configuration is created, the whole signalling network has to be planned carefully. The following issues must be defined before the SS7 signalling configuration is created:

• signalling point code allocation scheme from telecommunications administration, that is, the signalling point codes to be used in the own signalling network

• format of Signalling Point Code (SPC): length 14, 16, or 24 bits, and if the SPC should be allocated into subfields, for example, 3-8-3 bit or 8-8-8 bit format is neededFor more information, see ITU-T Q.708.

• physical transmission paths between different network elements • Signalling Link Code (SLC) and Time Slot (TSL) mapping to identify the signalling

links within a link set • type and amount of signalling traffic in order to define the link set size between two

network elements • any restrictions concerning other vendors' interconnecting network elements (if they

are compatible with, for example, the ITU-T, ANSI, or JAPAN specifications) • connection management and Circuit Supervision Messages (CCM) • network structure concerning Signalling End Points (SEP) and Signalling Transfer

Points (STP) • if there is a need for policing (screening) • if there is an SCCP network configured in the MTP network, and the requirements

are set • which are the network elements in the signalling network where the SCCP exists • what applications (SCCP subsystems) exist in different network elements and what

kind of addressing (GT or SPC and SSN) is used to send messages to them • what kind of global titles are used (for example, if roaming agreements and used IN

services affect global titles) • if there are any restrictions concerning timer values, address field of messages, or

management procedures for interconnected network elements made by other vendors

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SS7 network structures

3 SS7 network structuresThe signalling system can be used with different types of signalling network structures. The choice between the different types of signalling network structures may be influ-enced by factors, such as administrative aspects and the structure of the telecommuni-cation network to be served by the signalling system.

If the provision of the signalling system is planned on a per signalling relation basis, the result is a signalling network largely based on associated signalling, typically supple-mented by a limited degree of quasi-associated signalling for low volume signalling rela-tions. The structure of such a signalling network is mainly determined by the patterns of the signalling relations.

Another approach is to consider the signalling network as a common resource that should be planned according to the total needs of common channel signalling. The high capacity of digital signalling links in combination with the needs of redundancy for reli-ability typically leads to a signalling network based on a high degree of quasi-associated signalling with some provision for associated signalling for high volume signalling rela-tions. The latter approach to signalling network planning is more likely to allow exploita-tion of the potential of common channel signalling to support network features that require communication for purposes other than switching of connections.

The signalling network structures presented in this section is based on ITU–T Recom-mendations Q.705–Q.706, Blue Book.

Availability of the networkThe signalling network structure must be selected to meet the most stringent availability requirements of any user part served by a specific network. The availability of the indi-vidual components of the network (signalling links, signalling points, and signalling transfer points) must be considered in determining the network structure (for more infor-mation, see Recommendation Q.709).

Pay attention to the STP routing tables to ensure that circular routing does not occur.

Message transfer delayWhen structuring a particular signalling network, the overall number of signalling links (where there are a number of signalling relations in tandem) related to a particular user transaction (for example, to a specific call in the telephone application) should be con-sidered (for more information, see Recommendation Q.706).

There must be as few signalling transfer points as possible in the signalling network.

Signalling link loadWhen estimating the need for signalling links, it is recommended that one signalling link load should not overrun 0,2 Erl (Erlang is the unit of measure of the carried traffic inten-sity). In satellite links, the signalling link load should be under 0,06 Erl.

Message sequence controlFor all messages for the same transaction (for example, a telephone call), the MTP maintains the same routing if the connection remains functional, provided that the same signalling link selection code is used. However, a transaction does not necessarily have to use the same signalling route for both forward and backward messages.

DN98785195 19

Common Channel Signalling (MTP, SCCP and TC) SS7 network structures


Number of signalling links used in load sharingThe number of signalling links used to share the load of a given flow of signalling traffic typically depends on the following:

• the total traffic load • the availability of links • the required availability of the path between the two signalling points concerned • the bit rate of the signalling links

Load sharing requires at least two signalling links for all bit rates, but more links are nec-essary at lower bit rates.

When two links are used, each of them should be able to carry all the signalling traffic in case the other link fails.

Basic network structuresThis is an example of the basic mesh network structure and three simplified versions derived from it. More complex signalling networks can be built by using these models as building components.

Figure 8 Basic mesh network structure

In this example network, each signalling point with level 4 functions is connected by two link sets to two signalling transfer points. Each pair of signalling transfer points is con-nected to every other pair by four link sets. There is a link set between the two signalling transfer points in each pair. The simplified versions (A, B, and C cases) of the basic sig-nalling network are obtained by deleting the following, respectively:

• in the case of A, two out of the four inter-signalling transfer point link sets • in the case of B, the link sets between the signalling transfer points of the same pair • in the case of C, two out of the four inter-signalling transfer point link sets and the

link sets between signalling transfer points of the same pair

In connection with the availability of a given signalling link it is considered that the more signalling link sets are removed from the basic signalling network (going from the basic mesh network to the A, B, and C cases), the lower the availability of the signalling network is. However, an increase in the availability of the simplified signalling network may be attained by adding one or more parallel signalling links to each of the remaining signalling link sets.

SEP signalling end point

STP signalling transfer point

SEP

STP STP

SEP

STPSTP

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Figure 9 Case A: Two out of four inter-STP link sets deleted

Figure 10 Case B: Link sets between STPs of the same pair deleted

Figure 11 Case C: All the four inter-STP link sets between STPs of the same pair deleted







SEP

STP STP

SEP

STPSTP

SEP

STP STP

SEP

STPSTP

SEP SEP

STP STP

STPSTP

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3.1 MTP level signalling networkBasic structuresThe MTP gives you many possibilities to configure the network. It is possible to create up to eight signalling routes to each destination and these routes can work in load sharing mode or backup mode. Consider carefully whether it is necessary to use more than three routes because, in this case, the management of the whole network becomes very complex. The use of load sharing between signalling routes also needs careful planning because it affects the adjacent signalling points and their opportunities to use alternative routing. Typically, load sharing between signalling routes is used in Sig-nalling End Points (SEP) if it is used in the Signalling Transfer Points (STP). The risk of message loops increases especially in larger networks if the network topology has not been planned carefully.

When signalling routes are defined, it must be understood that the whole path across the network cannot be defined at the originating signalling point. Only the destination point and the adjacent signalling transfer point are defined. The adjacent STP further routes the messages according to its own routing rules. The message originator cannot determine it. For example, in Figure The example network (STP = Signalling Transfer Point, SEP = Signalling End Point), when the signalling routes from SP A to SP D are defined, SP A does not know how SP B is routing the messages originated from A further to D: either directly to D or through some STP X.

Figure 12 The example network (STP = Signalling Transfer Point, SEP = Signalling End Point)

MTP load sharingLoad sharing between signalling routes is defined when the signalling route set is created, and it can be modified afterwards with the NRB command. Route priority is important in load sharing (priority varies from 0 to 7; 7 is the highest priority). The route with the highest priority carries the traffic. If there are two or more routes with the same priority, they work with load sharing if it is allowed. If load sharing is denied, each priority must be defined only for one route because if the same priority is defined for several routes, it is not possible to know, which route becomes active (the route that becomes available first enters state AV-EX and the others enter state AV-SP). Within a link set,

STPB

STPC

SEPA

SEPD

STPX

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signalling traffic is always shared across all the available signalling links, so the priority of the signalling link has no effect there (according to Signalling Link Selection Field (SLS) values).

As a general rule, the highest priority is assigned to the direct route (the route using the link set which connects the originating signalling point to the destination signalling point) and the second highest priority is assigned to the route which is selected to be the primary alternative if the direct route fails, and so on. If there is no direct route (only routes through the STP), it is useful to choose the priorities so that the signalling rela-tions in both directions use the same path (Example 1). Otherwise, you may end up with one-direction-signalling (Example 2) which may cause more disturbance than no signal-ling at all.

Example: Scenario for message loop

Figure 13 Example of a message loop

Configuration in the example network:

• Route set from A to D: direct route with priority 7 and indirect route through STP B with priority 7.

• Route set from B to D: direct route with priority 7 and indirect route through STP C with priority 7, load sharing allowed.

• Route set from C to D: direct route with priority 7 and indirect route through STP A with priority 7, load sharing allowed.

Problem:

In a configuration, when a message comes to any of the STP points (A, B, C), the result is a message loop C – A – B – C –.... for certain parts of the traffic (messages with certain SLS codes).

STPC

SEPD

STPB

STPA

loopprior.=7

prior.=7

prior.=7

prior.=7

prior.=7prior.=7 STPC

SEPD

STPB

STPA

1) 2)

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Example: Scenario for one directional signalling

Figure 14 Example network of the scenario for one directional signalling


• Route set from A to D: direct route with priority 7 and indirect route through STP B with priority 6.

• Route set from D to A: direct route with priority 7 and indirect route through STP C with priority 6.

Problem:

If link set A-D fails, the SP A routes messages destined to D through B and the SP D routes messages destined to A through C. If link set C-D fails (or alternatively, SP C sends a transfer prohibited (TFP) message to SP D concerning SP A), link set A still routes messages destined to D through B, but D can no longer reach A.

STPC

STPB

STPA

STPC

STPB

STPA

1) 2)

prior.=7

prior.=7

prior.=6

prior.=6

SEPD

SEPD

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Example: Possible negative consequences of using load sharing between routes

Figure 15 Example network of the possible negative consequences of using load sharing between routes


• Route set from A to D: direct route with priority 7 and indirect route through STP B also with priority 7, load sharing mode allowed in the route set.

• Route set from D to A: direct route with priority 7 and indirect route through STP B with priority 7, load sharing mode allowed in the route set.

Problem:

This kind of configuration (stage 1) causes a short unnecessary break in the signalling traffic from B to D.

If link set B-D fails, STP B sends a TFP message (concerning D, stage 2) to STP A. After a forced rerouting (stage 3), SEP A sends a TFA message (concerning D, stage 4) to STP B, and then STP B can access SEP D.

MTP level STP traffic restrictionsWith the MTP level STP traffic restrictions, you can define how unauthorised STP messages are identified and how they are treated. Messages are either transferred further or destroyed. It is also possible to define if an alarm indication is set.

Administrators can make bilateral agreements on how to operate SS7 signalling between their networks. These agreements can replace restrictions on the SS7 messages authorised for one administrator to send to the other. Restrictions can be made, for example, because of network security or as a result of service restrictions. Unauthorised signalling traffic can be, for example, STP traffic for calls set up through networks other than the one containing the STP, which has not been agreed bilaterally.

An administrator making an agreement on restrictions can wish to identify and provide special treatment to unauthorised SS7 messages.

SEPD

STPB

STPA

1)

prior.=7

prior.=7

prior.=7 prior.=7

SEPD

STPB

STPA

2)

SEPD

STPB

STPA

3)

TFA(conc. D)

SEPD

STPB

STPA

4)

TFP(conc. D)

FR

DN98785195 25



Allocation of signalling point codesUsually, the national telecommunications authorities allocate a certain range of signal-ling point codes for each of you, and you can use those point codes within your own networks as you wish. It is also possible to use some other network indicators apart from the PSTN network within your own network and it enables to have more network elements connected (for example, in the GSM network BSCs are working in the NA1 network, while the signalling point codes of the NA0 network are allocated only for MSCs and HLRs).

You have to take into account the national instructions when allocating the signalling point codes in your signalling network.

Signalling parameters and parameter setsThere can be some network elements in the network which work according to some older specifications or which have some restrictions on their functions (for example, it is forbidden to send a Traffic Restart Allowed (TRA) message to an adjacent network ele-ment), and these cases must be examined before the network is configured. In a Nokia network element, it is possible to define parameters which are related to signalling network, signalling route sets, or signalling links. With proper settings, a Nokia network element is compatible with most network elements.

With the signalling parameters, it is possible to control and modify certain functions of the signalling network. The signalling parameters are divided into six different levels, depending on which part of the signalling system they affect.

For some levels it is possible to define a number of special parameter sets. The param-eter sets can be connected so that different parts of the signalling system use different parameter sets, that is, it is possible to use different kinds of signalling in different direc-tions.

For example, there can be two different signalling link parameter sets defined, one con-nected to the signalling links leading to network element X and another connected to the signalling links leading to network element Y. In this case, signalling functions are differ-ent towards network element X, than towards network element Y.

In the Nokia system there are some parameter sets predefined for different SS7 signal-ling standards (for example, ITU-T, ANSI, JAPAN). It is recommended to use these parameter sets or at least to start with them. If there is a need to change them, it is rea-sonable to create a new one on the basis of the predefined one.

Additional signalling point codesUsually, the national telecommunications authorities allocate a certain range of signal-ling point codes for each of you and you can use those point codes within your own network. Though you have to take into account the national restrictions when allocating the signalling point codes in your networks, it is possible to utilise some unused network indicators within your own networks. But even when this is not possible, there are usually free signalling point codes available to bring additional value to you. Nokia Siemens Networks has implemented the Additional Own Signalling Point Codes func-tionality designed to increase the signalling capacity between two (or more) network ele-ments.

The Additional Own Signalling Point Codes functionality is implemented on the MTP level. Since the functionality has not been implemented on the SCCP level, it offers only

26 DN98785195




limited value to applications using SCCP addresses in DPC format. But since very few applications are tied to using SCCP addresses in DPC format, the majority of SCCP users can benefit from the feature when routing their messages based on Global Title (as subsystem states, and so on, maintained by SCCP management have no effect). The fact that each additional own signalling point code occupies one out of the 1000 DPCs supported is also a real limitation to very few applications (if any).

The MTP level supports four different types of additional own signalling point codes: Reception Additional Point Code, User Part Additional Point Code, Interworking Function Additional Point Code, and Private View Additional Point Code. In the receiving direction, all the additional own signalling point code definitions above make the MTP recognise the concerned signalling point code as an address of the own network element. In the outgoing direction, each DPC can be connected to one additional own signalling point code, other than Reception Additional Point Code. Such definitions guide the MTP to replace the originating point codes of User Part messages sent towards the DPCs with the additional own signalling point codes.

There are also other types of signalling point codes which make the MTP alter the OPC field of signalling messages and which are connected to additional own signalling point codes: Test Routing Signalling Point Code, Management Cluster Signalling Point Code, and Inverted View Signalling Point Code. They have been designed to bring additional functionality to the operator networks, but not necessarily to increase signalling capacity between two (or more) network elements.

Additional own signalling point code operationThe four types of additional own signalling point codes that the Nokia Siemens Networks system supports have been designed to bring additional value as follows:

• User Part Additional Point Code makes it possible to create more than 4096 speech channels between two network elements.

• Interworking Function Additional Point Code makes it possible to create two (or more) signalling link sets between two network elements if the capacity of the 16 sig-nalling links is not enough.

• Private View Additional Point Code makes it possible to create more than 4096 speech channels and more than 16 signalling links between two network elements even if the partner NE offers nothing special to help in these respects.

• Reception Additional Point Code makes it possible to have the MTP share the load of signalling destined to the STP pair both (or all) of whose members deliver the messages to the appropriate User Parts for further actions (such as GT analyses).

Inverted view signalling point code operationFor example, in the SRRi the User Part keeps contacting the register which processes its database query and updates messages. If this register has an HLR as a backup NE, both members of the mated pair HLR have this processing capability but only one of them is active at a time. The active register which receives the User Part database update messages keeps its database up to date and transfers the updates to the redun-dant register through the NE maintenance functionality. The redundant register becomes active only when the connection between its pair and the SRRi is lost.

The mated pair HLR can recover from failure and can change the direction of register updates automatically. In order to support this, the MTP does not need to provide only the Reception type additional point code functionality, but also the Inverted View signal-ling route sets. In a redundant HLR the MTP notices from received signalling that the

DN98785195 27



connection between the active HLR and the SRRi is lost and indicates this knowledge to the signalling route states in the Inverted View signalling route set. The NE mainte-nance functionality keeps inquiring the states of objects related to the Inverted View sig-nalling route set from the MTP functionality, so it can make the previously redundant register active and can change the direction of register updates soon after the failure.

Management cluster operationThe signalling management cluster is an entity which consists of Signalling Gateway and Application Node but is visible to other network elements only with the Application Node signalling point identity. The MTP level 2 connections and other MTP functional-ities of a signalling management cluster are in the Signalling Gateway, while the User Part functionality of the cluster is in the Application Node. When the MTP of the Signal-ling Gateway receives a User Part message destined to the management cluster, it forwards the message to the Application Node.

The signalling management cluster is recommended when a signalling point becomes an Application Node as it is connected to a Signalling Gateway and, therefore, stripped of its MTP level 2 connections to other network elements. Then, other network elements need no configuration changes as they see nothing from the management cluster but the same old signalling point code. One practical example of transition from signalling points to signalling management clusters is the migration from Mobile Switching Services Centres to MSC Servers and Multimedia Gateways.

Loop signalling route conceptA network element can simulate several network elements by using Test Routing sig-nalling route sets. A Test Routing signalling route set consists of a direct route through a link set the messages of which are looped either physically or by a software. If the loop is physical, the route set is called L-LOOP and the signalling links in the direct route have to be in active state, whereas loop by software (T-LOOP) does not require concerned links to be in service. In a Test Routing route set like this, the signalling messages are transferred from one signalling unit to another along a message bus. You can select any free address from the signalling destination point range used by the signalling network and define it as the loop route point address. The number of loop signalling route sets is not restricted.

The loopback feature used by the TUP/ISUP needs two loop signalling route sets in call setup. The initial messages of a call are sent to the first loop signalling route set and the same message returns to the home network element with the point code of the other loop signalling route set as its originating point code. This gives the user an impression that the own point starts a call to the first point and the second point starts a call to the own point.

The loopback feature is activated and the type of the loop is chosen when the signalling route set is created with the commands of the NR command group.

Signalling cluster concept and partial routingIn the ANSI signalling network, several nodes of the same signalling network can be gathered from a cluster in MTP-level routing when the point codes of the nodes share the same initial part. The whole cluster is referred to with a point code, in which, after the same initial part, the rest consists only of zeros. The length of the common initial part can be 8 or 16 bits. The length of the signalling point code is 24 bits.

The ANSI signalling network can use a destination point that belongs to a cluster, so that the common routing regulations are determined for the members of the cluster. An STP

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network element of the MTP level can route forward a signalling message even if it does not identify the destination of the message, provided that the route to the cluster that includes the destination point has been given to the network element.

In the Nokia system, the cluster is divided into three parts. The clusters are categorised according to the restrictions based on their locations:

cluster E (end-point view of remote cluster) Cluster E is a collection of routes without priorities, on the basis of which the CCDESM transforms the received network management messages addressed to the whole cluster into messages addressed to the individual members of this cluster. Cluster E can only be accessed through STPs and the full point identifier of the members of the cluster must be known. The own point handles a cluster of type E without notifying its adjacent points of the changes in states concerning cluster E or the availability of the cluster. The adjacent points are notified of changes in the states and the availability of the individual members of the cluster. Clusters of type E can be created in the Signalling End Points (SEP) and in the Signalling Transfer Points (STP). The signalling route set to cluster E is created by creating a route through the actual own point of an STP pair to its alias point. Messages cannot be sent to the members of cluster E by means of partial routing.

cluster C (cluster of another STP) When partial routing is used, a signalling route set of cluster C must be created. In this case, there is no need to know the full signalling point code of an individual signalling point of a cluster, and messages can be sent to this signalling point, provided that cluster C is available. It is not allowed to determine any full signalling point codes of a signalling point that is a member of cluster C. Changes in states of cluster C that are determined in an STP are notified in the TCP and TCA messages.

cluster B (broadcast address of local cluster) Cluster B means that an own signalling point functions as one part of an STP pair and with its pair, recognises all the members of the cluster. A member of an STP pair notifies the availability of the cluster with TCP and TCA messages when the last member of the cluster becomes unavailable or when the first member of the cluster becomes available. If either member of the STP pair notices that it can no longer access any member of cluster B, it sends the adjacent points a TCP message concerning the cluster. This means that cluster B is not available for its adjacent points, even if the members of cluster B were available through another STP pair. A TCA message is sent when the STP pair that has sent the TCP message has accessed the first member of the cluster. However, the TCA message is sent even if one half of the pair did not access any of the members of the same cluster.

g The Nokia system does not support clusters of type B.

The signalling clusters are not shown to the user part, which is not notified of the changes in the states of clusters, either.

In the ANSI signalling network, the message routing software investigates first all the 24 bits in the initial part of the point code of the destination address. If the address is unknown, they investigate only the first 16 bits and, finally, only the first 8 bits. This kind of routing is called partial routing. If partial routing results in an address that does not

DN98785195 29



belong to any of the signalling cluster types, the address of that message is regarded as faulty.

Use of the link set of another networkIf there is a need to use more than one network indicator (for example, NA0 and NA1), and the signalling traffic in the other one is very low, it is possible to use the signalling link set of another network. This means that there is physically only one link set between two network elements but there are two route sets using that link set.

g Using the feature is possible only between two Nokia network elements.

Large capacity links The large capacity SS7 link feature provides more signalling capacity than conventional 64 kbit/s SS7 links. A large capacity link provides capacities from 64 kbit/s up to 1984 kbit/s.

When there is a need for a large amount of signalling capacity between two network ele-ments, it is difficult to manage it with the conventional 64 kbit/s signalling links. Only 16 signalling links can be created into a signalling link set. And only one link set per signal-ling network is allowed between two network elements. With this feature it is possible to create less signalling links which have larger capacity. It provides an easier way to handle large amounts of signalling capacity. For example, one 512 kbit/s link can replace eight conventional 64 kbit/s links.

A large capacity SS7 link uses more than one time slot, as in the conventional 64 kbit/s signalling link. The support for large capacity signalling links is implemented into AS7-V, AS7-VA, AS7-A, AS7-C and AS7-D types of signalling link terminals.

The functionality of the large capacity SS7 signalling link is the same as in the conven-tional 64 kbit/s links, but the capacity is larger. A large capacity signalling link is not com-patible with 64 kbit/s links, that is, both ends of a signalling link have to support large capacity signalling links. Signalling links with different capacities cannot be created into the same signalling link set or signalling route set.

g Using the feature is possible only between two Nokia network elements.

3.2 SCCP level signalling networkWhen you are planning the SCCP network, remember that the SCCP network is config-ured on the MTP network, and that there must be a route set on the MTP level to all Sig-nalling Points (SP) known by the SCCP.

The SCCP has to be configured locally in the network elements which have mobile appli-cations, IN applications, or which perform SCCP global title translations. The SCCP has to be configured also for those of the remote network elements to which SCCP messages are sent. The SCCP does not need to be configured in MTP level STP network elements if the SCCP messages are only sent through them and not to them.

Applications that use SCCP services are defined as subsystems which are identified by a Subsystem Number (SSN). The subsystems can be SCCP management (SCMG), MSC MAP, VLR MAP, HLR MAP, INAP, OMAP, and possibly some network-specific subsystems, like BSSAP.

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The SCMG is located in all signalling points that are known by the SCCP. The MSC MAP, VLR MAP, and BSSAP are located in MSC/VLRs and the HLR MAP can be found in HLRs. The INAP is located in IN SSPs and SCPs, but it can also be in MSCs.

How the subsystems are defined in the SCCP network depends on what kind of addresses are used in signalling message transfer.

SCCP addressing (GT or SPC/SSN)There are two different types of addresses which are used for routing in the SCCP. Routing can be based on the Signalling Point Code (SPC) and Subsystem Number (SSN) addresses, which means that the SCCP has to know all the signalling points and subsystems to which it can send messages because SCCP routing checks the status of the called SPC and SSN before sending a message to the MTP. Routing can also be based on the Global Title (GT). In this case, the SCCP needs to know much less about the network because it only checks the status of the signalling point to which a message is sent for the next Global Title Translation (GTT).

All local subsystems have to be defined for the SCCP because the SCCP checks their status before it passes incoming messages to them. The SCCP and SCMG subsystems have to be defined in remote nodes if any SCCP messages are sent to the SCCP. The subsystems to which the messages are sent with the SPC and SSN addresses also have to be defined in the remote nodes. This is the case with the A interface. In the MSC, all the BSSAPs in the BSCs have to be defined, and in the BSCs, the BSSAP of the MSC has to be defined. Elsewhere in a GSM network, it is always possible to use the GT for addressing. When roaming to or from another operator's network, the GT has to be used, but inside one operator's networks it is also possible to use the SPC and SSN.

For example, in Figure Two network elements with different SCCP subsystems, in network element A, the MAP application of B must be defined. In network element B, the MAP application of A must be defined. The INAP application of network element A does not necessarily need to be defined in network element B because there is no need for changing messages.

Figure 16 Two network elements with different SCCP subsystems

The GTs that have to be defined in a GSM network depend on the roaming agreements you make. How and where the translations have to be defined depends on the structure of the network.

For example, it is possible to have one or two gateway STPs that handle all the outgoing and incoming signalling traffic. In that case, all the GTs of outgoing messages are trans-

Network element A Network element B

TC

SCCP

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lated so that the messages are sent to those STPs for further translation. In the STPs, the outgoing GTs can be translated to international gateways or to other operator's gateway STPs.

Figure 17 Example of SS7 SCCP routing and global title analysis in the case of location update (LOC.UPD.)

This is what happens in each network element.

MSC1 Local BSC indicates a location update of a Mobile Station (MS). The MSC/VLR sends a location update message to the HLR. This message is sent as a UDT message and the GT of the called party address of the message is derived from the IMSI number of the MS. The country code part of the GT is translated in the MSC1 to find out the MTP address of the international gateway node and the message is sent to it.

PSTN1 PSTN1 transfers the messages through the MTP to PSTN2.

PSTN2 A UDT message is received from a national network. After a GT trans-lation where only the header information and country code of the called GT is translated, the message is passed to the international gateway of the destination network.

PSTNX PSTNX receives a UDT message from an international network and after the GT translation of the header information, country code, and operator code, it passes the message to the gateway MSC of the des-tination operator in the national network.

MSCY MSCY gets messages and makes a GT translation to find out the des-tination node of the message in your network.

HLRZ HLRZ makes the last GT translation (if it has not been done in the MSCY) to find out if the message is coming to it. The SCCP passes the UDT message to the local subsystem.

PSTNXIN0SP=1XNA0SP=X

HLRZNA0SP=Z

IN0

MSCYNA0SP=Y

DPC=102/NA0route=GT

DPC=1X/IN0route=GT

DPC=Y/NA0route=GT

DPC=Z/NA0route=GT

DPC=301/NA0route=GT

DPC=1102/IN0route=GT

DPC=X/NA0route=GT

DPC=Y/NA0route=GT

ATM Module

IN0

NA0 NA0

RNC

MSC1/VLRNA0SP=301H

PSTN1NA0SP=101H

PSTN2IN0SP=1102HNA0SP=102H

32 DN98785195




Figure 18 The points where the global tile translation is made (GTT 1–5)

Figure 19 The parts of the global title used in different global title translations

With an IN application, the first message is most often received from the local subsystem with an address including the GT. The rest of the signalling can use SPC and SSN addressing. If SPC and SSN addressing are used, the IN SSP has to know all the SCPs that it can use and vice versa, and the GT used by the IN subsystem is immediately translated to the SPC and SSN of the SCP subsystem. If the STP is used between the SSP and SCP, the GTT can lead to the STP and, if GTs are used for addressing throughout the signalling, the SSP does not need to know about the SCP and vice versa.

SCCP servicesThe SCCP has two different message handling services. The connectionless service is used for database inquires, for broadcast-like services, as well as for the passing of SCCP management messages. The connection-oriented service is currently used only between the MSC and the BSC for call signalling.

Needed SCCP subsystemsIn a local node, all the subsystems that are used have to be defined in the SCCP, which means that there always has to be an SCMG. The MSC needs the MSC MAP, VLR MAP, and BSSAP and in some cases also the INAP. In the HLR, there has to be an HLR MAP and possibly an EIR MAP, and an AC. In the BSC, there is a BSSAP. In the IN, the SSPs, and the SCPs there are INAPs.

In remote nodes, there always have to be an SCMG and those subsystems to which messages are sent with SPC and SSN addressing. In the MSC, all the BSSAPs in the

CC country code

NDC national destination code

MSIN mobile subscriber identification number

VLRMAP

TC

SCCP

MTP MTP

SCCP

MTP

SCCP

MTP

SCCP

MTP

HLRMAP

TC

SCCP

MTP

GTT2

GTT1

GTT3 GTT4

MSC1 PSTN1 PSTN2 PSTNX MSCY HLRZ

GTT5

GTT1 CC NDC MSIN

GTT2 CC NDC MSIN

GTT3 CC NDC MSIN

GTT4 CC NDC MSIN

GTT5 CC NDC MSIN

DN98785195 33



BSCs have to be defined, and in all the BSCs, the BSSAP of the MSC has to be defined. Otherwise, the definition depends on how addressing is used.

Distribution of status data (broadcast)There are two types of broadcast: 'to network' and 'local' broadcast.

To network:

There is no absolute need for the definition of a broadcast to network because the response method is always active and all the necessary status data are delivered to the network. Normally, this only takes a little time. The broadcast can be set, for example, to inform some SCCP-level STPs about the status of the subsystems to which the STP sends messages with the SPC and SSN address.

Local:

Currently, the only subsystem that needs local broadcast is the BSSAP. In the MSC, the local BSSAP has to know the status data of the BSSAPs located in the BSCs, and in the BSC, the local BSSAP has to know the BSSAP in the MSC.

SCCP backupsOn the SCCP level, backups (replicas) can be those of either signalling points or sub-systems. Signalling point backups are in practice GTT backups. This means that messages are normally sent to one primary STP for GTT, but in the case of a failure, another STP capable of the same GTT can be used.

Currently, the only relevant backups for subsystems can be databases (that is, IN SCPs). Backups can be defined for SPs, subsystems, and also for GTT results.

Only one backup is active, so when a GTT result has a backup, other possible backups are not used.

SCCP load sharingOn the SCCP level, it is possible to define load sharing for up to 16 destinations. Each load sharing destination has destination priority. Priority value 1 presents the highest pri-ority, priority value 2 presents the lower priority. By priority value, the primary-backup concept can be incorporated into the GT load sharing. It means that the traffic is shared between the primary destinations, that is, priority value 1 destinations, as long as there is at least one primary destination available. If there is no primary destination available, the traffic is shared between the backup destinations, that is, destinations with priority value 2. Fallback to the primary destinations is done when at least one primary destina-tion becomes available.

SCCP routing selects the destination based on different methods for protocol class 0 messages and protocol class 1 messages. The selection is made among the available destinations with the highest priority; if there is not a highest priority destination avail-able, the selection is done among the lower priority destinations that are available.

For protocol class 0 messages, SCCP routing selects the destinations according to the order in the result. SCCP routing keeps track of which the next destination to be selected is. If there are, for example, four available priority value 1 destinations (that is, highest priority destination) in the result, they are selected in 1, 2, 3, 4, 1, 2, 3, 4, order and so on.

For protocol class 1 messages, SCCP routing selects the destination according to the SLS value in the incoming message. The incoming SLS is not used directly, but an internal SLS value is calculated based on the incoming SLS and the OPC. The selection

34 DN98785195




of the destination index is done by mapping the internal SLS value to a destination index. Mapping is based on the SLS value range division into as many parts as many destina-tions are in a result. The destination count is the amount of available highest priority des-tinations in the result; if none, the available lower priority destinations are used in load sharing.

If there are two destinations in the GT result, and load sharing is not used, the secondary result is used as a normal backup destination of the primary result.

Load sharing is taken into use when creating or modifying GTT results with the NAC or NAM command.

In addition, on the SCCP level, MTP load sharing can be used when messages are sent to the STPs for GTT. This can be done so that in the STP nodes a common MTP alias point code is defined for them, and in the sending node, a route set using the two STPs with load sharing, is defined for the alias point. SCCP is also defined for that alias point in the sending node and GTT is defined so that it leads to the alias point. In this case, messages are sent to these two STPs through load sharing.

DN98785195 35

Common Channel Signalling (MTP, SCCP and TC) Creating MTP configuration

Id:0900d8058062403dConfidential

4 Creating MTP configurationIn most cases, the MTP needs to be configured in the network element. Before config-uring the MTP, you must plan the signalling network with great care.

Before you startCheck if the network element has all the necessary equipment and software.

If you are sure that all equipment and software needed for signalling already exists on the network element, you can continue with Create SS7 services.

Steps

1 Check if a signalling unit has been created in the network element (WTI)Depending on the type of your network element, the CCSU, BSU or BCSU can act as the signalling unit. Notice that the network element may have several signalling units created for different purposes. For example, the mobile switching centre (usually) has both a CCSU and a BSU.

Use the following command to display all the existing CCSUs of the network element:

ZWTI:U:CCSU;

Create the signalling unit if necessary, see the instructions for Creating computer unit description in Hardware Configuration Management.

2 Check if the signalling unit has signalling link terminals (AS7) and if there are free signalling links (WTI, NCI)Since a signalling link terminal can hold 128 (AS7-D), 64 (AS7–C), 16 (AS7–V and AS7–A), four (AS7-U), or one (AS7-S) signalling links, you have to check the existing signal-ling link terminals and the existing signalling links to find out if there is a need to add any signalling link terminals.

Use the following command to display the CCSUs and their signalling link terminals.

ZWTI:P:CCSU;

Use the following command to display the existing signalling links.

ZNCI;

If the network element does not have enough free signalling link terminals, you have to create some.

3 Add signalling link terminals if neededAdd a signalling link terminal when you want to increase the signalling capacity, but the existing signalling link terminals cannot hold any more signalling links.

g When adding signalling link terminals to a signalling unit, remember to check if the back-up units have an equally large link capacity, so that the signalling capacity of the network element will not decrease when the unit is changed. The link capacities of the different types of signalling units (CCSU, BSU) do not need to be equal, since they cannot back up each other.

36 DN98785195



Creating MTP configuration

a) Check the jumper settings on the signalling link terminal, and place the plug-in unit in its slot

fWhen you handle the plug-in units, remember to protect them from static electricity and wear a resistive wrist wrap or a similar purpose grounding device. The compo-nents of the plug-in units or other units may be damaged by electrostatic discharge. Avoid touching the contacts and connector surfaces.

More information on jumper settings can be found in the instructions for jumper set-tings.

g The slot number 6 is the first one in which the AS7 unit can be installed. You can check if the jumper settings have been set successfully by giving the WTI command.

b) Create the plug-in unit of the signalling link terminal in the signalling unit (WTP)Example: Creating a plug-in unitUse the following command example to create a 4-channel signalling link terminal in CCSU 0, whose internal PCM is 30 and its time slots are 0-3. (You can check the number of the PCM from the corresponding Site documents.)ZWTP:CCSU,0:AS7_U,1,6::CCS7,4,30,TSL,0&&3:;

c) Connect the signalling link terminal to the signalling unit (WUC)Example: Connecting the plug-in unitUse the following command to connect the AS7-U (number 1) plug-in unit to the CCSU-0 signalling unit:ZWUC:CCSU,0:AS7_U,1:;After all terminals have been equipped, you can create signalling channels for them.

4 Create SS7 servicesThe signalling messages coming into the network element can be transmitted to the network element's own user parts, or they can be switched forwards, or both. Depending on the services configured in the network element, some of the signalling messages are unnecessary. Data on service information determines how the signalling messages coming into the network element are received and switched.

a) Check if all necessary services exist (NPI)Check if all needed services exist in the network element by using the NPI command. The services SNM and SNT usually exist automatically in the network element.

Name of the service (recommendation)

Service Value for the service indicator index parame-ter

SNM SIGNALLING NETWORK MANAGEMENT MESSAGES 00H

SNT SIGNALLING NETWORK TESTING AND MAINTE-NANCE MESSAGES

01H

Table 1 The services, their recommended names and parameter values given in the NPC command

DN98785195 37



If all necessary services exist, you can continue with the Step Create own MTP sig-nalling point.

b) Create the necessary services (NPC)Use the <service existing for STP messages> and <service existing for user part of own signalling point> parameters to choose whether the service is active for the STP messages and/or for the user parts of the own sig-nalling point.Check the process family identifiers from the Site Specific Documents as there can be some exceptions to the values given in the following example commands.ZNPC:<signalling network>,00,SNM:Y:Y,07F,06D;ZNPC:<signalling network>,01,SNT:Y:Y,07F,;ZNPC:<signalling network>,03,SCCP:Y:Y,208,10F;

5 Create own MTP signalling point (NRP)The own signalling point has to be defined before you can create the other objects of the signalling network. Use the NRP command to create the own MTP signalling point. A network element can be connected to several signalling networks. The NRI command displays all the existing signalling points.

There are special network-specific parameters related to the signalling networks, and you can output them using the NMO command. These parameters define, for example, the congestion method used in the signalling network. For more information on the network-specific parameters, refer to SS7 signalling network parameters.

g The same NRP command is used to create a new signalling network.

ZNRP:<signalling network>,<signalling point code>,<signalling point name>,STP:<ss7 standard>:<number of spc subfields>:<spc subfield lengths>;

SNTA ANSI - SIGNALLING NETWORK TESTING AND MAIN-TENANCE MESSAGES

02H

SCCP SIGNALLING CONNECTION CONTROL PART 03H

TUP TELEPHONE USER PART 04H

ISUP ISDN USER PART 05H

DUP0 DATA USER PART (CALL AND CIRCUIT RELATED MESSAGES)

06H

DUP1 DATA USER PART (FACILITY REGISTRATION AND CANCELLATION MSGS)

07H

BICC BEARER INDEPENDENT CALL CONTROL 0DH

Name of the service (recommendation)

Service Value for the service indicator index parame-ter

Table 1 The services, their recommended names and parameter values given in the NPC command

38 DN98785195




6 Create TDM signalling links and link setThe parameter set related to the signalling link can be used to handle several of the sig-nalling link timers and functions. If the ready-made parameter packages do not cover all the occurring situations, you can create more parameter sets, modify the relevant parameters, and then attach the new parameter set to the signalling link. It is recom-mended to check if there will be such special situations before you start configuring the MTP. For more information, see Section Signalling link parameters. Here are two examples of special situations that require modifications in the parameter set:

• One of the signalling links works via satellite, and the level 2 error correction method has to be preventive_cyclic_retransmission instead of the usual basic_method.

• National SS7 specification defines some of the timer values, so they are different from the ones set by the general recommendations.

a) Create signalling links (NCC)ZNCC:<signalling link number>:<external PCM-TSL>,<link bit rate>:<unit type>,<unit number>:<parameter set number>;Remember to check with the WTI command if the network element is adequately equipped before you start creating signalling links.It is recommended to create the signalling links belonging to the same signalling link set in different signalling units if it is possible. Thus a changeover of the signalling unit does not cause the whole signalling link set to become unreachable.

g The signalling link code (SLC) and the time slot (TSL) have to be defined in such a way that they are the same at both ends of the signalling link.You can number the signalling links within the network element as you wish. The default value for the number is always the next free number.To interrogate existing signalling links, use the NCI or NEL command.

b) Create SS7 signalling link set (NSC) for each destination.A signalling link set consists of one or several links. The signalling links belonging to the signalling link set cannot be activated until the signalling link set is connected to a signalling route set.You can reserve several links for a link set with the NSC command. You can add links to a signalling link set later with the NSA command.ZNSC:<signalling network>,<signalling point code>,<signalling link set name>:<signalling link number>,<signalling link code>;The parameters <signalling network> and <signalling point code> define the network element where the signalling link set leads to.To interrogate the existing signalling link sets, use the NSI or NES command.

7 Create IP signalling configurationFor more information, see Section Creating IP signalling configuration in SS7 Signalling Transport over IP.

8 Create signalling route set (NRC)When a signalling route set is created, a parameter set is attached to it. The parameter set can be used to handle several MTP3 level functions and related matters such as the

DN98785195 39



A interface used between the MSC and the BSC. If the predefined parameter sets do not cover all the occurring situations, you can create more parameter sets, modify the relevant parameters, and then attach the new parameter set to the signalling route set. For more information, see Section Signalling route set parameters.

Create a signalling route set for each destination.

You can create all signalling routes that belong to the same route set at the same time with the same command. Later you can add some more signalling routes to a route set with the NRA command.

ZNRC:<signalling network>,<signalling point code>,<signalling point name>,<parameter set number>,<load sharing status>,<restriction status>:<signalling transfer point code>,<signalling transfer point name>,<signalling route priority>;

The parameters <signalling transfer point code> and <signalling transfer point name> are used when the created signalling route is indirect, that is, the route goes through a signalling transfer point (STP).

g A signalling point cannot be used as an STP unless it is first equipped with a direct sig-nalling route.

To add signalling routes to an existing signalling route set, use the NRA command.

4.1 Activating MTP configurationSteps

1 Allow the activation of the signalling links (NLA)Use the following command to allow the activation of previously created signalling links:

ZNLA:<signalling link numbers>;

2 Activate the signalling links (NLC)Use the following command to activate the previously created signalling links:

ZNLC:<signalling link numbers>,ACT;

The signalling links assume either state AV-EX (active) or UA-INS if the activation have not succeeded. Activation may fail because links at the remote end are inactive or the transmission link is not working properly.

To interrogate the states of signalling links, use the NLI or NEL command.

3 Allow activation of the signalling routes (NVA)Use the following command to allow the activation of previously created signalling routes:

ZNVA:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>;

40 DN98785195




4 Activate signalling routes (NVC)The following command activates the previously created signalling routes:

ZNVC:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>:ACT;

To interrogate the states of signalling routes, use the NVI, NER, or NRI command.

When you are dealing with a direct signalling route, the signalling route set assumes state AV-EX if the related link set is active; otherwise it assumes state UA-INS. A sig-nalling route going through an STP can also assume state UA-INR if the STP has sent a Transfer Prohibited (TFP) message concerning the destination point of the route set. For more information, see Section States of signalling routes.

Example: Activating signalling routesIn this example, you change the state of a signalling route which leads to signalling point 302. The route is defined in signalling point 301, which is located in the national signal-ling network NA0.

a) Change the signalling route state to ACTIVATION ALLOWED.b) Take the signalling route into service.

ZNVA:NA0,302:;The execution printout is as follows:

ALLOWING ACTIVATION OF SIGNALLING ROUTE

DESTINATION: SP ROUTES: SPNET SP CODE H/D NAME NET SP CODE H/D NAME--- ------------------ ----- --- ------------------ -----NA0 0302/00770 MSC2 NA0 0302/00770 MSC2 ACTIVATION ALLOWED

COMMAND EXECUTEDc) Use the NVC command to activate the route.

ZNVC:NA0,302::ACT;The execution printout is as follows:

CHANGING SIGNALLING ROUTE STATE

DESTINATION: SP ROUTES: SP OLD NEWNET SP CODE H/D NAME NET SP CODE H/D NAME STATE STATE PRIO--- ------------------ ----- --- ------------------ ----- ------- ------- ----NA0 0302/00770 MSC2 NA0 0302/00770 MSC2 UA-INU AV-EX 2SIGNALLING ROUTE ACTIVATING FAILED

COMMAND EXECUTED

4.2 Setting MTP level signalling traffic load sharingWith MTP level signalling traffic load sharing, you can share the signalling traffic between signalling routes and between signalling links belonging to the same link set.

Within a signalling link set, load sharing is implemented in such a way that it automati-cally covers all the links that are in active state.

DN98785195 41



Load sharing between signalling routes takes effect only after you have allowed load sharing by defining the same priority for all signalling routes and by allowing load sharing in that route set.

Before you startBefore setting load sharing, plan carefully which kind of load sharing is suitable in the signalling network. For more information, see Section MTP level signalling network.

Steps

1 Check signalling route priorities and load sharing status (NRI)ZNRI:<signalling network>,<signalling point code>;

2 Check MTP load sharing data (NEO)Check which signalling links transmit each of the Signalling Link Selection Field (SLS) values. You can use this command to separately interrogate the load sharing data con-cerning either the messages generated by the own signalling point or STP signalling traffic (for example, for STP traffic according to the ANSI standards, the load sharing system is different).

ZNEO;

3 Modify signalling route priority, if needed (NRE)The priority can vary between 0 and 7, the primary priority being 7.

ZNRE:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>,<new signalling route priority>;

4 Allow load sharing in the signalling route set, if needed (NRB)If you want to activate load sharing and it is not already allowed in the signalling route set in question (see the output of the NRI command), you have to change the load sharing status.

ZNRB:<signalling network>,<signalling point codes>:LOAD=<load sharing status>;

4.3 Creating large capacity signalling link Before you startBefore you can create a large capacity link, you must consider and plan it carefully. For more information, see Section MTP level signalling network.

• The large capacity signalling link feature is supported only with the AS7-V, AS7–VA, AS7-A, AS7–C and AS7–D signalling terminal types.

• All signalling units must have a similar signalling terminal configuration. When the switchover of the signalling unit having large capacity signalling links is performed, there has to be a signalling terminal supporting large capacity signalling link in the spare unit.

42 DN98785195




• Both ends of the signalling link have to support the large capacity signalling link. The time slots of the external PCM for the large capacity signalling link have to be in a consecutive order.

Steps

1 Check the signalling terminals (WTI)Check with the WTI command if there are either AS7–X, AS7–V, or AS7–VA (in DMC bus based DX 200) or AS7–A, AS7–C and AS7–D (in PCI bus based DX 200) signalling terminals in the signalling unit.

If there is no signalling link terminal configured in the network element, configure AS7–X, AS7–V, AS7–VA, AS7–A, AS7–C or AS7–D in all signalling units depending on the CPU type of the unit (AS7–X, AS7–V, or AS7–VA for DMC bus based and AS7–A, AS7–C and AS7–D for PCI bus based DX 200 network elements). If there are, for example, and BSU types of signalling units in the same network element, only the used type of signalling unit needs to have AS7–V, AS7–VA, AS7–A, AS7–C or AS7–D.

2 Check the PCM-TSL capacityCheck the status of the time slots of the external PCM which are intended to give infor-mation to the new large capacity signalling link and if those time slots are free and in a consecutive order.

g Both ends of the signalling link must have the same time slots for the signalling link.

If there are no free time slots or they are not in a consecutive order, select other time slots or change the configuration in such a way that required time slots can be used with the signalling link.

3 Create large capacity signalling link (NCC) Choose the right capacity for the link with the <link bit rate> parameter of the NCC command.

Create all large capacity signalling links in the same signalling unit at the same time to avoid unnecessary unit restarts.

4 Create a new signalling link set (NSC) or add a the signalling link to an existing signalling link set (NSA)

• Create a new signalling link set (NSC)Use the NSC command to create a new signalling link set.

• Add a the signalling link to an existing signalling link set (NSA)Use the NSA command to add the previously created signalling link to an existing signalling link set.

5 Initialise the signalling terminal, if needed (NCI)Check the status of the previously created signalling link.

Check if there is the following information in the output of the NCI command:

SIGNALLING UNIT SWITCHOVER IS REQUIRED BEFORE LINK CAN BE ACTIVATED

DN98785195 43



a) Make a controlled switchover to the spare unit (USC)If the signalling unit has a spare unit, make a controlled switchover to the unit, that is, change the state of the current signalling unit from WO-EX to SP-EX with the USC command.ZUSC:BCSU,1:SP;

b) Restart the unit (USU)If the signalling unit does not have a spare unit, restart the unit with the USU command. Note that during the restart, the signalling links connected to the signal-ling unit are cut.ZUSU:BCSU,1;

6 Create a new signalling route set, if needed (NRC)If the created signalling link leads to a signalling point where a signalling route set already exists, there is no need to create a new signalling route set. If there is no signal-ling route set in the signalling point, create it with the NRC command.

7 Allow activation of the large capacity signalling link (NLA)ZNLA:14;

8 Activate the large capacity signalling link (NLC)ZNLC:14,ACT;

44 DN98785195


Id:0900d805803b5b33Confidential

Creating SCCP configuration

5 Creating SCCP configurationThe SCCP is needed in a network element if the element:

• is used for switching GSM calls • is used for switching IN services • acts as SCCP-level Signalling Transfer Point (STP)

Before you startCheck if the whole network has been carefully planned, all necessary hardware has been installed in the network element, and the Message Transfer Part (MTP) has already been configured.

Perform the following tasks:

• Check if the signalling points have been created on the MTP (NRI command) and the services are available for the SCCP (NPI command).

• Check which parameter set is used, and whether there is a need to modify the values of the existing parameter sets to meet the present conditions and require-ments (OCI command).

• Check which subsystems are used. • Check the data in the subsystem parameter sets (OCJ command) and the possible

modifications in them (OCN command). • Check if the SCCP service has been created on the MTP level.

Before you can create the SCCP in the network element, the SCCP service has to be created. To check if the service has been created, use the NPI command. If there is no SCCP service created on the MTP level, create it with the NPC command (for more information, see Section Creating MTP configuration).

g The SCCP management subsystem (SCMG) is automatically created when you create an SCCP for a signalling point.

g The subsystems which use the Transaction Capabilities (TC) are configured in a similar way, and no further configuration is needed (as the TC is automatically used for suitable subsystems).

Steps

1 Create own SCCP signalling point and subsystems (NFD)Before you start creating the signalling point or its subsystems, check what is the Sig-nalling Point Code (SPC) of the system's own signalling point with the NRI command.

ZNFD:<signalling network>,<signalling point code>,<signalling point parameter set>:<subsystem number>,<subsystem name>,<subsystem parameter set number>,<subsystem status test>;

g The value YES for the <subsystem status test> parameter is valid only when the WHITE_BOOK_MGMT_USED (12) parameter of the used SCCP signalling point parameter set has the value YES (check this with the OCI command).

When an SCCP signalling point and SCCP subsystems are created, a parameter set is attached to them. In most cases predefined parameter sets are the most suitable, but if the predefined parameter sets do not cover all the occurring situations, you can create

DN98785195 45

Common Channel Signalling (MTP, SCCP and TC) Creating SCCP configuration


more parameter sets, modify the relevant parameters, and attach the new parameter set to the SCCP signalling point and SCCP subsystem.

2 Create remote SCCP signalling points and subsystems (NFD)In addition to creating the own SCCP signalling point and its subsystems, you also need to define the other SCCP signalling points and the subsystems of the other SCCP sig-nalling points of the network, which are involved in SCCP level traffic.

ZNFD:<signalling network>, <signalling point code>, <signalling point parameter set>: <subsystem number>, <subsystem name>, <subsystem parameter set number>,Y;

You can add more subsystems to a signalling point with the NFB command. The system may need new subsystems, for example, when new services are installed, software is upgraded, or the network is expanded.

When you are adding subsystems, you need to know which parameter set you want the subsystems to use or which one has to be used.

You can display the existing parameter sets with the OCJ command. When you want to modify the parameters, use the OCN command, and to create a new parameter set, use the OCA command.

3 Create translation results (NAC)The translation result refers to those routes where messages can be transmitted. All the signalling points that are meant to handle SCCP level traffic must be defined at a signal-ling point.

At this stage you have to decide whether the routing is based on the Global Title (GT) or on the subsystem number.

ZNAC:NET=<primary network>,DPC=<primary destination point code>,RI=<primary routing indicator>;

If you want to have a back-up system for routes or the network, you can create alterna-tive routes that will be taken into service if the primary route fails. Also, it is possible to use load sharing for up to 16 destinations by giving the value YES for the <load sharing> parameter.

4 Create global title analysis, if necessary (NBC)Before creating the global title analysis, check the number of the translation result so that you can attach the analysis to a certain result. Use the NAI command.

ZNBC:ITU=<itu-t global title indicator>,LAST=<last global title to be analysed>:TT=<translation type>,NP=<numbering plan>,NAI=<nature of address indicator>:<digits>:<result record index>;

5 Set broadcast status if needed (OBC, OBM)There are two different types of broadcasts you can set:

• local broadcast status (OBC command): it is used to inform the subsystems of the own signalling point about changes in the subsystems of the remote signalling points

46 DN98785195



Creating SCCP configuration

• broadcast status (OBM command): it is used to inform other signalling points about changes in the subsystems of the own signalling point or the subsystems of the sig-nalling points connected to the own signalling point

When you set local broadcasts, remember that also the remote network elements have to be configured in such a way that they send the status data to your network element.

g When setting the broadcasts, consider carefully what broadcasts are needed. Incorrect or unneccessary broadcasts can cause problems and unnecessary traffic in the signal-ling network.

Local broadcasts:

ZOBC:<network of affected subsystem>,<signalling point code of affected subsystem>,<affected subsystem number>:<network of local subsystem>,<local subsystem number>:<status>;

Remote broadcasts:

ZOBM:<network of affected subsystem>,<signalling point code of affected subsystem>,<affected subsystem number>:<network of concerned signalling point>,<concerned signalling point code>:<status>;

Further informationFor more information, see Section SCCP level signalling network.

5.1 Activating SCCP configurationFollow the steps below to activate the SCCP configuration.

Steps

1 Activate remote SCCP signalling points (NGC)ZNGC:<signalling network>,<signalling point codes>:ACT;

You do not have to activate the own SCCP signalling point; only the remote SCCP sig-nalling points.

To check if the signalling point is really active, use the NFI command. In the command printout, the state of signalling point should be AV-EX. If the signalling point assumes state UA-INS, there is a fault on the MTP level. You can also display the states of SCCP signalling points with the NGI command.

g If you use the default values in the command, only the signalling points of network NA0 are shown.

Example: Displaying the states of SCCP signalling pointsWhen you examine an example system using the NFI or NGI command, all signalling points should be in normal AV-EX state. Note that signalling point 101H is not visible because the SCCP is not defined in it.

For the ZNGI:NA0,:N; command, the execution printout can be as follows:

DX 200 DX200-LAB 2004-10-02 14:37:27

SCCP STATES

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Common Channel Signalling (MTP, SCCP and TC) Creating SCCP configuration


DESTINATION: SP ROUTING: SPNET SP CODE H/D NAME STATE RM NET SP CODE H/D NAME STATE--- ------------------ ----- ----- -- --- ------------------ ----- -------NA0 0102/00258 PSTN2 AV - NA0 0102/00258 PSTN2 AV-EXNA0 0300/00768 HLR AV - NA0 0300/00768 HLR AV-EXNA0 0301/00769 MSC1 OWN SPNA0 0302/00770 MSC2 AV - NA0 0302/00770 MSC2 AV-EX

NA0 0311/00785 BSC1 AV - NA0 0311/00785 BSC1 AV-EX

NA0 0312/00786 BSC2 AV - NA0 0312/00786 BSC2 AV-EX

COMMAND EXECUTED

2 Activate local and remote SCCP subsystems (NHC)ZNHC:<signalling network>,<signalling point codes>:<subsystem>:ACT;

To display the subsystem states, use the NHI or NFJ command.

When remote subsystems are being activated, their status is not checked from the remote node. The remote subsystem status becomes AV-EX if the remote node is avail-able, although the actual subsystem may be unavailable or even missing. The status of the unavailable subsystem is corrected with the response method as soon as a message is sent to it.

Use the NHI command to check if the subsystems have assumed state AV-EX. If not, the reason may be faulty or missing distribution data. Correct the distribution data and check the state again. Another reason for the subsystems not to be operating is that the subsystem at the remote end is out of service.

3 Set the SS7 network statistics if neededBy setting SS7 network statistics, you can monitor the performance of the SS7 network. You do not have to do it in the integration phase; you can do it later.

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Id:0900d805806d3938Confidential

Optimising MTP configuration

6 Optimising MTP configurationAfter the initial setup, you can optimise your MTP configuration by:

• modifying the MTP level 3 signalling parameters • modifying the SS7 signalling network parameters • modifying the signalling link parameter set • modifying the signalling link route parameter set • setting/modifying the MTP level signalling traffic restrictions • modifying the MTP level signalling traffic load sharing • using the signalling link set of another signalling network • removing the MTP signalling point

6.1 Modifying MTP level 3 signalling parametersMTP level 3 signalling parameters define the functions of the whole MTP of the network element. Some of the parameter values are related to monitoring the functions, while others define various limits and timers.

Modify the values of these parameters when you think that some of the MTP level 3 timers values are not suitable.

Before you startAs MTP level 3 parameters affect the whole network element's SS7 signalling, make sure that the change will not cause any malfunctions in the signalling system.

In most cases, the predefined parameters are the most suitable ones.

Steps

1 Check MTP level 3 parameters (NMI)You can display the used parameter values grouped by parameter sets with the NMI command.

2 Modify MTP level 3 parameter (NMM)ZNMM:<parameter group>:<parameter name>=<parameter value>;

6.2 Modifying SS7 signalling network parametersSS7 signalling network parameters apply to the whole signalling network. This means that SS7 signalling network parameters can be separately defined for each signalling network (NA0, NA1, IN0, and IN1).

Before you startAs SS7 signalling network parameters affect the whole signalling network, make sure that the change will not cause any malfunctions in the signalling system.

In most cases predefined parameters are the most suitable ones.

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Common Channel Signalling (MTP, SCCP and TC) Optimising MTP configuration


Steps

1 Check parameter values (NMO)You can display the used parameters in each signalling network with the NMO command.

2 Modify SS7 signalling network parameters (NMC)ZNMC:<signalling network>:<parameter group>:<parameter name>=<parameter value>;

6.3 Modifying the values of signalling link parameter setThe parameters in the signalling link parameter set define the function of the signalling link. You can create several signalling link parameter sets for different types of signalling links. Each signalling link uses the signalling link parameter set attached to it.

Before you startAs the signalling link parameters affect all the signalling links which use that certain sig-nalling link parameter set, make sure that the change will not cause any malfunctions in the signalling system.


g If you change the values of an existing signalling link parameter set, you have to deac-tivate all the signalling links using that particular parameter set. This means that all sig-nalling traffic in these signalling links stops and all calls using these signalling links will be cut.

The best way to modify signalling link parameters is to create a new parameter set and attach it, one by one, to each signalling link. This procedure is useful when a new network element is taken into use but is not used for the actual call transmission.

Steps

1 Check signalling links and the parameter sets they use (NCI)As the modifying of the values of an existing parameter set affects all signalling links using that signalling link parameter set, check whether this can be done. If you want only a certain group of signalling links to have different signalling link parameter values, you should create a new signalling link parameter set and attach it to those signalling links.

You can output all signalling links and the signalling link parameter sets they use with the NCI command.

2 Deactivate signalling links using the parameter set you want to modify (NLC)The new values of the parameter set become active when the signalling links that use the parameter set are first deactivated and then they are activated again.

ZNLC:<signalling link numbers>,INA;

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3 Modify values of signalling link parameter set (NOM)ZNOM:<signalling link parameter set number>,<signalling link parameter set name>,<parameter group>:<parameter number>,<parameter value>;

4 Activate signalling links using the modified parameter set (NLC)ZNLC:<signalling link numbers>,ACT;

6.4 Creating new signalling link parameter setThe parameters in the signalling link parameter set define the function of the signalling link. You can create several signalling link parameter sets for different types of signalling links. Each signalling link uses a signalling link parameter set attached to it.

Before you startAs the signalling link parameters affect all signalling links which use that certain signal-ling link parameter set, make sure that the change will not cause any malfunctions to the signalling system.


g If you change the values of an existing signalling link parameter set, you have to deac-tivate all signalling links using the parameter set. This means that all signalling traffic in these signalling links stops and all calls using these signalling links will be cut.

The best way to modify signalling link parameters is to create a new parameter set and attach it, one by one, to each signalling link. This procedure is useful when a new network element is taken into use but is not used for actual call transmission.

Steps

1 Check signalling links and the parameter sets they use (NCI)You can output all signalling links and the signalling link parameter sets they are using with the following command.

ZNCI;

2 Copy existing signalling link parameter set with a new name (NOE)The best way to create a new signalling link parameter set is to copy an old parameter set with a new name. Choose the best suitable parameter set to be the source param-eter set.

ZNOE:<source signalling link parameter set number>,<source signalling link parameter set name>:<signalling link parameter set number>,<signalling link parameter set name>;

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3 Modify values of the new signalling link parameter set (NOM)ZNOM:<signalling link parameter set number>,<signalling link parameter set name>,<parameter group>:<parameter number>,<parameter value>;

4 Deactivate the signalling links that you want to use with the new parameter set (NLC)It is reasonable to deactivate only a few of the signalling links at a time if you want sig-nalling traffic to be transmitted normally during the modification.

ZNLC:<signalling link numbers>,INA;

5 Change parameter set of signalling link (NCL)Replace the existing parameter set of the signalling link with the new signalling link parameter set.

ZNCL:<signalling link number>:<parameter set number>;

6 Activate signalling links using the new parameter set (NLC)ZNLC:<signalling link numbers>,ACT;

6.5 Modifying the values of signalling route set parameter setThe parameters in the signalling route set parameter set define the signalling route set signalling functions. You can create several signalling route set parameter sets for dif-ferent types of signalling route sets. Each signalling route set uses a parameter set for the signalling route set attached to it.

Before you startAs the signalling route set parameters affect all signalling route sets which use the same signalling route set parameter set, make sure that the change will not cause any mal-functions to the signalling system.

In most cases the predefined parameters are the most suitable ones.

Steps

1 Check signalling route sets and the parameter sets they use (NRI)As the modification of the values of an existing parameter set affects all the signalling route sets using that signalling route set parameter set, consider if this can be done. If you want only certain signalling route sets to have different values in the signalling route set parameters, you should create a new signalling route set parameter set and attach it to those signalling route sets.

You can output all signalling route sets and the signalling route set parameter sets they are using with the following command.

ZNRI;

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If you only want to modify the values of a certain signalling route set parameter set, continue to the next step, but if you want to create a new signalling route set parameter set, continue with the pocedure of .

2 Modify values of signalling route set parameter set (NNM)ZNNM:<signalling route set parameter set number>,<signalling route set parameter set name>,<parameter group>:<parameter number>=<parameter value>;

3 Deactivate signalling route sets using the modified parameter set (NVC)The new values of the parameter set do not become active until the signalling route set that uses the parameter set is first deactivated and activated again.

ZNVC:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>:INA;

4 Activate signalling route sets using the modified parameter set (NVC)ZNVC:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>:ACT;

6.6 Creating new signalling route set parameter setThe parameters in the signalling route set parameter set define the signalling route set signalling functions. You can create several signalling route set parameter sets for dif-ferent types of signalling route sets. Each signalling route set uses a signalling route set parameter set attached to it.

Before you startAs the signalling route set parameters affect all the signalling route sets which use the same signalling route set parameter set, make sure that the change will not cause any malfunctions to the signalling system.

In most cases the predefined parameters are the most suitable ones.

Steps

1 Check signalling route sets and the parameter sets they use (NRI)As the modification of the values of an existing parameter set affects all the signalling route sets using that signalling route set parameter set, consider if this can be done. If you want only certain signalling route sets to have different values in the signalling route set parameters, you should create a new signalling route set parameter set and attach it to those signalling route sets.

You can output all the signalling route sets and the signalling route set parameter sets they are using with the following command:

ZNRI;

If you just want to modify the values of a certain signalling route set parameter set, continue with the procedure of , but if you want to create a new signalling route set parameter set, continue with the next step.

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2 Copy existing signalling route set parameter set with a new name (NNE)The best way to create a new signalling route set parameter set is to copy an old param-eter set with a new name. Choose the best suitable parameter set to be the source parameter set.

ZNNE:<source signalling route set parameter set number>,<source signalling route set parameter set name>:<signalling route set parameter set number>,<signalling route set parameter set name>;

3 Modify values of the new signalling route set parameter set (NNM)ZNNM:<signalling route set parameter set number>,<signalling route set parameter set name>,<parameter group>:<parameter number>=<parameter value>;

4 Change parameter set of signalling route set (NRB)Replace the existing parameter set of the signalling route set with the new signalling route set parameter set.

ZNRB:<signalling network>,<signalling point codes>:PARA=<parameter set number>;

Further information

Example: Creating new signalling route set parameter setWith the following example, you can create a new signalling route set parameter set with the name MIKA (number 7) by copying the existing parameter set number 0 (ITU-T). First, change the value of the parameter D2 (TFC_DENIED) to YES, then change the signalling route sets in signalling network NA0 leading to signalling point 300 to use this parameter set.

1. Check the signalling route sets and the parameter sets they use.ZNRI;

2. Copy one of the existing signalling route set parameter sets with a new name.ZNNE:0,:7,MIKA;

3. Modify the values of the new signalling route set parameter set.ZNNM:7,D:D2=YES;

4. Change the parameter set of the signalling route set.ZNRB:NA0,300:PARA=7;

6.7 Setting and modifying MTP level signalling traffic restric-tionsYou do not have to define the policing at the same time when configuring the signalling network. You can do it later when you see how the network is working.

Plan the traffic restrictions that you need carefully.

Before setting any traffic restrictions, it is necessary to plan carefully what kind of signal-ling traffic you want to allow and deny. Remember the following issues:

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• When signalling traffic is denied on the MTP level, the SCCP level signalling is also denied.

• If STP messages coming from a certain node are denied (not transferred), it is possible that the node in question is not able to send any messages to any direction (for example, when links to some other direction are down).

• It is also possible to set the reports from STP traffic to check if traffic restrictions are necessary.

• You cannot remove a signalling route set which is included in the traffic restrictions. • To a direction where the Abis interface is used (that is, between BSC and BTS

network elements), there is no need to define any traffic restrictions (you can check this with the NRI command).

When you want to change the existing traffic restrictions, it may be necessary to remove some traffic restrictions. Before you can remove an MTP signalling point, you have to clear all the traffic restrictions that are set to that MTP signalling point.

Steps

1 Check existing signalling traffic restriction data (NRT)When you are going to modify signalling traffic restrictions, it is reasonable to first check the existing restrictions to ensure that you are removing the appropriate restrictions, and consider what effects the removal of those restrictions have on your network.

ZNRT:<signalling network>;

2 Modify signalling traffic restriction data (NRS)ZNRS:<policing method>:<signalling network>,<originating/adjacent point codes>,<destination point codes>:<STP message treatment>;

3 Check signalling traffic restriction data (NRT)ZNRT;

6.8 Modifying MTP level signalling traffic load sharingWith MTP level signalling traffic load sharing, you can share the signalling traffic between signalling routes and between signalling links belonging to the same link set.

Within a signalling link set, load sharing is implemented in such a way that it automati-cally covers all the links that are in active state. The priority of a signalling link does not affect the load sharing system.

Load sharing between signalling routes takes effect only after you have allowed load sharing by defining the same priority for all signalling routes and by allowing load sharing in that route set.

Before you startBefore setting the load sharing, plan carefully which kind of load sharing is suitable in the signalling network.

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Steps

1 Check signalling route priorities and load sharing status (NRI)ZNRI:<signalling network>,<signalling point code>;

2 Check MTP load sharing data (NEO)Check which signalling links transmit each of the Signalling Link Selection (SLS) field values. You can use this command to separately interrogate the load sharing data con-cerning either the messages generated by the own signalling point or STP signalling traffic (for example, for STP traffic according to the ANSI standards, the load sharing system is different).

ZNEO:[<signalling network>|<NAO>def],[<destination codes>|<ALL>],[<originator point code>|<originator is own point>def]:[(LINK=[<SLS range>|<S>def])|(SLS=[SLS output>|<ALL>def])def];

3 Modify signalling route priority if needed (NRE)The priority can vary between 0 and 7, the primary priority being 7.

ZNRE:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>,<new signalling route priority>;

4 Allow load sharing in the signalling route set if needed (NRB)If you want to activate the load sharing and in the signalling route set in question it is not already allowed (see the output of the NRI command), you have to change the load sharing status.

ZNRB:<signalling network>,<signalling point codes>:LOAD=<load sharing status>;

6.9 Using the signalling link set of another signalling networkIf there is a need to use more than one network indicators (for example, NA0, NA1, and IN0), it is possible to utilise the signalling link set of any other network.

This means that any signalling network can use the signalling link sets of any other sig-nalling network. In other words, there is a link set between two network elements but there are two or more route sets using the same link set (for more information, see Example Using link set of another signalling network).

g This feature is possible only between two DX 200 network elements.

This kind of arrangement is reasonable to use, for example, for backup connections or when traffic between two network elements in a certain signalling network is low.

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Steps

1 Create own signalling point to the signalling network which uses the signalling link set of another signalling network (NRP)ZNRP:<signalling network>,<signalling point code>,<signalling point name>,<own signalling point handling>:<ss7 standard>:<number of spc subfields>:<spc subfield lengths>;

2 Create signalling route set to the signalling network which uses the signalling link set defined for another signalling network (NRC)ZNRC:<signalling network>,<signalling point code>,<signalling point name>,<parameter set number>,<load sharing status>,<restriction status>:<signalling transfer point network>,<signalling transfer point code>,<signalling transfer point name>,<signalling route priority>;

3 Create route set to the destination point like normal STP route (NRC)ZNRC:<signalling network>,<signalling point code>,<signalling point name>,<parameter set number>,<load sharing status>,<restriction status>:<signalling transfer point network>,<signalling transfer point code>,<signalling transfer point name>,<signalling route priority>;

Further information

Example: Using link set of another signalling networkThe following example shows how and when it is useful to use a link set of another network.

Figure 20 Example network where one network element belongs to two signalling networks (NA0 and NA1)

The example network consists of the following network elements:

• signalling point A, the SPC of which in NA0 is 123 and in NA1 is 1123 • signalling point B, the SPC of which in NA0 is 234 and in NA1 is 1234 • signalling point C, the SPC of which in NA1 is 1456.

In the example, network element C operates only in network NA1. Network elements A and B are mainly working in network NA0, though they have some traffic in network NA1.

SP signalling point

NA0:SP=234

NA1:SP=1234

NA0:SP=123

SP A

NA1:SP=1456

SP B SP C

NA1:SP=1123

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Signalling traffic from A to C is so low that it is not economical to configure a link and link set also to network NA1 between A and B. In this case, it is possible to utilise the link set defined for NA0 between A and B for NA1 network traffic as follows:

1. Create an own point to the NA1 signalling network in SP A:ZNRP:NA1,1123,S1123,STP:ITU-T:1:;

2. Create a route set in the NA1 network to SP B. This uses the link set defined for NA0:ZNRC:NA1,1234,S1234,0,D,N:NA0,234,SP234,7;

3. Create a route set to SP C as a normal STP route:ZNRC:NA1,1456,S1456,0,D,N:NA1,1234,S1234,7;

6.10 Removing MTP signalling pointThis procedure describes how to remove an MTP signalling point.You can follow these steps also when you only want to remove certain signalling links, signalling routes, or signalling route sets.

Before you startBefore removing MTP level signalling configuration, the upper level user parts (for example, SCCP) have to be removed.

Steps

1 Deactivate the signalling route (NVC)ZNVC:NA0,312::INA;

2 Deny the activation of the signalling route (NVD)ZNVD:NA0,312;

3 Deactivate the signalling links (NLC)ZNLC:12&13,INA;

4 Deny the activation of signalling links (NLD)ZNLD:12&13;

5 Make sure that there is no policing (NRT)Check with the NRT command that there is no policing defined to the signalling point which you are about to remove.

6 Remove the policing if needed (NRS)You can remove the policing with the NRS command.

ZNRS:A:312,:A;

ZNRS:O:312,:A;

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7 Delete signalling route set (NRD)ZNRD:NA0,312,BSC2;

8 Delete TDM signalling links

a) Delete signalling links from the link set (NSR)Delete the signalling links from the link set with the NSR command. The last link cannot be deleted this way.

b) Delete the last link by deleting the link set (NSD)Delete the last link from the link set by deleting the link set with the NSD command.

c) Delete signalling links (NCD)ZNCD:12;

9 Delete IP signalling links (optional )

a) Delete the signalling link set (NSD)Delete the signalling link set with the NSD command.

b) Remove the unused association set (OYD)ZOYD:<association set name>;

6.11 Moving a BSC under another MSCIf you need to move your BSC network element under another MSC, you do not have to remove the existing signalling configuration from the BSC: there is a special command for this operation. With this command, it is possible to change the Destination Point Code (DPC) of the MTP and SCCP while the whole routing and speech circuits exist.

g You can use this command only in the BSC. For the changes to take effect, the network element has to be restarted.

Steps

1 Prepare the state of the MTP (NVC, NVD, NLC, NLD)

• Deactivate the signalling route set:ZNVC:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>:<state change>;

• Deny the activation of the signalling route set:ZNVD:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>;

• Deactivate signalling links:ZNLC:<signalling link numbers>,INA;

• Deny the activation of signalling links:ZNLD:<signalling link numbers>;

2 Deactivate the signalling traffic of the SCCP (NGC)ZNGC:<signalling network>,<signalling point codes>:<state change>;

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3 Output the results of the MTP and SCCP statistics concerning the old SPC, if needed (OSD)To stop and result all statistical reports, use the following command:

ZOSD:REP:;

4 Execute the exchanging of the adjacent signalling point code command (NRX)Change the destination point code (DPC):

ZNRX:<old signalling network>,<old signalling point code>:<new signalling network>,<new signalling point code>:<new signalling point name>;

5 Activate MTP (NLA, NLC, NVA, NVC)

• Allow the activation of the signalling links:ZNLA:<signalling link numbers>;

• Activate the signalling links:ZNLC:<signalling link numbers>:ACT;

• Allow the activation of a signalling route set:ZNVA:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>;

• Activate the signalling route set:ZNVC:<signalling network>,<signalling point code>:<signalling transfer point network>,<signalling transfer point code>:ACT;

6 Activate the SCCP (NGC)ZNGC:<signalling network>,<signalling point codes>:ACT;

7 Restart the BSC (USS)ZUSS:SYM:C=DSK;

8 Verify the new network configuration (NRI, NSI, NGI, RCI)

• Interrogate the data of the route set:ZNRI:<signalling network>;

• Interrogate the data of the link set:ZNSI:<signalling network>;

• Interrogate the data of the SCCP:ZNGI:;

• Interrogate the data of circuits:ZRCI:;

Further information

Example: Moving a BSC under another MSCThe following procedure (with the command examples) presents how to use this feature. In the example, the network element BSC2 under MSC1 is moved under MSC2.

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The example network is the same as the one previously used in the MTP configuration. The example commands are given in BSC2.

Figure 21 Example network, where BSC2 is moved under MSC2

Moving a BSC under another MSC

1. Prepare the state of the MTP.To deactivate the signalling route set, use the NVC command.ZNVC:NA0,301:,:INA;To deny the activation of the signalling route set, use the NVD command.ZNVD:NA0,301:,:;To inactivate signalling links, use the NLC command.ZNLC:0&1,INA;To deny the activation of signalling links, use the NLD command.ZNLD:0&1;

2. Prepare the state of the SCCP.To deactivate the signalling traffic of the SCCP (into MSC1), use the NGC command.ZNGC:NA0,301:INA:;

3. Output the results of the MTP and SCCP statistics concerning the old SPC (if nec-essary).To stop and result all statistical reports, use the OSD command.ZOSD:REP:;

4. Execute the exchange of the adjacent signalling point code command.To change the DPC, use the NRX command.ZNRX:NA0,301:NA0,302,MSC2;

MSC2NA0SP=302H

BSC2NA0SP=312H

BSC1NA0SP=311H

MSC1NA0SP=301HVLR

MSC2NA0SP=302H

BSC2NA0SP=312H

BSC1NA0SP=311H

MSC1NA0SP=301HVLR

SP signalling point

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5. Activate the MTP.To allow the activation of the signalling links, use the NLA command.ZNLA:0&1;To activate the signalling links, use the NLC command.ZNLC:0&1,ACT;To allow the activation of a signalling route set, use the NVA command.ZNVA:NA0,302:,:;To activate the signalling route set, use the NVC command.ZNVC:NA0,302:,:ACT;

6. Activate the SCCP.To activate the SCCP, use the NGC command.ZNGC:NA0,302:ACT:;

7. Restart the BSC.ZUSS:SYM:C=DSK;

8. Verify new network configuration.To inquire the data of the route set, use the NRI command.ZNRI:NA0,302;To inquire the data of the link set, use the NSI command.ZNSI:NA0,302;To inquire the data of the SCCP, use the NGI command.ZNGI:NA0,302;To inquire the data of circuits, use the RCI command.ZRCI:GSW::NET=NA0,SP=302;

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Optimising SCCP configuration

7 Optimising SCCP configurationFollow the steps below to optimise the SCCP configuration by using SCCP parameters.

7.1 Modifying SCCP signalling point parameter setThis procedure describes how to create a new SCCP signalling point parameter set or how to modify the SCCP signalling point parameters in an existing SCCP signalling point parameter set.

The parameters in the SCCP signalling point parameter set define the SCCP signalling functions of the own SCCP signalling point and the SCCP signalling functions towards remote SCCP signalling points. You can create several SCCP signalling point parame-ter sets for different types of signalling needs.

Before you startBefore changing the values of an existing SCCP signalling point parameter set, make sure that the change will not cause any malfunctions in the signalling system.


Steps

1 Check SCCP signalling points and the parameter sets they use (NFI)As the modification of the values of an existing SCCP signalling point parameter set affects all the SCCP signalling points using that parameter set, consider whether this can be done. If you want only a certain group of SCCP signalling points to have different values for the SCCP signalling point parameters, create a new SCCP signalling point parameter set and attach it to those SCCP signalling points.

You can output all known SCCP signalling points and the SCCP signalling point param-eter sets they are using with the following command.

ZNFI:;

If you want to create a new SCCP signalling point parameter set, see Section Creating new SCCP signalling point parameter set.

2 Modify values of SCCP signalling point parameter set (OCM)ZOCM:<signalling point parameter set number>,<signalling point parameter set name>:<parameter number>,<parameter value>;

7.2 Creating new SCCP signalling point parameter setThis procedure describes how to create a new SCCP signalling point parameter set or how to modify the SCCP signalling point parameters in an existing SCCP signalling point parameter set.

The parameters in the SCCP signalling point parameter set define the SCCP signalling functions of the own SCCP signalling point and the SCCP signalling functions towards remote SCCP signalling points. You can create several SCCP signalling point parame-ter sets for different types of signalling needs.

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Common Channel Signalling (MTP, SCCP and TC) Optimising SCCP configuration


Before you startBefore changing the values of an existing SCCP signalling point parameter set, make sure that the change will not cause any malfunctions in the signalling system.


Steps

1 Check SCCP signalling points and the parameter sets they use (NFI)As the modification of the values of an existing SCCP signalling point parameter set affects all the SCCP signalling points using that parameter set, consider whether this can be done. If you want only a certain group of SCCP signalling points to have different values for the SCCP signalling point parameters, you should create a new SCCP sig-nalling point parameter set and attach it to those SCCP signalling points.

You can output all known SCCP signalling points and the SCCP signalling point param-eter sets they are using with the following command:

ZNFI;

If you only want to modify the values of a certain SCCP signalling point parameter set, see the procedure of Modifying SCCP signalling point parameter set.

2 Copy existing SCCP signalling point parameter set with a new name (OCE)The best way to create a new SCCP signalling point parameter set is to copy an old parameter set with a new name. Choose the best suitable parameter set to be the source parameter set.

ZOCE:<source signalling point parameter set number>,<source signalling point parameter set name>:<signalling point parameter set number>,<signalling point parameter set name>;

3 Modify values of the new SCCP signalling point parameter set (OCM)ZOCM:<signalling point parameter set number>,<signalling point parameter set name>:<parameter number>,<parameter value>;

4 Inactivate the SCCP signalling point in which you want to use the new parameter set (NGC)ZNGC:<signalling network>,<signalling point codes>:INA;

5 Change parameter set of SCCP signalling point (NFL)Replace the existing parameter set of the SCCP signalling point link with the new SCCP signalling point parameter set.

ZNFL:<signalling network>,<signalling point codes>:<signalling point parameter set number>;

6 Activate the SCCP signalling point in which you want to use the new parameter set (NGC)ZNGC:<signalling network>,<signalling point codes>:ACT;

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Further information

Example: Creating new SCCP signalling point parameter setWith the following example, you can create a new SCCP signalling point parameter set with the name MIKA (number 4) by copying the existing parameter set number 2 (WHITE). First, change the value of parameter 3 (timer Q714_T_IAR) to 300 s. Then, change the own SCCP signalling point to use this parameter set towards signalling point 300 in signalling network NA0.

1. Check SCCP signalling points and the parameter sets they use.ZNFI;

2. Copy an existing SCCP signalling point parameter set with a new name.ZOCE:2,:4,MIKA;

3. Modify the values of the new SCCP signalling point parameter set.ZOCM:4,:3,300;

4. Inactivate the SCCP signalling point you want to use the new parameter set in.ZNGC:NA0,300:INA;

5. Change the parameter set of the SCCP signalling point.ZNFL:NA0,300:4;

6. Activate the SCCP signalling point you want to use the new parameter set in.ZNGC:NA0,300:ACT;

7.3 Defining SCCP signalling point and/or subsystem to own signalling pointThis procedure describes how to add a local or remote SCCP signalling point and/or local or remote SCCP subsystems to the own signalling point.

Before you startBefore you can carry out this procedure, you have to know the signalling point code of the local or remote signalling point and the name of the local or remote subsystem to be added.

g The signalling point has to be defined on the MTP level, before it can be added to the SCCP configuration.

Steps

1 Check existing SCCP signalling points and subsystems (NFI and NFJ)

• To output the defined SCCP signalling point, use the following command:ZNFI:;

• To output the defined SCCP subsystems, use the following command:ZNFJ:;

2 Define SCCP signalling point and needed subsystems if needed (NFD)If the SCCP signalling point is already defined in the own signalling point and you only want to add new subsystems, continue with the next step.

With the following command you can define the new SCCP signalling point and up to 5 subsystems in it.

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ZNFD:<signalling network>,<signalling point code>,<signalling point parameter set number>:<subsystem number>,<subsystem name>,<subsystem parameter set number>,Y;

3 Add local or remote subsystems to own signalling point (NFB)ZNFB:<signalling network>,<signalling point codes>:<subsystem number>,<subsystem name>,<subsystem parameter set number>,Y;

4 Activate defined SCCP signalling point if needed (NGC)When you have defined a new SCCP signalling point, you have to activate it before you can activate the new SCCP subsystems.

ZNGC:<signalling network>,<signalling point codes>:ACT;

5 Activate defined SCCP subsystems (NHC)ZNHC:<signalling network>,<signalling point codes>:<subsystem>:ACT;

7.4 Removing SCCP signalling point and/or subsystem from own signalling pointBefore you startBefore you can carry out this procedure, you have to know the signalling point code of the local or remote signalling point and the name of the local or remote subsystem to be removed.

Steps

1 Check existing SCCP signalling points and subsystems (NFI and NFJ)To output the defined SCCP signalling point, use the following command:

ZNFI:;

To output the defined SCCP subsystems, use the following command:

ZNFJ:;

2 Deactivate the SCCP subsystems that you want to remove (NHC)ZNHC:<signalling network>,<signalling point codes>:<subsystem>:INA;

3 Remove local or remote subsystems from the own signalling point (NFT)ZNFT:<signalling network>,<signalling point codes>:<subsystem number>;

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4 Deactivate the SCCP signalling point that you want to remove if needed (NGC)You have to deactivate all subsystems before you can deactivate the SCCP signalling point.

ZNGC:<signalling network>,<signalling point codes>:INA;

5 Remove the local or remote SCCP signalling point from the own signalling point if needed (NFR)ZNFR:<signalling network>,<signalling point codes>;

7.5 Modifying the values of SCCP subsystem parameter setThis procedure describes how to create a new SCCP subsystem parameter set or how to modify the SCCP subsystem parameters in an existing SCCP subsystem parameter set.

The parameters in an SCCP subsystem parameter set define the SCCP subsystem sig-nalling functions of the own SCCP subsystems and/or the SCCP subsystem signalling functions towards remote SCCP subsystems. You can create several SCCP subsystem parameter sets for different types of signalling needs.

Before you startBefore changing the values of an existing SCCP subsystem parameter set, make sure that the change will not cause any malfunctions in the signalling system.


Steps

1 Check SCCP subsystems and the parameter sets they use (NFJ)As the modification of the values of an existing SCCP subsystem parameter set affects all the SCCP subsystems using that parameter set, consider if this can be done. If you want only a certain group of SCCP subsystems to have different values in the SCCP subsystem parameters, create a new SCCP subsystem parameter set and attach it to those SCCP subsystems.

You can output all known SCCP subsystems and the SCCP subsystem parameter sets they use with the following command:

ZNFJ;

If you want to create a new SCCP subsystem parameter set, see the procedure of Creating new SCCP subsystem parameter set.

2 Modify values of SCCP subsystem parameter set (OCN)ZOCN:<subsystem parameter set number>,<subsystem parameter set name>:<parameter number>,<parameter value>;

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7.6 Creating new SCCP subsystem parameter setThis procedure describes how to create a new SCCP subsystem parameter set or how to modify the SCCP subsystem parameters in an existing SCCP subsystem parameter set.

The parameters in an SCCP subsystem parameter set define the SCCP subsystem sig-nalling functions of the own SCCP subsystems and/or the SCCP subsystem signalling functions towards remote SCCP subsystems. You can create several SCCP subsystem parameter sets for different types of signalling needs.

Before you startBefore changing the values of an existing SCCP subsystem parameter set, make sure that the change will not cause any malfunctions in the signalling system.


Steps

1 Check SCCP subsystems and the parameter sets they use (NFJ)As the modification of the values of an existing SCCP subsystem parameter set affects all the SCCP subsystems using that parameter set, consider if this can be done. If you want only a certain group of SCCP subsystems to have different values in the SCCP subsystem parameters, create a new SCCP subsystem parameter set and attach it to those SCCP subsystems.

You can output all known SCCP subsystems and the SCCP subsystem parameter sets they use with the following command:

ZNFJ;

If you only want to modify the values of a certain SCCP subsystem parameter set, see the procedure of Modifying the values of SCCP subsystem parameter set.

2 Copy existing SCCP subsystem parameter set with a new name (OCF)The best way to create a new SCCP subsystem parameter set is to copy an old param-eter set with a new name. Choose the best suitable parameter set to be the source parameter set.

ZOCF:<source subsystem parameter set number>,<source subsystem parameter set name>:<subsystem parameter set number>,<subsystem parameter set name>;

3 Modify values of the new SCCP subsystem parameter set (OCN)ZOCN:<subsystem parameter set number>,<subsystem parameter set name>:<parameter number>,<parameter value>;

4 Inactivate the SCCP subsystem in which you want to use the created parameter set (NHC)ZNHC:<signalling network>,<signalling point codes>:<subsystem>:INA;

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5 Change the parameter set of the SCCP subsystem (NFM)Replace the existing parameter set of the SCCP subsystems with the new SCCP sub-system parameter set.

ZNFM:<signalling network>,<signalling point code>:<subsystem numbers>:<subsystem parameter set number>;

6 Activate the SCCP subsystem in which you want to use the created parameter set (NHC)ZNHC:<signalling network>,<signalling point codes>:<subsystem>:ACT;

Further information

Example: Creating new SCCP subsystem parameter setWith the following example, you can create a new SCCP subsystem parameter set with the name MIKA (number 4) by copying the existing parameter set number 0 (GENER). First, change the value of parameter 2 (timer Q714_T_IGN_SST) to be 70 s. Then, change the own SCCP signalling point to use this parameter set towards subsystem number 06 (MAPH) located signalling point 300 in signalling network NA0.

1. Check the SCCP subsystems and the parameter sets they use.ZNFJ;

2. Copy an existing SCCP subsystem parameter set with a new name.ZOCF:0,:4,MIKA;

3. Modify the values of the new SCCP subsystem parameter set.ZOCN:4,:,70;

4. Inactivate the SCCP subsystem in which you want to use the created parameter.ZNHC:NA0,300:06:INA;

5. Change the parameter set of the SCCP subsystem.ZNFM:NA0,300:06:4;

6. Activate the SCCP subsystem in which you want to use the created parameter set.ZNHC:NA0,300:06:ACT;

7.7 Setting and modifying broadcasts of local SCCP subsys-temThis procedure describes how to set the broadcast status of SCCP subsystems.

There are two different kinds of broadcasts you can set:

• local broadcast status (OBC command): it is used to inform the SCCP subsystems of the own signalling point about changes in the SCCP subsystems of the remote signalling points.

• broadcast status (OBM command): it is used to inform other signalling points about changes in the SCCP subsystems of the own signalling point or the SCCP subsys-tems of the signalling points connected to the own signalling point.

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Before you startWhen setting broadcasts, consider carefully what broadcasts are needed. If the broad-casts are set wrong or there are needless broadcasts, it can set the alarm 2247 or cause unnecessary traffic in the signalling network.

Steps

1 Interrogate existing broadcasts (OBL, OBI)ZOBL:;

ZOBI:;

2 Set local broadcast status (OBC)ZOBC:<network of affected subsystem>,<signalling point code of affected subsystem>,<affected subsystem number>:<network of local subsystem>,<local subsystem number>:<status>;

3 Set broadcast status (OBM)ZOBM:<network of affected subsystem>,<signalling point code of affected subsystem>,<affected subsystem number>:<network of concerned signalling point>,<concerned signalling point code>:<status>;

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Id:0900d80580373ce4Confidential

Monitoring signalling network objects

8 Monitoring signalling network objectsFollow the steps below to interrogate signalling network objects.

8.1 Interrogating SS7 network configuration and signalling route set stateWith this procedure, you can output the created objects of the signalling network and check the states of the created signalling route sets. In the output you can check created signalling route sets, signalling link sets, signalling links, and their states.

Steps

1 Interrogate SS7 network configuration (NET)To interrogate signalling network configuration, give the following command:

ZNET:;

OR

2 Interrogate signalling route set states (NER)To interrogate all created signalling route sets, give the following command:

ZNER:;

8.2 Interrogating and modifying signalling route stateWith this procedure, you can check and modify the states of the created signalling routes.

Steps

1 Interrogate signalling route states (NVI, NRI)To interrogate the states of all signalling routes in a given signalling network, give the following command:

ZNVI:<signalling network>,;

To interrogate the signalling points in a given signalling network and the signalling routes leading to them, give the following command:

ZNRI:<signalling network>,;

2 Change the state of signalling route, if needed (NVC)ZNVC:<signalling network>, <signalling point code>: <signalling transfer point network>, <signalling transfer point code>: <state change>;

8.3 Interrogating signalling link set stateWith this procedure, you can check the states of the created signalling link sets.

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Common Channel Signalling (MTP, SCCP and TC) Monitoring signalling network objects


Steps

1 Interrogate signalling link set states (NES)To interrogate the states of all signalling link sets, give the following command:

ZNES:;

2 Changing the state of signalling link set, if neededYou cannot directly change the state of a signalling link set by any commands. The sig-nalling link set state depends on the state of the signalling link in that signalling link set.

8.4 Interrogating and modifying signalling link stateWith this procedure, you can check and modify the states of the created signalling links.

Steps

1 Interrogate signalling link states (NEL, NLI)To interrogate the states of all signalling links, give either of the following commands:

ZNEL:;

ZNLI:;

2 Change the state of signalling link, if needed (NLC)ZNLC:<signalling link numbers>, <state change>;

8.5 Interrogating MTP level load sharing and MTP level STP traffic restrictionsWith this procedure, you can check the current settings of MTP level load sharing defined in an own network element and the current settings of MTP level STP traffic restrictions.

Steps

1 Interrogate MTP level load sharing (NEO)You can limit the output by giving appropriate values for the parameters of the command.

To interrogate MTP level load sharing, give the following command:

ZNEO:<signalling network>, <destination point codes>: SLS=<SLS range>, LINK=<SLS output>: <message originator>;

2 Interrogate MTP level STP traffic restrictions (NEP)You can limit the output by giving appropriate values for the parameters of the command.

To interrogate the MTP level STP traffic restrictions, give the following command:

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ZNEP:<authorizing method>: <signalling network>, <incoming direction signalling point code>, <destination point code>;

8.6 Interrogating and modifying SCCP signalling point stateWith this procedure, you can check and change the states of the created SCCP signal-ling points.

Steps

1 Interrogate SCCP signalling point states (NGI)You can limit the output by giving appropriate values for the parameters of the command.

To interrogate the SCCP signalling point states, give the following command:

ZNGI:<signalling network>, <signalling point codes>: <display mode>;

2 Change the state of SCCP signalling point, if needed (NGC)ZNGC:<signalling network>, <signalling point codes>: <state change>;

8.7 Interrogating and modifying SCCP subsystem stateWith this procedure, you can check and change the states of the created SCCP subsys-tems.

Steps

1 Interrogate SCCP subsystem states (NHI)You can limit the output by giving appropriate values for the parameters of the command.

To interrogate the SCCP subsystem states, give the following command:

ZNHI:<signalling network>, <signalling point codes>: <subsystem>;

2 Change the state of SCCP subsystem, if needed (NHC)ZNHI:<signalling network>, <signalling point codes>: <subsystem>: <state change>;

8.8 Interrogating SCCP subsystem broadcast statusWith this procedure, you can check the local and remote SCCP subsystems' broadcast status.

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Common Channel Signalling (MTP, SCCP and TC) Monitoring signalling network objects


Steps

1 Interrogate local SCCP subsystem broadcast status (OBL)You can limit the output by giving appropriate values for the parameters of the command.

To interrogate the local SCCP subsystem broadcast status, give the following command:

ZOBL:<network of affected subsystem>, <signalling point code of affected subsystem>, <affected subsystem number>: <network of local subsystem>, <local subsystem number>: <mode>;

2 Interrogate remote SCCP subsystem broadcast status (OBI)You can limit the output by giving appropriate values for the parameters of the command.

To interrogate the remote SCCP subsystem broadcast status, give the following command:

ZOBI:<network of affected subsystem>, <signalling point code of affected subsystem>, <affected subsystem number>: <network of concerned signalling point>, <concerned signalling point code>: <mode>;

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9 SS7 troubleshootingThis section lists the most common signalling network related problems that may occur during the use of the signalling network or when configuring the signalling network.

In general, if something goes wrong or is not working all right, you should first check the alarms currently on and refer to the instructions of each alarm.

9.1 Signalling link stays in state UA-INSWhen a signalling link is activated after its creation there may be some problems due to erroneous network configuration, erroneous link parameters, faulty hardware or some combination of these.

If a signalling link has been created and attached to the correct signalling route set and the state of the link continues to be UA-INS even after the activation commands, check first the basic configuration: the time slot of the PCM, the SLC values from both ends of the signalling link, the state of the AS7, the state of the ET.

Note that when a signalling link has been created between a MSC and a BSC there is a transcoder on the PCM. If there are problems on that transcoder, it may cause failures to links connected to it. Check the condition of the transcoder, if all links connected through it fail at the same time.

If all signalling links within the network element are in UA-INS state, the signalling point restart procedure is performed after the first link has been aligned. During that procedure the user cannot give any state changing commands. The MML replies that the state has not been changed. If the signalling point restart procedure takes more than two minutes, there might be some failures in link activations by the system.

You can avoid this kind of restart loop by connecting the ET to a loop (by connecting the ET's output to the ET's input) and then trying to activate the link connected to the ET. When an ET is connected to a loop, the signalling link testing has to be denied. If one link in the network element can be activated, it is much easier to find out reasons for unavailabilities of other links.

Steps

1 Check that there is a service defined for signalling link test messages (NPI)The service needed for the SLTM is SNT (for ITU network) or SNTA (for ANSI network).

ZNPI:<network indicator>;

To define new services, use the NPC command.

2 Check that SLC (signalling link code) is set to the same value at both ends of the link, and check that the signalling point codes and network indicator are correct (NSI)Use the NES or NSI commands to check the values used in your own network element and contact the holder of the remote network element to find out the values used in the remote network element.

ZNSI:<network indicator>,<sp code>;

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Common Channel Signalling (MTP, SCCP and TC) SS7 troubleshooting


3 Check signalling link test status (NSI)Note that the link test state should always be LINK TEST ALLOWED. If the link test state is LINK TEST NOT ALLOWED, the link can be activated, even if it has been configured erroneously. Then, even if the state of the signalling link is AV-EX, it may be unable to transmit any traffic. You can check the state with the following command.


If the state is LINK TEST NOT ALLOWED, set the testing state LINK TEST ALLOWED. The reasons for unavailability are shown in alarms.

ZNST:<network indicator>,<sp code>,<link set name>: <link test status>;

4 Check if the system has set the alarm 2069 (signalling link test failed) (AHO) ZAHO::NR=2069;

If the alarm 2069 is set, see the alarm instructions.

5 Check if the system has set the alarm 2072 (AHO)The alarm is set if signalling link activation does not succeed in two minutes.

ZAHO::NR=2072;

If the failure code of the alarm is 3 (initial alignment not possible), see the instructions for alarm 2072.

6 Try to locate whether the fault is inside the switch or in the transmissionLoop the signalling link from the exchange terminal (ET) with a loop connector or, if it is possible, loop the signalling link time slot (digital time slot based cross-connector). Before that, deny the signalling link test by using the NST command, because the sig-nalling link test cannot handle looped links.

7 Check if system has set alarm 2079 (loop test failed in signalling link terminal) (AHO)ZAHO::NR=2079;

If there is no alarm 2079, but the signalling link is not aligning in the loop, the fault lies between the group switch and the exchange terminal. Check the cabling.

If link activation succeeds in the loop, check the transmission path.

9.2 Failures in the signalling link terminalIf the system has generated an alarm, or if you suspect a failure in a signalling link terminal (AS7), follow these instructions.

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Steps

1 Activate the back-up unitIn case a back-up unit has been configured for the failed signalling unit type (CCSU, BSU, BCSU, etc.) on the network element, engage the spare unit by setting the failed unit in spare state (SP-EX) — if the system has not already transferred the unit into test state (SP-TE). This activates the spare unit into state WO-EX and it can then take over the tasks of the failed unit.

Use this command to set signalling link terminal CCSU-1 to state SP-EX:

ZUSC:CCSU,1:SP;

If there is no back-up unit, continue from the next step. A missing back-up unit results in a decrease in the capacity of the network element.

2 Check whether the terminal is faulty by submitting it to diagnosticsTo run the diagnostics on the signalling link terminal you suspect to be faulty, set the terminal into test state (SP-TE), if the system has not already set the test state, with this command:

ZUSC:CCSU,1:TE;

If the diagnostics show that the terminal is not faulty, try to activate it again or leave it as the back-up unit. If the terminal is faulty, replace it with a new one.

3 Replace the faulty signalling link terminal

fWhen you handle the plug-in units, remember to protect them from static electricity and wear a resistive wrist wrap or a similar purpose grounding device. The components of the plug-in units or other units may be damaged by electrostatic discharge. Avoid touching the contacts and connector surfaces.

Pay attention to these matters when changing a faulty signalling link terminal:

• The interchangeability of a plug-in unit affects the strappings. If the interchangeabil-ity remains the same, the strappings can be copied from the old plug-in unit. Other-wise, always check the settings from the instrictions for strappings. The interchangeability code is marked on a sticker on the outer edge of the plug-in unit.

• When the location of the plug-in unit remains the same in a CCSU or a similar unit, you can copy the location related strappings from the failed plug-in unit. The location may have to be changed if the type of the signalling link terminal needs to be changed, for example, if several 1-channel AS7-S terminals are replaced by one 4-channel AS7-U terminal, or vice versa.

• You can use the WTI command to check whether the strappings have succeeded. The command reports the slot where the plug-in unit is located, and its base address; check that they are correct and in accordance with the settings you defined.

• A failure in the signalling link terminal can result in a need for a new signalling unit since it is not possible to define back-ups for the signalling plug-in units in the sig-

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nalling units (CCSU, BSU, BCSU, etc.). If you have to remove a plug-in unit from a signalling unit, remember to deactivate the unit before pulling it out from the slot. Otherwise, the system interprets the disappearance of the plug-in unit as a fault in the active unit, and this results in a changeover, and some signalling messages are possibly lost because the data on the sent and acknowledged messages stored on the removed plug-in unit disappears. We strongly recommend that all changes of plug-in units are performed using the appropriate commands, so that the signalling management programs transfer the signalling traffic in a controlled manner to another signalling unit.

• The strappings on the plug-in unit are always independent of the CCS user part. The same plug-in unit can serve all the CCS user parts at the same time.

g When you remove a faulty plug-in unit from service, take care to mark it clearly so that it will not by mistake be put back in operation before it has been checked and repaired.

After a faulty unit has been repaired, you may want to activate it as a back-up unit. The original back-up unit is set as the active operating unit, and so the back-up unit in the network element has been changed. You can resume the original situation if necessary. This is done by setting the state of the original back-up unit as SP-EX (spare) and then the original active unit resumes active working state (WO-EX). The state changes are carried out using the USC command.

As the user you can always change the operating unit by changing the state of the active unit from working to spare, which results in the back-up unit taking over the tasks.

More detailed information on fault localization, diagnostics and change of plug-in units is available in Instructions for Replacing Plug-in Units.

9.3 Signalling route goes to or stays in state UA-INRSteps

1 Find out the states of adjacent and destination signalling pointsState UA-INR means that the signalling route is unavailable because the adjacent sig-nalling point has sent a transfer prohibited signal (TFP) to the local signalling point con-cerning the destination point.

Either the adjacent signalling point has no access to the destination point or the route defined to the destination point goes through the signalling point that has sent the message.

The routes that are in UA-INR state are periodically tested with route set test messages (RST). If TFA (transfer allowed) message is received as a reply to the RST, the route is considered available. The route can temporarily be in the state UA-INR even when there is no particular fault in the configuration or hardware.

If the route is often in this state, the reason has to be cleared with the holder of the adjacent signalling point.

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9.4 Signalling link fails occasionally or there is an unexpected reset of AS7Steps

1 Check if system has set alarm 1072 (AHO)ZAHO::NR=1072;

See instructions for the alarm 1072 for more detailed info about the reason for the failure.

2 Interrogate signalling link terminal meters (OMT)ZOMT:LINK=<link number>:A,Z;

OR

3 Check the alarm 2075Check the alarm 2075 for more detailed information about the reasons for the failure and follow the instructions.

9.5 Signalling link is in state UA-INSThere are different reasons why the initial alignment or the test procedure might fail. The reasons should be checked out.

Steps

1 Check that the signalling link has created a unique combination of unit, logical unit, terminal, terminal function and logical terminal (NEL)The unit defines the actual unit where the signalling link is situated. One unit should not contain the same logical terminal number twice. The terminal and the terminal function define the unique combination of hardware serving as one logical terminal and thus serving one signalling link. There should not be two similar combinations of terminal and terminal function in one unit. It is important to check that the external PCM-TSL and internal PCM-TSL are correct. Check all this with the command NEL.

If the terminal and terminal function fields in the execution printout are empty, it means that for some reason the terminals have not sent initialisation requests. In this case you should check that there is an adequate number of signalling terminals defined in the units. You can check this by using the WTI command.

If the terminal sends initialisation requests but you get additional information in the output that the signalling terminal has not been initialised, then the internal PCM-TSL is missing from the configuration database. You can check this with the WTI command.

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2 Check that the internal PCM-TSL belongs to int_st7_route and external PCM-TSL belongs to ext_st7_route (RCI)To check that the internal PCM-TSL belongs to int_st7_route and external PCM-TSL belongs to ext_st7_route, use the RCI command. Numbers of the routes can be checked from internal routing parameters with the NMI command.

3 Check alarms (AHO)Check that there are no alarms concerning the signalling link in question.

Especially check the following alarms:

• 1072 SIGNALLING LINK OUT OF SERVICE • 2069 SIGNALLING LINK TEST FAILED

• 2079 LOOP TEST FAILED IN SIGNALLING LINK TERMINAL

If any of these alarms are set on, follow the alarm instructions.

4 Contact Nokia Siemens Networks Customer Service

9.6 Signalling link activation succeeds but traffic failsSteps

1 Check that all network items are in state AV (available) (NVI, NSI, NLI, NLC)Check the states of the signalling route set and signalling route by using the command:

ZNVI:<network indicator>,<sp code>;

Check the state of signalling link set by using the command:


Check the state of signalling link by using the command:

ZNLI:<link numbers>;

If the link state is not AV-EX try to activate it with the NLC command.

ZNLC:<link number>,ACT;

2 Check traffic distribution (NEO)ZNEO:<network indicator>,<sp code>;

The load sharing between links within the link set should be as even as possible. If one or more links have much more SLS codes than other links, or if there are some links in the link set in the active state, but with no place in the load sharing table, the load sharing has been corrupted.

One way to fix the load sharing table is to change the states of some links in the link set. The load sharing algorithm tries to spread SLS values evenly to all links.

ZNLC:<link number>,INA;

ZNLC:<link number>,ACT;

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3 Check that there are services defined for all necessary user parts (NPI)ZNPI:<network indicator>;

Create missing services with the NPC command.

4 Check if the system has set the alarm 2224 (AHO)ZAHO::NR=2224;

If the alarm 2224 is set, follow the alarm instructions.

9.7 All MTP and SCCP level objects are in state available (AV) but location update fails or mobile calls are cut frequently after 4.5 minSteps

1 Check that the SCCP service is defined on MTP level in all needed signalling networks (NPI)ZNPI:<signalling network>;

Create the missing service with the command NPC.

OR

2 Check the values of SCCP timer parameters Q714_T_IAR and Q714_T_IAS from both MSC and BSC sites (OCI)ZOCI:<signalling point parameter set numbers>;

The timers that are used for certain direction are defined in the signalling point parame-ter set of the remote node. If the timer Q714_T_IAR of one node (typically 4.5 min) is shorter that the Q714_T_IAS of the remote node, SCCP signalling connections will be released after Q714_T_IAR.

Change the Q714_T_IAR timer value in the own node to be greater than the Q714_T_IAS timer value in the remote node with the OCM command.

9.8 Global title translation fails although translation exists and the global translation resultSteps

1 Check that the header information of GT translation is the same as the one used in the addresses (NBI)ZNBI:;

Check that not only the digits are matching but also the following values correspond to the needed translation:

• global title indicator (ITU-T or ANSI) • translation type

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• numbering plan • nature of address indicator.

To modify the values, first you have to delete the existing analysis with the NBD command, and then create a new analysis with the correct values with the NBC command. .

OR

2 Check that a translation result exists for each global title (NAI)ZNAI;

Check that a translation result (GTRFIL record) exists for each global title to be trans-lated and that they contain the required data.

Note that one translation result may serve several global titles.

3 Confirm that the network and the destination point code (DPC) are the required onesNote that you cannot create a global title result where the DPC is unknown to the SCCP and you cannot delete the DPC from the SCCP if it has been attached to the global title result.

4 Check the RESULT STATE fieldThere are two possible values ACT (active) and INA (inactive). The normal state of the global title result is active and it is in this state after creation. If the result state is inactive, the global title result is out of service and it should not be used for routing. You can change the state with the NAM command.

5 Check that the routing indicator (RI) setting is appropriate for the desired routingIf RI is SSN (route-on-label) there should be no reference to global title modification data record number (GTM). If RI is GT (route-on-gt), then GTM is optional.

6 Check the subsystem number, SSNIf the subsystem number (SSN) is included in the result, all outgoing messages will also contain this new SSN. New subsystem numbers replace the original subsystem numbers fetched from the called address and the original subsystem has no effect on this.

7 Confirm that the subsystem translation is as required and check the validity of the indicated SSN

8 Check the global title modification data (NAX)If a global title modification data record number (GTM) exists in the result, check the global title modification data using the GTM as a parameter in the NAX command.

ZNAX:DN=;

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The global title data (GTMFIL) is used to change or replace the global title that is being translated (e.g. delete/add digits or replace the header information). Check the validity of each change, as represented in the displayed data, against the requirements for translation. Check also that each listed global title data record is referenced by a trans-lation result record (GTRFIL record).

Note that when the global title number is changed, it is analysed again during the routing procedure. This means that the global title analysis for the modified global title number should also exist.

Further information

Example: Checking GT translation resultIn this example we have an existing digit string 123456 in a global title. The global title translation result contains modification record number 00001. In GTMFIL record is ADC=2 (add digits count), ADP=5 (add digits pointer) and DIGITS=99 (digits to be added). This will add digits 99 just in front of the fifth digit in the original digit string. The resulting digit string is then 12349956.

Example: Checking GT translation resultIn this example we have an existing digit string 123456 in a global title. The global title translation result contains modification record number 00002. In GTMFIL record is DDC=1 (delete digits count) and DDP=5 (delete digits pointer). This will delete the fifth digit from the original digit string (number 5), and the resulting digit string is 12346.

Example: Checking GT translation resultIn this example we have an existing digit string 123456 in a global title. The global title translation result contains modification record number 00003. In GTMFIL record is DDC=1 (delete digits count), DDP=5 (delete digits pointer), ADC=2 (add digits count), ADP=5 (add digits pointer) and DIGITS=99 (digits to be added). This will delete the fifth digit from the original digit string (number 5) and add digits 99 just in front of the fifth digit in the ORIGINAL digit string. The resulting digit string is then 1234996.

Example: Checking GT translation resultIn this example we have the header information in a global title: SS7 standard = ITU, GTI = 4, TT = 0, NP = 1 and NAI = 4. The global title translation result contains modifi-cation record number 00004. In GTMFIL record no digit modification is made, but the NP (numbering plan) is different from the one in the original global title. This will replace the header information so that the NP is changed (new NP = 7). Digits remain unchanged.

Example: Example modification records as seen in the MML execution printoutsGTMFIL DIGITSRECORD SS7 GTI ENC TT NP NAI DDC DDP ADC ADP 123456789012345------ ---- --- --- --- --------- -------- --- --- --- --- --------------- 00001 ITU 4 BCD 000 1 (E.164) 4 (INT.) - - 2 5 99 00002 ITU 4 BCD 000 1 (E.164) 4 (INT.) 1 5 - - 00003 ITU 4 BCD 000 1 (E.164) 4 (INT.) 1 5 2 5 99 00004 ITU 4 BCD 000 7 (E.214) 4 (INT.) - - - -

To check the references from the translation results (GTRFIL) use the NAX command, where parameter RN means referenced global title modification data record number.

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For each global title to be translated, check that there is a number analysis, so that the intended translation result (GTRFIL record index) can be reached. Note that not all digits in the global title are used in the analysis, but only those needed to reach the intended translation result. This can be done with the NBI command where you can give the header information, digits and result record indexes.

9.9 State of all subsystems in the remote network element is unavailable (UA) although MTP route set is in state avail-able-executing (AV-EX)Steps

1 Check the state of the remote SCCP (NGI)ZNGI:;

2 Change the state to AV, if necessary (NGC)If the SCCP of the remote node is in state UA-INU, change the state to AV with the fol-lowing command:

ZNGC:<signalling network>,<signalling point code>:ACT;

9.10 Some remote subsystems do not recover after route set unavailabilitySteps

1 Check the defined subsystemsCheck that the defined subsystems exist in the remote network element and whether they should exist. This means for example checking whether the remote network element should only be used as a signalling transfer point (STP), or whether the subsys-tems in question should exist there.

If the subsystems should exist, the reason for unavailability could be temporary, caused by changes in configuration or a fault situation. If the subsystems really are down (unavailable) in the remote network element, you cannot bring them up from your local network element.

Depending on who the remote network element belongs to, this kind of matters should be considered in the appropriate forum, for example in negotiations between operators.

9.11 A signalling point parameter or a subsystem parameter does not take effect as describedTo find out the problem, check the item (signalling point or subsystem), which the parameter set applies to.

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Steps

1 Check the parameter set of the SCCP signalling point (NFI)Use the NFI command to check which parameter set the SCCP signalling point uses.

OR

2 Check the parameter set of the SCCP subsystem (NFJ)Use the NFJ command to check which parameter set the SCCP subsystem uses.

OR

3 Check the values of the SCCP signalling point parameter sets (OCI)Use the OCI command to interrogate the values of the SCCP signalling point parameter sets.

OR

4 Check the values of the SCCP subsystemn parameter sets (OCJ)Use the OCJ command to interrogate the values of the SCCP subsystem parameter sets.

9.12 After updating DX software, the SCCP of own signalling point is in state unavailable (UA), although everything else is in state available (AV)Steps

1 Check if the whole ISSTAB file is filled with FF (DFD)ZDFD:CCSU,0:523;

If the whole file is filled with FF it means that the file ISSTAB has not been copied from the previous software build.

2 Copy the old ISSTAB file, if necessary (DEM)Use the DEM command to copy the old ISSTAB file.

9.13 TC sends an abort message with error code 03 "Incorrect transaction portion" to the received dialogue requestTypically the situation occurs when the originating side is trying to set up a dialogue with application context negotiation, and the destination side TC does not support the message structure (i.e. application context fields) defined in the White Book. The origi-nating side application should be able to start a new dialogue without the application context.

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Steps

1 Change the originating side configurationIf the application does not adapt to the situation, try to change the originating side con-figuration in such a way that the TC user does not use application context in the BEGIN message (the command group RG if the application is INAP, or the command group OP in case of MAP).

Further informationThe White Book TC enables the TC users to negotiate the application context to be used in the dialogue (see TC introduction). If the receiving TC does not support the White Book specifications and thus the dialogue portion information element (where the appli-cation context information is conveyed), the dialogue is aborted with the cause code "Incorrect transaction portion". Similarly, if the dialogue is started with the BEGIN message including the application context, and the responding message (END or CON-TINUE) does not include a dialogue portion information element (i.e. application con-text), the dialogue is aborted with the same cause code.

9.14 Large capacity signalling link creation or modification failsSteps

1 Check the error messages

Example: No free terminal in unit/*** NO FREE TERMINAL IN UNIT ***/

When this error message appears, check terminal types in the signalling unit with the WTI command. You are allowed to create/modify large capacity signalling links only for signalling terminal types AS7–V, AS7–VA, AS7–A, AS7–C and AS7–D.

Example: External PCM TSL is already used for another signalling link/*** EXTERNAL PCM TSL ALREADY USED FOR SIGNALLING LINK ***/

When this error message appears, check with the command NEL, if the time slots of the current external PCM are connected to another signalling link. Note that for a large capacity signalling link the reserved time slots have to be in consecutive order. Gaps within the time slot space are not allowed.

Example: No exchange terminal is determined for the signalling data link/*** NO EXCHANGE TERMINAL FOR SIGNALLING DATA LINK ***/

When this error message appears, check the <PCM-TSL> parameter of the given command. Check the state of the ET unit with the USI command. The number of the ET has to be the same as the number of the PCM.

Example: Signalling link activation is not denied/*** SIGNALLING LINK ACTIVATION NOT DENIED ***/

The activation of the signalling link has to be denied before the link data can be modified. Deny the signalling link activation with the command NLD.

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9.15 Allowing of link activation and initialisation of signalling terminal failSteps

1 Initialise the signalling terminal unitThe signalling link cannot be activated before the signalling unit is initialised.

SIGNALLING UNIT SWITCHOVERIS REQUIRED BEFORE LINK CAN BE ACTIVATED

Initialise the signalling terminal unit by signalling unit switchover or restart the unit.

OR

2 Check if there are free signalling terminals in the unitNO FREE SIGNALLINGTERMINALS IN UNIT

In the case of a large capacity signalling link, this error text occurs typically after signal-ling unit switchover, when there is not enough terminal capacity in the spare unit to support a large capacity signalling link.

Check that both ends of the signalling link have the same link bit rate. See Bit rates of the signalling links in the same link set.

Check that both ends of the signalling link use the same time slots of the external PCM, use the NEL command. If they are different, Modify the data of the signalling link.

Check that both ends of the signalling link use the same SLC within the signalling link set, use the NSI command.

If the state of the signalling link is UA-INS, check the current alarms with command AHO. If notice 1072 SIGNALLING LINK OUT OF SERVICE occurs then follow the alarm instructions.

9.16 Activation of large capacity signalling link failsSteps

1 Check signalling terminal unitsCheck that there are signalling terminal units supporting large capacity signalling links (AS7–V, AS7–VA, AS7–A, AS7–C or AS7–D) at both ends of the signalling link.

2 Check the external information of the signalling link (NEL)Check the external information of the signalling link with the NEL command. Check the output of the NEL command for error messages, see the following examples.

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Example: The signalling link cannot be activated before the signalling terminal has been initialisedThe signalling link cannot be activated before the signalling terminal has been initialised. If the signalling unit has not been initialised, the system outputs the following error message:

SIGNALLING UNIT SWITCHOVERIS REQUIRED BEFORE LINK CAN BE ACTIVATED

Initialise the signalling terminal by signalling unit switchover or by restarting the unit.

As a default a signalling terminal unit AS7–V, AS7–VA, AS7–A, AS7–C or AS7–D is ini-tialised so that all signalling links within the signalling terminal are set to run as 1 time slot link 56kbit/s or 64 kbit/s. If in the signalling unit there are any large capacity signal-ling links, signalling link terminal is set to work with multi time slot link by terminal initial-isation. All free resources of the signalling terminal units are initialised for 1 time slot link.

g Signalling unit restart causes disturbances for signalling traffic. The links that have been connected to the current signalling unit will be cut during restart.

When the user inquires the data of the signalling link or creates/modifies a signalling link, the system checks whether it is possible to activate the signalling link. If there are free resources for the signalling link in the signalling unit, the system checks the type of those free resources (internal time slots of internal PCM). Check with the WTI and RCI com-mands. The resourses might be free but initialised for the wrong type (bit rate) of signal-ling link. The free resources of the wrong type can be taken into use for other types of signallink links after terminal initialisation.

Example: There are no free signalling terminals in the unitNO FREE SIGNALLINGTERMINALS IN UNIT

The error texts occurs typically after signalling unit switchover when in the spare unit there are not enough terminal capacity giving support for large capacity signalling link.

Check that both ends of the signalling link have the same link bit rate. See .

Check that both ends of the signalling link use the same time slots of the external PCM, use the NEL command. If they are different, Modify the data of the signalling link.

Check that both ends of the signalling link use the same SLC within the signalling link set, use the NSI command.

If the state of the signalling link is UA-INS, check the current alarms with command AHO. If notice 1072 SIGNALLING LINK OUT OF SERVICE occurs then follow the alarm instructions.

9.17 Bit rates of the signalling links in the same link setSteps

1 Check the bit rate of the signalling links of the link set (NSI, NEL)If within signalling link set there are signalling links which have different bit rates this warning text is displayed:

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SIGNALLING LINKSWITHIN SIGNALLING LINK SET HAVE VARIOUS BIT RATE WHICH IS NOT NOTICED IN LOADSHARING

It is recommended that all signalling links within signalling link set have the same trans-mission capacity. If some of them have different capacity value it does not cause problems for the system. But the load sharing of signalling traffic within the link set does not notice it at all. The signalling load is shared between links evenly even one of the signalling links have bigger transmission capacity than other links.

The mixed transmission capacities within the link set have been allowed for modification purposes of signalling links. The user can modify the transmission capacity of the sig-nalling link of the existing signalling link set so that the signalling messages can be trans-mitted through other signalling links during modifications. Check the bit rate of the signalling links of the link set, use the NSI and NEL commands.

2 Modify the data of the signalling link (NLC, NLD, NCM, NLA, NLC)Modify the data of the signalling link with these commands:

NLC:<signalling link numbers>,<state change>;

NLD:<signalling link numbers>;

NCM:<signalling link number>:<external PCM-TSL>,<link bit rate>:<unit type>,<unit number>;

NLA:<signalling link numbers>;

NLC:<signalling link numbers>,<state change>;

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Common Channel Signalling (MTP, SCCP and TC) States of SS7 signalling network objects


10 States of SS7 signalling network objectsBy studying the states of the signalling network, you can, for example, monitor how the network is operating and find reasons for malfunctions. You can change the network operations by modifying the states of the network elements. When you modify the con-figuration of the signalling network, notice that it is usually possible to change the states in such a way that the signalling traffic is not interrupted.

10.1 States of signalling route setsThe state of a signalling route set depends on the states of the signalling routes included in the route set. The signalling route set has four states: available (AV), unavailable (UA), restricted (AR), and congested (CONG).

The signalling route set is available (in state AV) when one or more of its signalling routes are available, that is, they can be used by signalling traffic. The route set is unavailable (in state UA) when all its routes are out of service. The state of the route set changes automatically to AV when the first signalling route proves to be available.

The signalling route set is congested (in state CONG) if the signalling link on the active route is overloaded. The signalling route set assumes the state CONG if a signalling point on the route receives a 'transfer controlled' message (TFC) that concerns the sig-nalling point served by the route set. Time supervision takes care of changing the state automatically into AV when the overload situation is over.

You can use the NER command to interrogate the states of the signalling route sets.

10.2 States of signalling routesYou can define both main states and substates for a signalling route. The main state indicates whether the route is available (AV) or unavailable (UA). The substates give more information on the working state, for example, who has set the route and whether it is in spare state. By setting different working states, you can change the signalling traffic over to another signalling route without causing breaks in the traffic flow.

Main state - substate

Name of the state Meaning/reason

AV-EX available-executing The signalling route is transferring signalling traffic.

AV-SP available-spare The signalling route does not transfer signalling traffic but can be taken into use.

UA-INU unavailable-deactivated by user

User has deactivated the route.

UA-INS unavailable-deactivated by system

The system has deactivated the route./The signal-ling route is transferring signalling traffic.

UA-INR unavailable-deactivated by remote exchange

The remote end has deactivated the route./The sig-nalling route is transferring signalling traffic.

UA-AD unavailable-activation denied Activation of the route is denied./The signalling route is transferring signalling traffic.

Table 2 States of the signalling routes

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Available but restricted, AR This state is a parallel state for available (AV): in this state, the signalling route can transfer signalling traffic and it also has the substates executing (EX) and spare (SP) in service.

The state is possible only if the signalling route set uses the procedure 'transfer restricted' (for more information, see Section SS7 signalling network parameters). The signalling route which is in this state has received a 'transfer restricted' message from the transfer point, which lowers the priority of the route to some extent.

10.3 States of signalling link setsThe state of a signalling link set depends on the states of its links. The link set has two states: available (AV) and unavailable (UA).

The signalling link set is in state AV when at least one of the links included in the link set is available.

The link set is in state UA if all its links are in state UA. The state changes automatically into AV when one (or more) of the signalling links (included in the link set) assume state AV.

You can use the NES or NSI command to interrogate the states of signalling link sets.

10.4 States of signalling linksA signalling link has two main states: available (AV) and unavailable (UA). State AV has one substate and state UA can have one or two substates at the same time. .

AR-EX available but restricted-exe-cuting

See below.

AR-SP available but restricted-spare See below.


Name of the state Meaning/reason

Table 2 States of the signalling routes (Cont.)

Main state -substate 1 -substate 2

Name of the state Meaning and the change made

AV-EX available-executing Link is working normally.

UA-AD unavailable-activation denied Operator has taken the link out of use and has denied activation. See below.

UA-TST unavailable-testing User has started a data link test and only test traffic can be transferred through the link, while no signalling traffic is allowed.

UA-INU unavailable-deactivated by user Operator has taken the link out of use. To activate the link, use the NLC command.


System has taken the link out of use. Link has not completed the initial alignment or the signal-ling link test procedure successfully.

Table 3 States of the signalling links

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UA-BLU unavailable-blocked by user User has blocked the signalling link.

UA-BLR unavailable-blocked by remote exchange

Remote end exchange has blocked the signal-ling link, or there is a processor outage condition at the remote end.

UA-BLB unavailable-blocked by user and remote exchange

The signalling link has been blocked at both ends.

UA-IBL unavailable-inhibited local User has inhibited the link.

UA-IBR unavailable-inhibited remote Remote end has inhibited the link.

UA-IBB unavailable-inhibited local and remote

The signalling link is inhibited at both ends.

UA-INU-IBL unavailable-deactivated by user-inhibited local

User has deactivated and inhibited the signal-ling link.

UA-INU-IBR unavailable-deactivated by user-inhibited remote

User has deactivated and the remote end has inhibited the signalling link.

UA-INU-IBB unavailable-deactivated by user-inhibited local and remote

User has deactivated and inhibited and the remote end has inhibited the signalling link.

UA-INS-IBL unavailable-deactivated by system-inhibited local

System has deactivated and user has inhibited the signalling link.

UA-INS-IBR unavailable-deactivated by system-inhibited remote

System has deactivated and remote end has inhibited the signalling link.

UA-INS-IBB unavailable-deactivated by system-inhibited local and remote

System has deactivated and user has inhibited the signalling link at both ends.

UA-BLU-IBL unavailable-blocked by user-inhibited local

User has blocked and inhibited the signalling link.

UA-BLU-IBR unavailable-blocked by user-inhibited remote

User has blocked and remote end has inhibited the signalling link.

UA-BLU-IBB unavailable-blocked by user-inhibited local and remote

User has blocked the signalling link and the sig-nalling link is inhibited at both ends.

UA-BLR-IBL unavailable-blocked by remote exchange-inhibited local

The signalling link is blocked in remote end and user has inhibited the signalling link.

UA-BLR-IBR unavailable-blocked by remote exchange-inhibited remote

The signalling link is blocked and inhibited at remote end.

UA-BLR-IBB unavailable-blocked by remote exchange-inhibited local and remote

The signalling link is blocked at the remote end and inhibited by user at both ends.

UA-BLB-IBL unavailable-blocked by user and remote exchange-inhibited local

User has blocked and inhibited the signalling link and the remote end and has blocked the signalling link.

UA-BLB-IBR unavailable-blocked by user and remote exchange-inhibited remote

User has blocked the signalling link and the sig-nalling link is blocked and inhibited at remote end.



Table 3 States of the signalling links (Cont.)

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Inhibiting a signalling linkYou can inhibit the signalling link from the local end. After that the signalling link gets into state unavailable-inhibited local (UA-IBL). If you want to take the signalling link back into use, use the NLC command.

Signalling link inhibition means that the signalling link is inhibited from the signalling traffic of the user part but it can transfer maintenance and test messages. The inhibition does not cause any measures on level 2. It is taken care of by the signalling link control function on level 3. The inhibition is accepted only if it does not make any accessible destinations (signalling point) inaccessible at either end.

If a signalling link is in state unavailable-inhibited remote (UA-IBR), the operator of the exchange at the remote end of the signalling link has inhibited it. You cannot uninhibit such signalling links, but they can be taken into use by applying a system in case some signalling point would otherwise become inaccessible.

When the signalling link is inhibited at both ends, the state of the signalling link is unavailable-inhibited local and remote (UA-IBB). In this case you can change it to state UA-IBR by using the NLC command if you want to uninhibit it locally.

Blocking a signalling linkYou can block a signalling link. It means that the signalling link is set to processor outage state at the local end and no signalling messages are transferred over the link. In this case, the signalling link is in state unavailable-blocked by user (UA-BLU).

The signalling link can also be blocked at the remote end network element or at both ends. In this case the user of the remote end network element has blocked the signalling link which is in state'unavailable-blocked by remote (UA-BLR). This means that a pro-cessor outage condition exists at the remote end. If the signalling link has been blocked at both ends, the signalling link is in state unavailable blocked by user and remote (UA-BLB).

Signalling link in state UA-ADIf a signalling link is in state unavailable, activation denied (UA-AD), it means that the operator has taken it out of service and has denied its activation. Follow the steps below to activate the signalling link:

1. Use the NLA command to allow the activation of the link.2. Give the NLC command to activate the signalling link.

If a signalling link is in state unavailable deactivated by user (UA-INU) it means that the operator has taken it out of service. If the link is in this state, activate it by using the NLC command.

UA-BLB-IBB unavailable-blocked by user and remote exchange-inhibited local and remote

The signalling link is blocked and inhibited at both ends.



Table 3 States of the signalling links (Cont.)

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Signalling link in state UA-INSIf a signalling link is in state unavailable-deactivated by system (UA-INS), it means that the signalling link has not completed the initial alignment or the signalling link test pro-cedure successfully.

Signalling data link test procedureThe signalling link can be also in state Tested (TST). This means that the user has started a data link test and only test traffic can be transferred by the link, while no sig-nalling traffic is allowed. Before the user can place a link in state TST, the link must first be in state unavailable-activation denied (UA-AD). You can change the state with the NLD command. After that, you can define how to test the link by using the NLT command.

10.5 States of SCCP signalling pointsThe execution printouts can contain two states. The first one has two possible values: AV (available) and UA (unavailable). The normal state is always AV if a primary desti-nation point or the replicated destination point is available. The state of SCCP signalling point should normally follow the state of the signalling route set on the MTP level. The second state shows the state of an individual signalling point.

For instructions, see Section Activating SCCP configuration.

SCCP signalling point in state AV-CONGIn state available-congested (AV-CONG), the signalling point handles the signalling traffic while the signalling route set is in an overload condition. In an ANSI network, the messages have priorities and it is possible that a lower priority message routing has ter-minated due to this overload condition. In an ITU network, the AV-CONG state does not have much effect on the SCCP level, so it is for information only. If the state of signalling point is available-spare (AV-SP), the state of replicated signalling point is available and it is ready to handle traffic if the primary signalling point becomes unavailable.


Name of the state Meaning

AV-EX available-executing The SCCP signalling point transfers signalling traffic.

AV-SP available-spare The state of replicated signalling point is available and the point is ready to handle traffic if the primary signalling point becomes unavailable.

AV-CONG available-congested The SCCP signalling point transfers signalling traffic, while the signalling route set is in an overload condition.


The user has taken the SCCP signalling point out of service.


The system has taken the SCCP signalling point out of service because the signalling point is unavail-able on the MTP level.

Table 4 States of SCCP signalling points

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SCCP signalling point in state UA-INSIf the state of a signalling point is UA-INS, it has been set to inactive state by the system. This means that the route set on the MTP level has become unavailable and it should be verified.

SCCP signalling point in state UA-INUIf the state of a signalling point is UA-INU, it has been set to inactive state by the user and it can be taken into use by using the NGC command.

g The state of the signalling point is UA-INU when it is first created. Do not forget to change the state and take the SP into use after creation. Note also that the replicated signalling point is in state unavailable-user denied (UA-UD) when it is created. You can take the SCCP signalling point into use with the NGD command.

10.6 States of SCCP subsystemsThe local subsystem must be registered before it is allowed to use the SCCP services. The subsystem is in state AV-EX when it is registered. State UA-INU (set inactive by user) is the state when the local subsystem is created, and it should be activated using the NHC command. For instructions, see Section Activating SCCP configuration.

SCCP subsystem in state UA-INSIf the local subsystem is in state UA-INS, it has not been registered and no messages can be delivered to it. The subsystem registration situation can be checked with the NHJ command. You can see from the registration info if the subsystem is using a connection-oriented service, connectionless service, or local broadcast service. The FE subsystem

Main state-substate

Name of the state Meaning

AV-EX available-executing The subsystem is transferring signalling traffic.

AV-SP available-spare The subsystem is not transferring signalling traffic, but it can immediately be taken into use when nec-essary. This can be the case, for example, when there is a failure in the executing subsystem.


The user has taken the subsystem out of use.


The signalling point where the subsystem is located is unavailable.

UA-INR unavailable-deactivated by remote exchange

An SSP message is received or, alternatively, when the user is activating the signalling point, the signal-ling point does not respond to the subsystem state test message with an SSA message.

UA-UD unavailable-use of replica denied

Activation of a replicated subsystem is not permit-ted. When a new replicated subsystem is created, it is set into this state.

UA-UR unavailable-use as replica denied

Usage as a replicated subsystem is not permitted.

Table 5 States of SCCP subsystems

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is always using a connection-oriented service. You can also see if the subsystem is using a TC. For example, the MAP, INAP, and OMAP are subsystems that use a TC.

The SCCP management subsystem (SCMG = 01) is automatically created when you create an SCCP for a signalling point. The state of the SCMG should normally follow the state of SCCP signalling. Nevertheless, it is possible that remote SCMG subsystems are in state UA-INS while the signalling point is in state AV-EX. This happens when the remote signalling point's MTP has detected that the SCCP is out of service and sends a User Part Unavailable (UPU) message to your signalling point.

g Note that all actions to clear this situation have to be done at the remote signalling point.

SCCP subsystem in state UA-UDIf the state of a subsystem is unavailable the use of replica is denied (UA-UD), it means that the activation of a replicated subsystem is not permitted. When a new replicated subsystem is created, it is set into this state. This state can be changed by giving the NHD command.

Remote SCCP subsystem stateThe states of other remote subsystems should normally be available (AV-EX). State UA-INU (set inactive by user) is set on when the subsystem is created. You can activate the subsystem by using the NHC command. If the state of a subsystem is unavailable, that is deactivated by the system (UA-INS), it means that the state of the signalling point should also be unavailable (for more information, see Section States of SCCP signalling points).

If the state of a remote subsystem is unavailable, that is, it is set inactive by the remote end (UA-INR), it means that a subsystem prohibited message (SSP) has been received or, alternatively, when the user is activating the signalling point, the signalling point does not respond to the subsystem status test message (SST) with a subsystem allowed message (SSA). You cannot change this state to active by the user.

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Error messages of MTP commands

11 Error messages of MTP commandsDuring command execution, errors preventing command execution can occur.

If the data updates included in the command's execution have been partly carried out, a major error has occurred. If there is any other kind of failure in the command's execu-tion, a minor error has occurred.

11.1 MTP command major errorsMajor errors are indicated by the following text:

COMMAND EXECUTION ABORTED

In such cases, the files can contain indefinite data or the contents of the file of the active unit and those of the spare unit can differ from each other.

In addition, one of the error messages below is output.

/*** COMMUNICATION ERROR BETWEEN CCADMI IN CM AND CCADMI IN CCMU ***/

The Common Channel Signalling Management Unit (CCMU) can be overloaded, pre-venting the exchange of messages between the units.

Re-enter the command after the overload is over.

Use the AHO command to see if the system has set alarm 1004. If so, follow the alarm instructions.

One way to circumvent the failure is to perform a controlled switchover for the CCMU.

This failure can also be a result if the CCADMI is missing from the CCMU. Check if the CCADMI process exists and if not, start it by using service terminal commands.

/*** DISK UPDATING FAILED ***/

The disk updating has failed.

Use the AHO command to check if the system has set alarm 1065. If so, follow the alarm instructions.

Use the DUD command to check if the disk updating queue is empty and cancel the change you made with the previous command (for example, remove the created signal-ling link). After that, re-enter the command.

/*** DISTRIBUTION AND DISK UPDATING FAILED ***/

The data distribution and the disk updating have failed. The updating of a signalling file has failed in some units.

Use the AHO command to check the alarms of the main memory, and follow the alarm instructions.

/*** DISTRIBUTION ERROR ***/

The data distribution has failed. The updating of a signalling file has failed in some units.

Use the AHO command to check the alarms of the main memory, and follow the alarm instructions.

/*** INCORRECT MESSAGE ***/

An error is detected within the system's internal information flow. The contents or the length of the message received from the MML program or the CCADMI is incorrect.

The problem can appear due to a faulty software build.

DN98785195 97

Common Channel Signalling (MTP, SCCP and TC) Error messages of MTP commands


/*** L3PARA FILE ERROR ***/

There can be an error in the L3PARA file. Copy the L3PARA file from the OMU's disk to the memory. If there is an error in the file taken from the OMU's disk as well, use the backup copy (if there is one).

11.2 MTP command minor errorsMinor errors are indicated by the following text:

COMMAND EXECUTION FAILED

If a minor error interrupts the command's execution, the files are not modified. In other words, the system is in the same state as it had been before the command was given.

Minor errors can appear due to many different things. The most common reasons are listed below:

• the parameter value given in the command is not permitted or is already in use • the given command is not executed because it prevents or requires some other

function • the system is not able to execute the given command because the state of some

other part of the system is incorrect (for example, a signalling channel is active) • the change to be performed by the command applies to a computer unit which has

not been created or which is not in a state compatible with the execution of the command

Check the parameters given in the command and re-enter the command.

In the case of interrogation commands, only minor errors can occur.

In addition, one of the error messages below is output.

/*** ABATE VALUE MUST BE SMALLER THAN ONSET VALUE ***/

When changing the ABATE value, it must be smaller than the ONSET value. Use the NOI command for the limit values of congestion thresholds.

/*** ACTIVE UNIT STATE INCORRECT ***/

The active unit is in some other working state than WO-EX or the unit type is other than the Central Memory (CM) or the centralised unit of common channel signalling.

/*** ADDITION OF PCM-TSL TO CCS7 CIRCUIT GROUP FAILED ***/

Changing of the signalling link failed because the Routing Administration Library (RTLLIB) failed to connect the signalling time slot to the internal circuit group. Use the RCI command to find out if there are available time slots in the CCS channel.

/*** ALL DESTINATION POINT INDEXES ALREADY USED ***/

All destination point indexes of matrix measurement are already in use. The OID command shows the destination point indexes of matrix measurement.

/*** ALL ORIGINATING POINT INDEXES ALREADY USED ***/

All originating point indexes of matrix measurement are already in use. The OID command shows the originating point indexes of matrix measurement.

/*** ALL SERVICE INDICATOR INDEXES ALREADY USED ***/

All service indicator indexes are already in use. The OIP command shows the service indicator indexes.

/*** ALL SIGNALLING ROUTES CREATED ***/

98 DN98785195




The maximum number of signalling routes have already been created. The NRI command shows the created signalling routes.

/*** ALREADY CONNECTED TO GIVEN UNIT ***/

The signalling link to be transferred is already connected to the unit.

/*** AS7 CIRCUIT GROUP DOES NOT EXIST ***/

There is no route for the PCMs used by the signalling link terminals. The route should be formed when the first signalling link terminal is created. Check the routing by the RCI command.

/*** ATTEMPT TO GIVE MORE THAN ONE ASSOCIATE SIGNALLING ROUTE TO SIGNALLING POINT ***/

Only one of the signalling routes leading to the adjacent signalling point can be associ-ated. For the other routes, the same network should be given as the transfer point, but a different signalling point code than that of the signalling route set.

/*** ATTEMPT TO HAVE RESTRICTED MTP (A INTERFACE) IN SIGNALLING ROUTE SET TOGETHER WITH INDIRECT ROUTES ***/

The signalling route set can be created to support a restricted MTP only if its only sig-nalling route is associated (direct). When trying to support a restricted MTP in a routing set with indirect signalling routes, the task is interrupted and the above execution error message is output.

/*** ATTEMPT TO USE SIGNALLING POINT AS A SIGNALLING TRANSFER POINT ALTHOUGH THIS IS DENIED BY ITS PARAMETER SET ***/

A signalling point cannot be used as a signalling transfer point if this is denied by the parameter set of the signalling point. An execution error message may also be output if the signalling route set which the signalling point is part of has been created to support a restricted MTP and the user attempts to use the signalling point as a signalling transfer point.

/*** CCNETM NOT YET IN ACTIVE STATE ***/

The Signalling Links Management Program Block (CCNETM) could not process the data of the signalling link in the state in question.

/*** CCSU DOES NOT EXIST ***/

The CCSU does not exist.

/*** COMMUNICATION ERROR BETWEEN CCADMI AND CCDESM ***/

Communication between the MTP Data Management Program Block and the Signalling Network Management Program Block failed.

/*** COMMUNICATION ERROR BETWEEN CCADMI AND CCNETM ***/

Communication between the MTP Data Management Program Block and the Signalling Links Management Program Block failed.

/*** COMMUNICATION ERROR BETWEEN CCADMI AND CM3PRO ***/

Communication between the MTP Data Management Program Block and the Routing Working State Administration Program Block failed.

/*** COMMUNICATION ERROR BETWEEN CCADMI AND CS2PRO ***/

Communication between the MTP Data Management Program Block and the Statistical Program Block for MTP (Centralised Part) failed.

/*** COMMUNICATION ERROR BETWEEN CCADMI AND SMNPRO ***/

DN98785195 99



Communication between the MTP Data Management Program Block and the SCCP Management Program Block failed.

/*** COMMUNICATION ERROR BETWEEN CCADMI AND USPMAN ***/

Communication between the MTP Data Management Program Block and the User Part Manager failed.

/*** CONFLICT BETWEEN CDIS66 RECORD COUNT AND L3PARA MAX INDEX VALUES ***/

The maximum index values of matrix measurement are outside CDIS66 record count.

/*** CREATION OF CIRCUIT GROUP CCS7 FAILED ***/

The creation of a signalling link failed because the Routing Administration Library (RTLLIB) failed to create internal circuit group CCS7, to which the signalling route is con-nected.

/*** CS2PRO BUSY WHEN ASKING MAXIMUM VALUES OF STATISTICAL INDEXES ***/

The Statistical Program Block for MTP (Centralised Part) is busy and cannot respond to the interrogation of the maximum values of statistical indexes.

/*** DELETION OF CIRCUIT GROUP CCS7 FAILED ***/

The deletion of the signalling link failed because the Routing Administration Library (RTLLIB) failed to delete circuit group CCS7, to which the signalling route is connected.

/*** DELETION OF PCM-TSL TO CCS7 CIRCUIT GROUP FAILED ***/

The deletion of the signalling link failed because the Routing Administration Library (RTLLIB) failed to delete the signalling time slot to the circuit group.

/*** DESTINATION POINT CODE ALREADY CONNECTED TO MATRIX MEASUREMENT ***/

The signalling destination point code is already connected to the MTP statistics matrix measurement.

/*** DESTINATION POINT CODE DOES NOT CONNECT TO MATRIX MEASUREMENT ***/

The signalling destination point does not connect to the MTP statistics matrix measure-ment.

/*** DIRECT ROUTE FROM ROUTE SET CANNOT BE DELETED BECAUSE THE LINK SET IS USED IN ANOTHER NETWORK ***/

The direct route cannot be deleted if its route set is used in another signalling network.

/*** DISCARDING VALUE MUST BE BIGGER THAN ONSET VALUE ***/

When changing the discarding value, take care of the fact that it is bigger than the onset value. Use the NOI command for the limit values of congestion thresholds.

/*** ERROR IN READING L3PARA FILE ***/

The reading of L3PARA failed.

/*** EXTERNAL CIRCUIT GROUP EXISTS TO SIGNALLING POINT ***/

The User Part Manager (USPMAN) finds an existing external circuit group in the signal-ling point.

/*** EXTERNAL PCM NOT CONNECTED TO EXTERNAL ROUTE ***/

The Routing Administration Library (RTLLIB) failed to connect the external time slot to the external route.

/*** EXTERNAL PCM-TSL ALREADY USED FOR SIGNALLING LINK ***/

The external time slot is already in use./*** EXTERNAL PCM-TSL IS CONNECTED TO OTHER ROUTE THAN CCS7 ***/

100 DN98785195




The Routing Administration Library (RTLLIB) does not connect the external time slot to the external route when it detects that the time slot is connected to a route other than CCS7. Choose another external time slot or delete the time slot from the route using it, and connect it to the CCS7 route.

/*** EXTERNAL ROUTING FAILURE ***/

The external routing by the Routing Administration Library (RTLLIB) failed.

/*** EXCHANGE TERMINAL INACTIVE ***/

The exchange terminal is in other than active working state in the Signalling Link Control File (SLCONT).

/*** FAILED TO CLARIFY UPPER LIMIT OF PCM NUMBER ***/

A failure in the clarification of the upper limit of the number of the PCMs.

/*** FILE ACCESS ERROR ***/

The File System Library (FISLIB) has sent a file access error message to the MTP Data Management Program Block (CCADMI). CCADMI has not been able either to read or write the file, depending on which task the error has occurred in. For further information on the error, see the log records saved in the central memory by CCADMI.

/*** ILLEGAL MESSAGE LENGTH BETWEEN MML AND CCADMI ***/

The length of the message between the MML and the CCADMI is illegal.

/*** ILLEGAL PARAMETER ***/

One of the parameters given by the user is illegal.

/*** ILLEGAL PCM ***/

An illegal PCM.

/*** INCORRECT LINK STATE ***/

The signalling link is in a state where the modification command is impossible.

/*** INCORRECT MESSAGE FROM CCADMI ***/

The MML received an incorrect message from the CCADMI.

/*** INCORRECT PARAMETER SET NAME ***/

The parameter set name is incorrect.

/*** INCORRECT SERVICE NAME ***/

The service name is incorrect.

/*** INCORRECT SIGNALLING LINK SET NAME ***/

The signalling link set name is incorrect.

/*** INCORRECT SIGNALLING LINK TABLE IN CCXHAN ***/

The signalling link table used by the Signalling Link Data Handling MML is incorrect. The signalling link table contains the signalling point codes given by the user.

/*** INCORRECT SIGNALLING POINT NAME ***/

The signalling point name is incorrect.

/*** INCORRECT SIGNALLING TRANSFER POINT NAME ***/

The signalling transfer point name is incorrect.

/*** INSUFFICIENT NUMBER OF PARAMETERS ***/

The user has not given the data of the signalling link to be modified.

DN98785195 101



/*** INTERNAL PCM NOT CONNECTED TO AS7 CIRCUIT GROUP ***/

The PCM used by the signalling link terminal has not been connected to the AS7 circuit group. Check the routing by the RCI command. The time slots used by the signalling link terminal should be connected to the AS7 circuit group when creating the terminal. Check the data of the signalling link terminal by the commands of the equipment database.

/*** GIVEN PARAMETER VALUE MUST BE BIGGER THAN VALUE OF THE LOWER LEVEL ***/

When modifying the limit values of congestion thresholds, it must be taken care of that the limit values increase as the threshold value increases. Use the NOI command for limit values of congestion thresholds.

/*** LAST SIGNALLING LINK IN SIGNALLING LINK SET ***/

Deleting the signalling link fails if the signalling link is the last one in the signalling link set. In such a case, the signalling link set must first be deleted by the NSD command.

/*** MEASUREMENT 6.6 NOT STOPPED ***/

MTP measurements must be stopped when modifying MTP statistics indexes. Measure-ment 6.6 has not been stopped. The measurement is in accord with the ITU-T Recom-mendation Q.752. The measurements can be stopped by the OSD command.

/*** NEITHER SIGNALLING TERMINAL NOR SIGNALLING LINK SET INITIALIZED ***/

The signalling link terminal has not been initialised, and the signalling link has not been connected to any signalling link set.

/*** NO ASSOCIATE SIGNALLING ROUTE IN SIGNALLING ROUTE SET TO SIGNALLING TRANSFER POINT ***/

The signalling point cannot be used as the signalling transfer point because there is no associate signalling route to it.

/*** NO EXCHANGE TERMINAL FOR SIGNALLING DATA LINK ***/

There is no exchange terminal for the external PCM.

/*** NO FREE TERMINAL FUNCTION ***/

The user is trying to create more signalling links than allowed.

/*** NO FREE TERMINAL IN UNIT ***/

The transfer of the signalling link to another unit fails because there is no free terminal in the unit. A new signalling link terminal must be equipped in the unit.

/*** ONLY ONE SIGNALLING ROUTE IN SIGNALLING ROUTE SET ***/

The last route in the signalling route set cannot be deleted with the NRR command, but the whole signalling route set must be deleted with the NRD command.

/*** ORIGINATING POINT CODE ALREADY CONNECTED TO MATRIX MEASUREMENT ***/

The originating point is already connected to the MTP matrix measurement Q.752 6.6.

/*** ORIGINATING POINT CODE DOES NOT CONNECT TO MATRIX MEASUREMENT ***/

The originating point is not connected to the MTP matrix measurement Q.752 6.6.

/*** OTHER SIGNALLING POINTS EXIST IN SIGNALLING NETWORK ***/

The deletion of the signalling point is not allowed if there are other signalling points in the signalling network.

/*** OWN ADDITIONAL SIGNALLING POINT EXISTS ***/

There is another signalling point code for the signalling point in the signalling network. The data of the other signalling point code is defined in L3PARA (CCITT7 Level 3

102 DN98785195




Parameter File). Check the data with the NMI command and delete the other signalling point code unless it is necessary.

/*** OPC/DPC BUFFER OVERFLOW ***/

An overflow in the buffer which the Signalling Route Set Data Handling MML uses for transferring the Originating Point Codes (OPC) or Destination Point Codes (DPC) in the CCADMI message.

/*** OWN SIGNALLING POINT ***/

The function cannot be performed for the own signalling point.

/*** OWN SIGNALLING POINT DOES NOT EXIST ***/

The function cannot be performed until an own signalling point has been created. The signalling point can be created by the NRP command.

/*** OWN SIGNALLING POINT IS END POINT ***/

The user has attempted to define functions that are impossible for the signalling point which is the end point.

/*** PARAMETER SET ALREADY EXISTS ***/

The parameter set exists already.

/*** PARAMETER SET DOES NOT EXIST ***/

The parameter set does not exist.

/*** PARAMETER SET IN USE ***/

You are trying to delete or modify a parameter set which is in use. Check the parameter sets used by the signalling data links with the NCI command or those used by the sig-nalling route sets with the NRI command.

/*** PARAMETER SET NAME ALREADY RESERVED ***/

The parameter set name has already been reserved.

/*** PASSIVE UNIT STATE INCORRECT ***/

The passive unit is in SP-RE state. Wait until the passive unit is in SP-EX state.

/*** PCM CIRCUITS EXIST TO SIGNALLING POINT ***/

The deletion of the signalling route set is impossible because PCM circuits have been connected to the signalling point.

/*** PREPARING FOR SWITCHOVER ***/

The switchover is being prepared. The MML commands are not received.

/*** REMOTE ACKNOWLEDGEMENT MISSED ***/

The remote acknowledgement has been missed.

/*** REQUESTED STATE ALREADY EXISTS ***/

The requested state already exists.

/*** RSPARA FILE ACCESSING ERROR ***/

An attempt to access files outside Signalling Route Set Parameter File (RSPARA).

/*** SEMIPERMANENT FILE UPDATING BUSY ***/

The semipermanent file updating is in progress. A new task requiring semipermanent file updating is not received simultaneously. Give a new command.

/*** SERVICE ALREADY EXISTS ***/

DN98785195 103



The service which the user tried to create already exists.

/*** SERVICE NAME ALREADY EXISTS ***/

The service name is already used by another user part.

/*** SIGNALLING LINK ACTIVATION DENIED ***/

The signalling link activation is denied. Use the NLA command to enable the activation.

/*** SIGNALLING LINK ACTIVATION FAILED ***/

The signalling link activation failed. This can be caused by a fault in the data link con-nection or the remote end. If the signalling link activation fails, alarm 2072 is given.

/*** SIGNALLING LINK ACTIVATION NOT DENIED ***/

The signalling link activation is not denied. Deny the activation with the NLD command.

/*** SIGNALLING LINK ALREADY EXISTS ***/

The signalling link already exists.

/*** SIGNALLING LINK BLOCKING FAILED ***/

The signalling link blocking failed. The connection to the signalling link terminal can be faulty. Check the alarms.

/*** SIGNALLING LINK DEBLOCKING FAILED ***/

The signalling link deblocking failed. The connection to the signalling link terminal can be faulty. Check the alarms.

/*** SIGNALLING LINK DOES NOT EXIST ***/

The signalling link does not exist.

/*** SIGNALLING LINK INACTIVATION FAILED ***/

The signalling link deactivation failed. The connection to the signalling link terminal can be faulty. Check the alarms.

/*** SIGNALLING LINK INHIBITING FAILED ***/

The signalling link inhibiting failed.

/*** SIGNALLING LINK INHIBITING LOCALLY DENIED ***/

The signalling link inhibiting is locally denied. The inhibiting would make one of the sig-nalling points be out of reach. Therefore, signalling link inhibiting is denied.

/*** SIGNALLING LINK INHIBITING REMOTELY DENIED ***/

The remote end denied the signalling link inhibiting. The inhibiting would make one of the signalling points be out of reach of the remote end. Therefore, the remote end denies signalling link inhibiting.

/*** SIGNALLING LINK IS CONNECTED TO SIGNALLING LINK SET ***/

The deletion of the signalling link is denied because the signalling link is connected to the signalling link set./*** SIGNALLING LINK IS NOT CONNECTED TO SIGNALLING LINK SET ***/

The modification of the signalling link state is denied because the signalling link is not connected to the signalling link set.

/*** SIGNALLING LINK NOT ACTIVATED ***/

The signalling link activation failed.

/*** SIGNALLING LINK NOT INACTIVATED BY USER ***/

104 DN98785195




To deny the signalling link activation, the signalling link must be in UA-INU state. Use the NCL command to set the UA-INU state.

/*** SIGNALLING LINK NOT IN SIGNALLING LINK SET ***/

The signalling link has not been connected to the signalling link set.

/*** SIGNALLING LINK SET ALREADY EXISTS ***/

The signalling link set already exists.

/*** SIGNALLING LINK SET DOES NOT EXIST ***/

The signalling link set does not exist.

/*** SIGNALLING LINK SET FILE FULL ***/

The signalling link set file is full. The creation of a signalling link set is denied. The exchange needs a new file set.

/*** SIGNALLING LINK SET IS CONNECTED TO SIGNALLING ROUTE SET ***/

The deletion of the signalling link set is denied because the signalling link set is con-nected to the signalling route set.

/*** SIGNALLING LINK SET IS NOT CONNECTED TO SIGNALLING ROUTE SET ***/

Modifying the signalling link state is denied because the signalling link set is not con-nected to the signalling route set.

/*** SIGNALLING LINK SET NAME ALREADY RESERVED ***/

The signalling link set name is already reserved.

/*** SIGNALLING LINK STARTING FAILED ***/

Starting the signalling link failed. The data link connection or the remote end can be faulty.

/*** SIGNALLING LINK STATE CHANGE BUSY ***/

The signalling link state is being changed.

/*** SIGNALLING LINK UNINHIBITING FAILED ***/

The signalling link uninhibiting failed.

/*** SIGNALLING LINK UNINHIBITING IMPOSSIBLE ***/

The signalling link uninhibiting is impossible because there is no connection to the remote end.

/*** SIGNALLING NETWORK DOES NOT EXIST ***/

The signalling network does not exist.

/*** SIGNALLING POINT ALREADY BELONGS TO PERIODIC MRVT ***/

The signalling point already belongs to the MTP routing verification test.

/*** SIGNALLING POINT ALREADY EXISTS ***/

The signalling point already exists.

/*** SIGNALLING POINT CODE ALREADY EXISTS ***/

The signalling point code already exists.

/*** SIGNALLING POINT DOES NOT BELONG TO PERIODIC MRVT ***/

The signalling point does not belong to the MTP routing verification test.

/*** SIGNALLING POINT DOES NOT EXIST ***/

DN98785195 105



The signalling point does not exist.

/*** SIGNALLING POINT IS USED BY SCCP ***/

The signalling point which the user is trying to delete is used by the Signalling Control Connection Part (SCCP).

/*** SIGNALLING POINT NAME ALREADY RESERVED ***/

The signalling point name is already reserved.

/*** SIGNALLING ROUTE ACTIVATION DENIED ***/

The signalling route activation is denied. Use the NVA command to enable the route acti-vation.

/*** SIGNALLING ROUTE ACTIVATION FAILED ***/

The signalling route activation failed. Check with the NSI command if the signalling route set of the route is in AV state.

/*** SIGNALLING ROUTE ACTIVATION NOT DENIED ***/

The signalling route activation is not denied. Set the route in UA-AD state with the NVD command.

/*** SIGNALLING ROUTE ALREADY EXISTS ***/

The signalling route already exists in the signalling route set. Check with the NRI command.

/*** SIGNALLING ROUTE DOES NOT EXIST ***/

The signalling route does not exist in the signalling route set.

/*** SIGNALLING ROUTE INACTIVATION FAILED ***/

The signalling route inactivation failed.

/*** SIGNALLING ROUTE SET ALREADY EXISTS ***/

The signalling route set already exists. Check with the NRI command.

/*** SIGNALLING ROUTE SET DOES NOT EXIST ***/

The signalling route set does not exist. Check with the NRI command.

/*** SIGNALLING ROUTE SET FILE FULL ***/

The Signalling Route Set File (ROSETF) is full, that is, the maximum number of signal-ling route sets have been created in the exchange. The exchange needs a new file set.

/*** SIGNALLING ROUTE SET STATE NOT AVAILABLE ***/

The signalling route set state is not available. Therefore, the load sharing of the signal-ling route links is denied. Check the signalling route set state with the NRI command.

/*** SIGNALLING ROUTE STATE CHANGE BUSY ***/

The signalling route state is being changed in the central memory.

/*** SIGNALLING ROUTE STATE IS NOT UA-INU ***/

The signalling route is not in UA-INU state. Change the state with the NVC command.

/*** SIGNALLING ROUTE TO ADJACENT SP ALREADY EXISTS ***/

There is already a direct signalling route to the adjacent signalling point. Check with the NRI command.

/*** SIGNALLING ROUTES AND ROUTE SET STATES INQUIRY FROM CCM BUSY ***/

The signalling routes and route set states are being inquired from the CCM.

106 DN98785195




/*** SIGNALLING TERMINAL NOT INITIALIZED ***/

The signalling terminal has not been initialised. There is a lack of terminals.

/*** SIGNALLING TERMINAL UNIT DOES NOT EXIST ***/

The signalling terminal unit (CCSU, BCSU, or an equivalent of these) does not exist.

/*** SIGNALLING TRANSFER POINT DOES NOT EXIST ***/

The signalling transfer point does not exist or no signalling link set has been created for it. Check the signalling point and the signalling link set with the NSI command.

/*** SIGNALLING TRANSFER POINT POLICING DEFINED TO SIGNALLING POINT ***/

An STP policing has been defined for the signalling transfer point.

/*** SIGNALLING UNIT SWITCHOVER IS REQUIRED AND LINK NOT IN LINK SET ***/

Signalling unit switchover is required and the signalling link must be connected to the signalling link set before the signalling link can be activated.

/*** SIGNALLING UNIT SWITCHOVER IS REQUIRED BEFORE LINK CAN BE ACTIVATED ***/

Initialise the signalling terminal unit by a signalling unit switchover or restart the unit.

/*** SIO ALREADY CONNECTED TO MATRIX MEASUREMENT ***/

The service information octet is already connected to the MTP statistics matrix measure-ment.

/*** SIO DOES NOT CONNECT TO MATRIX MEASUREMENT ***/

The service information octet is not connected to the MTP statistics matrix measure-ment.

/*** SLC RESERVED FOR OTHER SIGNALLING LINK ***/

The signalling link code has been reserved for another signalling link in the signalling link set. Check with the NSI command.

/*** SLINKF FILE ACCESSING ERROR ***/

An attempt to access files outside the Signalling Link File (SLINKF).

/*** SLNPAR FILE ACCESSING ERROR ***/

An attempt to access files outside the Signalling Link Parameter File (SLNPAR).

/*** SLN PARAMETER SET ALREADY EXISTS ***/

The user is trying to create an SLN parameter set which already exists. The NOI command shows the existing parameter sets.

/*** SLN PARAMETER SET DOES NOT EXIST ***/

The SLN parameter set does not exist. Check the identifiers of the parameter set. The NOI command shows the existing SLN parameter sets.

/*** SLN PARAMETER SET IS IN USE ***/

The SLN parameter set is in use. The NCI command shows the links using the param-eter set.

/*** SOURCE PARAMETER SET DOES NOT EXIST ***/

The source parameter set does not exist. Check the identifiers of the parameter set.

/*** SOURCE PARAMETER SET IS NOT USED ***/

The source parameter set is not used by any signalling point.

DN98785195 107



/*** SOURCE SLN SET DOES NOT EXIST ***/

The source SLN parameter set does not exist. Check the identifiers of the parameter set with the NOI command.

/*** SP IS USED AS OWN ADDITIONAL SP ***/

The signalling point is used as an own additional signalling point which is saved in the CCITT7 Level 3 Parameter File (L3PARA). Check with the NMI command.

/*** SP IS USED AS SIGNALLING TRANSFER POINT IN OTHER SIGNALLING ROUTE SET ***/

The signalling point TO which the direct signalling route to be deleted is connected is used as a signalling transfer point in another signalling route set.

/*** STATE CHANGE IS IMPOSSIBLE ***/

The state change is impossible. Check the route state with the NVI command.

/*** THE HANDLING OF THE LINK IN THE JAPANESE NETWORK IS DENIED ***/

It is not possible to block the signalling link in the Japanese SS7 network (specification of NTT and TTC).

/*** TIME LIMIT EXCEEDED ***/

The message set by CCADMI was not answered before the timeout.

/*** UNKNOWN SERVICE ***/

The service indicator is unknown.

108 DN98785195


Id:0900d805807e343aConfidential

SS7 signalling network parameters

12 SS7 signalling network parametersWith the signalling parameters it is possible to control and modify certain functions of the signalling network. The signalling parameters are divided into six different levels, depending on which part of the signalling system they affect.

MTP level parameters

• MTP level 3 parameters • CCS7 signalling network-specific parameters • signalling link-specific parameters • signalling route set-specific parameters

SCCP and TC level parameters

• SCCP signalling point parameters • SCCP subsystem parameters

For some levels, it is possible to define the number of special parameter sets. The parameter sets can be connected so that different parts of the signalling system use dif-ferent parameter sets. This way it is possible to use different kinds of signalling in differ-ent directions.

For example, there can be two different signalling link parameter sets defined, one of which is connected to the signalling links leading to network element X, and the other one is connected to the signalling links leading to network element Y. In this case, the signalling functions are different towards network element X, than the ones towards network element Y.

There are few parameter sets predefined for a different kind of SS7 signalling standards (for example, ITU-T, ANSI, JAPAN). It is recommended to use these parameter sets or at least to start with them. If there is a need to change them, it is reasonable to create a new one on the basis of the predefined one.

Table Parameter files and their contents lists the signalling levels and the predefined parameter sets within the level. There can also be some country-specific parameter sets predefined or some of the sets listed below can be left out depending on the used software release.

Parameter level Effected parts MML commands

MTP level 3 parameters Message Transfer Part (MTP) of the network element

NMI, NMM

signalling network parameters signalling network (NA0, NA1, IN0, or IN1), that is, all four signalling networks have own network param-eters

NMO, NMC

signalling link parameters signalling links NO command group

signalling route set parameters signalling route set NN command group

SCCP signalling point parame-ters

SCCP signalling point NFL, NFN

SCCP subsystem parameters SCCP subsystems NFM, NFO

Table 6 Parameter levels, affected parts and the MML commands to handle them

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Common Channel Signalling (MTP, SCCP and TC) SS7 signalling network parameters


Signalling level Predefined parameter sets

MTP level 3 parameters All parameters have a default value.

Signalling network parameters These parameters can be defined separately for each signalling network (IN0, IN1, NA0, and NA1). All parameters have a default value.

Signalling link parameters The following parameter sets are predefined:

• ITU-T for signalling parameters defined by International Telecom-munications Union (ITU) in Q.703–Q.704.

• BTNR 146 for signalling parameters defined by British Telecom-munications Network Requirement (BTNR).

• ANSI T111 for signalling parameters defined by American National Standards Institute (ANSI) in T1.111 and T1.114.

• JAPAN TTC for signalling parameters defined by Telecommunica-tion Technology Committee (TTC) in JT.Q703 and JT.Q704.

• JAPAN NTT for signalling parameters defined by Nippon Tele-graph and Telecommunication Corporation (NTT) in JT.Q703 and JT.Q704.

• ITU-T 2.0M for large capacity signalling links defined by Interna-tional Telecommunications Union (ITU).

• TU-T 1.5M for large capacity signalling links defined by Interna-tional Telecommunications Union (ITU).

• IETF M3UA for IP type signalling links defined by Internet Engi-neering Task Force (IETF).

Signalling route set parame-ters

The following parameter sets are predefined:

• ITU-T for signalling parameters defined by International Telecom-munications Union (ITU) in Q.703 and Q.704.

• A INTERFACE for A interface, for example, between MSC and BSC or ATM Module and MSC.

• BTNR 146 for signalling parameters defined by British Telecom-munications Network Requirement (BTNR).

• ANSI T111 for signalling parameters defined by American National Standards Institute (ANSI) in T1.111 and T1.114.

• JAPAN TTC for signalling parameters defined by Telecommunica-tion Technology Committee (TTC) in JT.Q703 and JT.Q704.

• JAPAN NTT for signalling parameters defined by Nippon Tele-graph and Telecommunication Corporation (NTT) in JT.Q703 and JT.Q704.

• IETF M3UA for routes using IP type signalling links defined by Internet Engineering Task Force (IETF).

SCCP signalling point param-eters

The following parameter sets are predefined:

• BLUE for signalling parameters defined by International Telecom-munications Union (ITU) in Q.700 - Q.716, Blue Book.

• A-INT for A interface e.g. between MSC and BSC or ATM Module and MSC.

• WHITE for signalling parameters defined by International Tele-communications Union (ITU) in Q.700 - Q.716 3/93, White Book.

Table 7 Signalling levels and their predefined parameter sets

110 DN98785195




Since several signalling route sets and signalling links use identical parameter combi-nations, the parameter files RSPARA and SLNPAR contain these combinations, which we call parameter sets, so you only need to store information on which parameter sets the signalling route sets or links use with the actual route set files or signalling link files. This means that if you modify the contents of a signalling link parameter set, for example, the functions of the MTP change in the same way for all the links that use the modified parameter set.

12.1 MTP level 3 parametersLevel 3 parameters define the functions of the whole MTP. Some of the parameter values are related to monitoring the functions, while others define various limits.

The parameters are divided into six groups (A-F):

A SS7 general parameters

B Parameters for managing overload

C Timing parameters of own signalling point

D Parameters for testing

E SIO parameters

F Parameters for SS7 statistics

The following table lists the parameter groups, parameters and their indexes, parameter names and their meanings, the possible values of each parameter, and the value range, as well as the recommended value if that exists.

SCCP subsystem parameters The following parameter sets are predefined:

• GENER for general use in other than with A interface. • A-INT for A interface, for example, between MSC and BSC or ATM

Module and MSC.

Signalling level Predefined parameter sets

Table 7 Signalling levels and their predefined parameter sets (Cont.)

The name of the parameter file Content

L3PARA level 3 parameters

RSPARA signalling route set parameters

SLNPAR signalling link parameters

SNWPAR signalling network parameters

Table 8 Parameter files and their contents

DN98785195 111



Parameter group Parameter name Value range (quality of value)

Parameter group and number

Parameter explanation Recommended value

A SS7 COMMON PARAMETERS

A0-A9 DISTRIB_MTP_UNIT_TYPE_0 - 9

Defines those unit types on an exchange where you can create signalling links.

Usually, parameter values need not be changed in the MSC, HLR, BSC, or fixed network exchanges because the unit types CCSU, BCSU, and BSU have been prebuilt. In the PMR, the units CM and CCC have been prebuilt.

B OVERLOAD CONTROL PARAMETERS

B0 MAX_NB_OF_NOTICES 10 to 30

The largest amount of incoming messages are allowed to enter a centralised unit during a message monitoring period (100 ms). The purpose of the parameter is to control overload within the exchange. The parameter value should not be changed.

C TIMER PARAMETERS FOR OWN SIGNALLING POINT

C0 LINK_TEST_PERIOD 1500 to 45000 (10 ms)

The sending period for signalling link test messages. The period applies to a group of ten signalling links. This means that when an exchange has 30 links, the test message goes to each link in every third sending period.

4000 (40 sec.)

C1 Q704_T18_LINK_AVAIL_WAIT 1000 to 6000 (10 ms)

The time used to control the availability of the links when a signalling transfer point is restarted. The value depends on the implementation and on the network.

2000

C2 Q704_T19_TRA_WAIT 200 to 1000 (10 ms)

The timer controlling the reception of all TRA messages while the signalling transfer point is being restarted when the restarting is made as defined in the CCITT Blue Book. The timer is defined by the P7 parameter when the system follows the White Book.

400

C3 Q704_T20_TRAF_RESTARTING_TIME 200 to 1000 (10 ms)

The timer controlling the sending of all TRA messages when the signalling transfer point is being restarted.

400

C4 T111_T26 1000 to 2000 (10 ms)

Defines the timer for the resending of TRW messages when the signalling transfer point is being restarted. The timer is defined in the ANSI standards.

1500

Table 9 MTP level 3 parameters

112 DN98785195




C5 Q714_T_GUARD 600 to 15000 (100 ms)

Defines the monitoring time used for the signalling connections when the signalling transfer point is being restarted.

6000

C6 T111_T27 300 to 500 (10 ms)

After commencing the restart procedure of a signal-ling point, all the signalling links of the exchange keep sending the processor outage state indicator to the partner exchanges for a given time (defined in this parameter), in order to make sure that all adjacent sig-nalling points recognise that this point cannot be reached any more.

C7 TETRA_LINK_FAILURE_DELAY 0 to 200 (100ms)

Delay timer, waiting for informing TETRA application about signalling link failure.

D PARAMETERS FOR TESTING

D0 L2_TEST_MSG_SIO 0 to FF

The service information octet used by the CCS System Test Message Generator (MSGGEN) reads the data only when it starts up. After changing the parameter values, the MSGGEN has to be restarted before new values can be included in the contents of the test messages.

8F (NA0 network user part F)

D1 TEST_MSG_LENGTH 0 to 272

The length of the SIF part in the MSGGEN messages of the CCS System Test Message Generator. This parameter affects only those messages whose length can be modified. The value for this parameter can be changed while the MSGGEN is running, and the MSGGEN does not need to be restarted.

smaller than 272

E INTERNAL ROUTING PARAMETERS

E0 INT_ST7_ROUTE

Defines the number of the internal route which includes the PCM time slots used by the signalling link terminals between the unit and the switching network.

E1 EXT_ST7_ROUTE

Defines the number of the external route which includes the external PCM time slots used by the sig-nalling link terminals.

E2 INT_ST7_ROUTE_NAME

Defines the name of the internal route which includes the PCM time slots used by the signalling link termi-nals between the unit and the switching network.




Table 9 MTP level 3 parameters (Cont.)

DN98785195 113



E3 EXT_ST7_ROUTE_NAME

Defines the name of the external route which includes the external PCM time slots used by the signalling link terminals.

E4 INTERNAL_ROUTING_FOR_SL

Defines whether the system tries to update the signal-ling link-related PCM/TSL data in the routing data of the CM3PRO. Used only on test exchanges that have no group switch (GSW).

F SS7 STATISTICS PARAMETERS

F0 SUCC_UNIT_COLL_COUNT_5 2 to 10

Defines the amount of MTP decentralised units from which the statistics counters are collected at a time during a 5–minute monitoring period.

4

F1 SUCC_UNIT_COLL_COUNT_30 2 to 20

Defines the amount of MTP decentralised units from which the statistics counters are collected one-by-one during a 30 minute monitoring period.

10

F2 SL_LOG_TYPE NORMAL,CYCLIC

Type of the signalling link event log can be either NORMAL or CYCLIC. The buffer can be emptied with the OLE command.

CYCLIC

F3 SP_LOG_TYPE NORMAL,CYCLIC

Type of the signalling point event log can be either NORMAL or CYCLIC. The buffer can be emptied with the ONE command.

CYCLIC

F4 SL_LOG_MAX_COUNT 16 to 32

The maximum amount of changes in the state of a sig-nalling link that can be stored in the buffer.

F5 SP_LOG_MAX_COUNT 16 to 32

The maximum amount of changes in the state of a sig-nalling point that can be stored in the buffer.

F6 USER_NOTICE_ACT ACTIVE, PASSIVE

Controls the notices that statistics output for the user.

F7 SCCP_LOG_TYPE NORMAL, CYCLIC

Type of the SCCP event log buffer. The buffer can be emptied with the OTE command.

F8 TC_LOG_TYPE NORMAL, CYCLIC

Type of the TC event log buffer. The buffer can be emptied with the OTE command.




Table 9 MTP level 3 parameters (Cont.)

114 DN98785195




12.2 SS7 signalling network parametersThese parameters apply to the whole signalling network.

The parameters are divided into four groups (J-M):

J Network-specific parameters

K Parameters for controlling international congestion

L Parameters controlling national congestion

M SLS parameters

Table CCS7 signalling network-specific parameters lists the parameter groups, param-eters and their indexes, parameter names and their meanings, all possible values, the quality of parameter value, and the recommended value, if any.




J NETWORK SPECIFIC PARAMETERS

J0 CONGESTION_METHOD NO, INT, NAT, and NATP

There are three congestion methods:

• International method (INT): the congestion criteria is the filling degree (1 limit) of the sending buffer, whose limit values are defined in the Signalling Link Parameter File (SLNPAR). The congestion level directly follows the occupancy of the buffer. T29 and T30 timers are used to control traffic restriction according to the definitions made with the K0 to K5 parameters .

• National method without prioritisation of signalling messages (NAT): the congestion criteria is the filling degree (1 limit) of the sending buffer, the limit values of which are defined in the Signalling Link Parameter File (SLNPAR). The congestion level is determined by Tx and Ty timers. The congestion level can have 1 to 3 values, and the traffic is restricted as required by the prevailing congestion level and as defined in the L1 to L3 parameters.

• National method with prioritization of messages (NATP): the congestion criteria is the occupancy (3 limits) of the sending buffer, the limit values of which are defined in the Signalling Link Parameter File (SLNPAR). The congestion level determines how the messages are handled (for example, on congestion level 3, only messages with priority 3 or higher are routed forwards).

K INTERNATIONAL CONGESTION CONTROL METHOD PARAMETERS

K0 NB_OF_UP_LEVELS 1 to 5

The number of restriction levels for the originating traffic concerning the international congestion method.

Table 10 CCS7 signalling network-specific parameters

DN98785195 115



K1 RESTRICT_PR_OF_UP_L1 0 to 40 (%)

The restriction percentage for the originating traffic on restriction level 1. The T29 and T30 timers determine the restriction level. The default value is 40%.









K6 Q764_T29 30 to 60 (0.01s)

When the first congestion indication is received by the ISDN User Part, the traffic load in the affected destina-tion point code is reduced by one step. At the same time, two timers – T29 and T30 – are started. During T29, all the received congestion indications for the same destination point code are ignored not to reduce traffic too rapidly. Reception of a congestion indication after the expiry of T29, but still during T30, decreases the traffic load by one more step and restarts T29 and T30. This step-by-step reduction of the ISDN User Part signalling traffic is continued until a maximum reduction is obtained by arriving at the last step. If T30 expires (that is, no congestion indications are no longer received during the T30 period), the traffic is increased step-by-step and T30 is restarted unless the full traffic load has been resumed.

50

K7 Q764_T30 500 to 1000 (0.01s)

See K6. 600

L NATIONAL CONGESTION CONTROL METHOD PARAMETERS

L0 PREDETERMINED_CONG_LEVEL 1 to 3




Table 10 CCS7 signalling network-specific parameters (Cont.)

116 DN98785195




Defines the default value for the congestion level that is reached when the buffer occupancy limit is exceeded for the first time, or when the congestion level is coded as 0 in a received TFC message.

L1 RESTRICT_PR_OF_MTP_L1 0 to 50 (%)

The restriction percentage for originating traffic on con-gestion level 1.





L4 Q704_TX 5 to 200 (0.01s)

The timer raising the congestion level when the filling limit of the transmit buffer has been exceeded. The smaller the parameter value is, the quicker the conges-tion level is raised. If the signalling link congestion status is set to 's' and the buffer occupancy continues to be above the set congestion threshold during Tx, the signalling link congestion status is updated with the new value s + 1.

200

L5 Q704_TY 5 to 200 (0.01s)

The timer that lowered the congestion level when con-gestion was on, but then the filling degree of the sending buffer decreased and went below the set limit. The smaller the value of Ty is, the quicker the conges-tion level decreases. If the signalling link congestion status is set to s and the buffer occupancy continues to be below the abatement threshold during Ty, the signal-ling link congestion status is updated with the new value s - 1.

M SLS BITS

M0 LINK_SLS_BIT_MASK 11111111

Defines the SLS bit mask for link selection in message routing.

M1 ROUTE_SLS_BIT_MASK 11111111

Defines the SLS bit mask for route selection in message routing.

M2 SLS_LENGTH 4

Defines the bit length of SLS code in the signalling network for link selection.





DN98785195 117



12.3 Signalling link parametersThe parameters in the signalling link-specific parameter set define how the signalling links function.

You can interrogate the values of the parameters of an existing signalling link parameter set with the NOI command.

The parameters are divided into seven groups (A-G):

A Miscellaneous parameters on MTP level 2

B Control parameters for the error ratio on MTP level 2 (as defined by the ITU)

C Timer parameters for MTP level 2 (as defined by ITU)

D Miscellaneous parameters on MTP level 3

E Signalling congestion control parameters

F Timer parameters for MTP level 3

G ATM-specific parameters (SAAL level)

Table Signalling link parameters lists the parameter groups, parameters and their indexes, parameter names and their meanings, all possible values, the quality of the value, and the recommended value, if any.

M3 INTERNAL_SLS_LENGTH 5

Defines the bit length of SLS code used internally in message routing.

M4 NEW_SLS_IN_SCCP0- CLASS NOT IN USE

Indicates whether MTP reselects an SLS code for STP messages whose in-sequence delivery is not manda-tory.

M5 LS_LICENCE_KEY_1 0

Specifies licence key 1 for advanced load sharing pro-cedures.

M6 LS_LICENCE_KEY_2 0

Specifies licence key 2 for advanced load sharing pro-cedures.





118 DN98785195




Parameter group

Parameter name Value range (quality of value)



A MISCELLANEOUS MTP LEVEL 2 PARAMETERS

A0 LI_CODING STANDARD, BTNR

Controlling the LI coding.

BTNR is a specific method in BTNR Spec. (UK).

STANDARD

A1 BIT_D_CODING_IN_LSSU STANDARD, BTNR

Controlling the D bit coding in the LSSUs.

BTNR is a specific method in BTNR Spec. (UK).

STANDARD

A2 BIT_D_CHECK_IN_LSSU YES, NO

Controlling the D bit checking in the received LSSUs (1H Bit D checked from the received LSSU).

NO

A3 L2_ERROR_CORRECTION BASIC, PCR

Controlling error rate monitoring in the transmission direc-tion. PCR is for preventive cyclic retransmission for satel-lite links. (See the parameters B7, PCR_N1 and B8, PCR_N2.)

BASIC

A4 SN_RANGE 40 to 4095

Maximum value for backward sequence number and forward sequence number of signalling unit.

A5 JT_Q703_K 40 to 127

Defines the number of transmitted MSU messages without positive acknowledgement.

This parameter is relevant only in the Japanese signalling network.

JAPAN: 40

B MTP LEVEL 2 ERROR RATE MONITORING PARAME-TERS

B0 SUERM_T 8 to 512

Controlling the error rate of the message units SUERM_T, SUERM_D, and SUERM_N (see CCITT Q703 10.2).

ITU: 64

ANSI: 64

JAPAN: 285

B1 SUERM_D 16 to 1024


ITU: 256

ANSI: 256

JAPAN: 16

B2 SUERM_N 8 to 24


16

B3 AERM_TIN 1 to 16

Table 11 Signalling link parameters

DN98785195 119



Controlling the error rate of the alignment AERM_TIN (see CCITT Q703 10.3).

4

B4 AERM_TIE 1 to 8

Controlling the error rate of the alignment AERM_TIE (see CCITT Q703 10.3).

1

B5 AERM_M 1 to 16

Controlling the error rate of the alignment AERM_M (see CCITT Q703 10.3).

5

B6 AERM_N 8 to 24

Controlling the error rate of the alignment AERM_N (see CCITT Q703 10.3).

16

B7 PCR_N1 (preventive cyclic retransmission) 1 to 127

PCR_N1, number of MSUs that can be resent. The parameter is valid only if the A3 parameter, L2_ERROR_CORRECTION has the value PCR.

The parameter is normally used with satellite signalling links. Both link ends must support this method.

For more information, see ITU-T Recommendation Q.703 (07/96) - Signalling link (chapter 6).

127

B8 PCR_N2 300 to 6000

PCR_N2, number of MSUs that can be resent. The parameter is valid only if the A3 parameter, L2_ERROR_CORRECTION has the PCR value.

The parameter is normally used with satellite signalling links. Both link ends must support this method.

For more information, see ITU-T Recommendation Q.703 (07/96) - Signalling link (chapter 6).

800

B9 EIM_TE 8 to 793544

Errored interval monitor parameter (see ITU-T Q703 A.10.2)

B10 EIM_UE 1 to 198384


B11 EIM_DE 1 to 11328


B12 JT_Q703_TE 20 to 30 (1 ms)

Defines the normalised time for error rate monitoring.

This parameter is relevant only in Japanese signalling networks.

JAPAN: 24

Parameter group




Table 11 Signalling link parameters (Cont.)

120 DN98785195




C MTP LEVEL 2 TIMER PARAMETERS

C0 Q703_T1 130 to 500 (0.1s)

Q703_T1, Alignment Completed timer ITU: 400

ANSI: 130

JAPAN: 150

C1 Q703_T2 50 to 5000 (0.1s)

Q703_T2, No Alignment timer ITU: 100

ANSI: 115

JAPAN: 50

C2 Q703_T3 10 to 116 (0.1s)

Q703_T3, Alignment timer ITU: 10

ANSI: 115

JAPAN: 30

C3 Q703_T4 23 to 95 (0.1s)

Q703_T4, Length of Test Period timer ITU: 82

ANSI: 23

JAPAN: 30

C4 Q703_T5 8 to 30 (0.01s)

Q703_T5, SIB Transmission timer ITU: 10

ANSI: 10

JAPAN: 20

C5 Q703_T6 30 to 72 (0.1s)

Q703_T6, Remote End Congestion timer ITU: 50

ANSI: 60

JAPAN: 30 for SEP, 50 for STP

C6 Q703_T7 5 to 20 (0.1s)

Q703_T7, Delayed Acknowledgement timer ITU: 10

ANSI: 15

JAPAN: 20

C7 Q703_T8 8 to 12 (0,01 s)

Errored interval monitor timer

C8 JT_Q703_TF 20 to 30 (1 ms)

Parameter group





DN98785195 121



Defines the interval for sending an FISU when there are no MSUs transmitted.


JAPAN: 24

C9 JT_Q703_TO 20 to 30 (1 ms)

Defines the interval for transmitting SIO and SIE messages used for initial set-up and during verification.


JAPAN: 24

C10 JT_Q703_TS 10 to 30 (1 ms)

Defines the interval of SIOS to be transmitted during sus-pension.


JAPAN: 24

D MISCELLANEOUS MTP LEVEL 3 PARAMETERS

D0 PERIODIC_LINK_TEST_DENIED YES, NO

Controlling the transmission of signalling link test mes-sages.

NO

D1 MAX_LENGTH_OF_SIF 62, 272

Maximum length of the SIF field in the MSU message. 272

D2 INHIBIT_ATTEMPT_LIMIT 1 to 5

Limit for repeated attempts to inhibit a link. 3

D3 INHIBIT_TEST_DENIED YES, NO

Controlling the inhibition of a test procedure. NO

D4 ECO_SENDING_ALLOWED YES, NO

Defines the control of the Emergency Changeover proce-dure.

ITU-T: YES

ANSI: YES

JAPAN: NO (NTT), YES (TTC)

D5 INHIBITION_DENIED YES, NO

Control of the link inhibition procedure. NO

D6 SIN_DENIED YES, NO

Control of the link alignment procedure. NO

D7 SIPO_DENIED YES, NO

Control of the local processor outage procedure. NO

D8 LINK_SUSPEND_DENIED YES, NO

Control of the link oscillation prevention procedure. YES

Parameter group





122 DN98785195




D9 FALSE_CONG_DENIED YES, NO

Control of the false link congestion detection procedure. YES

D10 LINK_SRT_DENIED YES, NO

Control of the signal routing test procedure. YES

E SIGNALLING CONGESTION CONTROL PARAMETERS

E0 CONG_FILTERING_TIME 10 to 100 (0.01s)

Defines the time after which continuing congestion on a signalling link is reported to level 3. This feature prevents the signalling traffic control procedures from starting during very short-time peakloads.

1

E1 BUFF_FILTERING_TIME 50 to 300 (0.01s)

Defines the time after which continuing congestion on a signalling link is reported to level 3 while signalling message buffering is active. This feature keeps the sig-nalling traffic control procedures from starting in special situations, such as changeovers, changebacks, and con-trolled reroutings.

1

E2 CONG_ONSET_THRESHOLD1 2 to 1000, NOT IN USE

Reports the occupancy of the transmission buffer that is interpreted as level 1 congestion. Congestion can be set for threshold values 0 to 127; if the value is 128 to255, the signalling link congestion is never on.

49 Limit for congestion onset (messages)

E3 CONG_ABATE_THRESHOLD1 1 to 800, NOT IN USE

Reports the occupancy of the transmission buffer that is interpreted as the ending for level 1 congestion (that has been on). It is advisable to set the release level of conges-tion clearly lower that the activation level to avoid vibra-tions.

2 Limit for congestion reset (messages)

E4 CONG_DISC_THRESHOLD1 0 to 2500, NOT IN USE

Reports the occupancy of the transmission buffer that makes the signalling terminal software set the signalling message destroying status on in the transmission mail box. When the CCSEND program block notices that the destroying status is set on, it destroys the signalling messages addressed to the mentioned signalling termi-nal. The threshold values for the destroying status are selected from the range 0 to 127; if the value is 128 to 255, the status is never set to ON. However, when the transmission buffer fills up, signalling messages have to be destroyed. The status value must therefore be higher than the limit for signalling link congestion in order to avoid unnecessary destroying of messages.

NOT IN USE Limit for message discarding (mes-sages)


Parameter group





DN98785195 123



CONG_ONSET_THRESHOLD2, CONG_ABATE_THRESHOLD2, CONG_DISC_THRESHOLD2, CONG_ONSET_THRESHOLD3, CONG_ABATE_THRESHOLD3, and CONG_DISC_THRESHOLD3 are similar to the above mentioned parameters when the used congestion control method has several levels. The parameter values on level 2 must be higher than the corresponding values on level 1, and also values on level 3 must be higher than those on level 2, in order to get the congestion method work properly with several levels. When the congestion method uses only one level, set the parameter values on levels 2 and 3 as 255 = 0FFH. See the E2, E3, and E4 parame-ters.

NOT IN USE


See the E5 and E3 parameters. NOT IN USE

E7 CONG_DISC_THRESHOLD2 10 to 2500, NOT IN USE






E10 ONG_DISC_THRESHOLD3 10 to 2500, NOT IN USE


E11 T111_T31_ONSET_THRESHOLD 1, 2, 3, NOT IN USE

Congestion threshold for starting timer T111_T31. NOT IN USE

E12 T111_T31_RESET_THRESHOLD 1, 2, 3, NOT IN USE

Congestion threshold for reseting timer T111_T31. NOT IN USE

E13 SL_LOAD_THRESHOLD 100 to 900

Allows a maximum value for signalling link load in Merlangs without notification.

F MTP LEVEL 3 TIMING PARAMETERS

F0 Q704_T1 5 to 12 (0.1s)

Delay to avoid message mis-sequencing on changeover. ITU: 8

ANSI: 8

JAPAN: 10

F1 Q704_T2 7 to 20 (0.1s)

Parameter group





124 DN98785195




Waiting for changeover acknowledgement. ITU: 14

ANSI: 14

JAPAN: 10

F2 Q704_T3 7 to 12 (0.1s)

Time-controlled diversion-delay to avoid mis-sequencing on changeback.

ITU: 8

ANSI: 8

JAPAN: 10

F3 Q704_T4 5 to 12 (0.1s)

Waiting for changeback acknowledgement (first attempt). ITU: 8

ANSI: 8

JAPAN: 10

F4 Q704_T5 5 to 12 (0.1s)

Waiting for changeback acknowledgement (second attempt).

8

F5 Q704_T12 8 to 12 (0.1s)

Waiting for uninhibition acknowledgement. 10

F6 Q704_T13 6 to 15 (0.1s)

Waiting for force uninhibit. 10

F7 Q704_T14 8 to 30 (0.1s)

Waiting for inhibition acknowledgement. 20

F8 Q704_T17 8 to 60 (0.1s)

Delay to avoid oscillation of initial alignment failure and link restart.

10

F9 Q704_T22 180 to 600 (1s)

Local inhibit test timer. 180

F10 Q704_T23 180 to 600 (1s)

Remote inhibit test timer. 180

F11 Q707_T1 8 to 120 (0.1s)

Waiting for signalling link test message acknowledge-ment.

80

F12 T111_T19 120 to 600 (1s)

Time supervision for setting an alarm about a signalling link that refuses to start up, as defined in ANSI standards.

120

F13 T111_T20 90 to 120 (1s)

Control for local inhibition testing as defined in ANSI stan-dards.

120

Parameter group





DN98785195 125



F14 T111_T21 90 to 120 (1s)

Control for remote end inhibition testing as defined in ANSI standards.

120

F15 T111_T31 10 to 120 (1s)

False link congestion detection timer. ITU: 10

ANSI: 30

F16 T111_T32 5 to 120 (1s)

Link oscillation timer - Procedure A 5

F17 JT_Q704_TS 0 to 600 (1 s)

Defines the time for transmitting SIOS on a periodical basis during suspension.


JAPAN: 30

F18 JT_Q707_T10 20 to 150 (0.1 s)

Waiting time for signal routing test confirmation. This parameter is relevant only in Japanese signalling net-works.

100

F19 ALIGN_RESP_WAIT 10 to 7000 (0.1 s)

Supervision time for inherently short alignment phases. 40

G ATM SPECIFIC PARAMETERS (SAAL LEVEL)

G0 Q2140_T1 2 to 60 (1 s)

Time between the link release action and the next link re-establish action during the alignment.

5

G1 Q2140_T2 10 to 120 (1 s)

Maximum time SSCF-NNI attempts alignment. 30

G2 Q2140_PROVING_LOAD 10 to 90 (%)

The load percentage of the signalling link during align-ment. SSCF–NNI T3 is derived from this parameter.

50

G3 Q2110_MAXCC 2 to 20

Maximum amount of time during which SSCOP tries con-nection establishment, release, resynchronisation, and rocovery.

4

G4 Q2110_MAXPD 50 to 1000

Maximum count of SD PDUs before SSCOP sends a poll. 500

G5 Q2110_TIMER_CC 50 to 1000 (1ms)

Parameter group





126 DN98785195




12.4 Signalling route set parametersThe parameters included in the parameter set of the signalling route set are used to handle the signalling functions of the signalling route set.

You can interrogate the values of the parameters of an existing signalling route set parameter set with the NNI command.

TIMER_CC ensures successfull SSCOP connection management actions. Maximum amount of time for which SSCOP waits for acknowledgement for connection estab-lishment, release, resynchronisation, and recovery PDUs.

200

G6 Q2110_TIMER_KEEP_ALIVE 100 (1 ms)

Timer to ensure that the peer SSCOP is still working in a transient phase when there are no SD PDUs to be trans-ferred.

100

G7 Q2110_TIMER_NO_RESP 100 to 3000 (1 ms)

Timer to recognise that the SSCOP connection is avail-able. Maximum amount of time for which SSCOP waits for STAT PDU.

1500

G8 Q2110_TIMER_POLL 10 to 100 (1 ms)

TIMER_POLL is running to assure that the peer SSCOP receiver is polled often enough.

100

G9 Q2110_TIMER_IDLE 100 to 3000 (1 ms)

TIMER_IDLE defines the time for SSCOP idle phase. At the expiry of TIMER_IDLE, the SSCOP enters the tran-sient pahase again.

100

G10 Q2110_MAXSTAT 10 to 200

Maximum number of list elements placed in a SSCOP STAT PDU.

67

G11 Q2144_MAXNRP 0 to 100

Maximum permissible SSCOP retransmissions during a proving attempt.

0

G12 Q2144_TIMER_REPEAT_SREC 10 to 300 (1 min)

TIMER_REPEAT_SREC is used to recognise closely spaced SSCOP connection recoveries. Minimum time between SSCOP connection recoveries.

60

G13 Q2144_TIMER_NO_CREDIT 100 to 5000 (1 ms)

TIMER_NO_CREDIT supervises the unavailability of SSCOP credit. Maximum time LM allowes SSCOP to be without credit.

1500

Parameter group





DN98785195 127



The parameters are divided into four groups (A-D):

A Common timers of all destinations

B Signalling point restart timers

C Adjacent signalling point parameters

D Common parameters of all signalling points

Table Signalling route set parameters lists the signalling route set parameters, their names, all possible values, the quality of the given value, and the recommended value, if any.



Parameter name Recommended value

A COMMON TIMERS OF ALL DESTINATIONS

A0 Q704_T6 5 to 20 (0.1s)

Delay to avoid message mis-sequencing on controlled rerouting. The parameter sets the time for waiting during controlled rerouting before traffic is activated to the desti-nation point through a new or alternative transfer point.

ITU: 8

ANSI: 8

JAPAN: 10

A1 Q704_T8 5 to 20 (0.1s)

Time supervision for inhibition of the Transfer Prohibited messages. The Transfer Prohibited messages generated by the reply system are not sent to the destination point, if other - similar - messages have been sent there during the time specified by the parameter.

10

A2 Q704_T10 10 to 120 (1s)

Time supervision for repetion of test messages in the sig-nalling route set. Test messages related to another signal-ling point are sent at intervals defined by the time parameter.

ITU: 31

ANSI: 31

JAPAN: 30

A3 Q704_T11 30 to 90 (1s)

Transfer Restricted time supervision. This parameter sets the time for which a signalling link set, which uses another signalling point as the transfer point, has to be faulty before it is set in state 'long-term failure'. When this state is set for a signalling link set, Transfer Restricted messages are sent to the adjoining signalling points. The messages concern all route sets where one of the primary routes are using the failed link set and where the traffic is now directed to secondary routes.

60

A4 Q704_T15 20 to 30 (0.1s)

Table 12 Signalling route set parameters

128 DN98785195




If within T15, after the reception of the last Transfer Con-trolled message related to destination X, signalling point Z receives another Transfer Controlled message related to the same destination, the following action is taken: If the value of the congestion status carried in the new Transfer Controlled message is higher than the current value of the congestion status of the signalling route set towards desti-nation X, then the current value is updated to the higher one. If T15 expires after the last update of the signalling route set towards destination X in a Transfer Controlled message related to the same destination, the signalling-route-set-congestion-test procedure is invoked.

25

A5 Q704_T16

JT_Q704_TC

14 to 25 (0.1s)

26 to 250 (0.1 s)

If within T16, after sending a signalling-route-set-conges-tion-test message, a Transfer Controlled message related to the concerned destination is received, the signalling point updates the congestion status of the signalling route set towards the concerned destination with the value of the congestion status carried in the Transfer Controlled message. If T16 expires after sending a signalling-route-set-congestion-test message without a Transfer Con-trolled message related to the concerned destination having been received, the signalling point changes the congestion status associated with the signalling route set towards the concerned destination to the next lower status.

ITU: 15 (for Q704_T16)

ANSI: 15 (for Q704_T16)

JAPAN: 200 (for JT_Q704_TC)

A6 T111_T18 2 to 20 (1s)

A signalling point starts the MTP restart procedure when its first link is in service on level 2. Restarting the MTP: if it has the transfer function, it starts the T18 timer.

3

B SIGNALLING POINT RESTART TIMERS

B0 * Q704_T21

ANSI_T111_T25

20 to 70 (1s)

Q704_T21: The waiting period before traffic is restarted through an adjacent signalling point. Traffic on the routes using the adjacent signalling point is started only when the time defined in this parameter has past after the restart of the adjacent point (or when the point has sent the Traffic Restart Allowed message).

T111_T25: Waiting for the Traffic Restart Active message.

Blue Book 31

White Book 64

ANSI 64

B1 T111_T28 3 to 35 (1s)




Table 12 Signalling route set parameters (Cont.)

DN98785195 129



Signalling point X starts the T28 timer either when the first signalling link goes into 'in service' state on level 2, or when the first signalling link becomes available on level 3.

This parameter is used only in networks built according to the ANSI standards.

30

B2 Q704_T19_WHITE

T111_T29

60 to 80 (1s)

Supervision timer during the MTP restart to avoid possible 'back and forward' of TFP, TFR, and TRA messages.

68

B3 * T111_T30 20 to 40 (1s)

If the receiving point has the transfer function, it starts the T30 timer, and sends a Traffic Restart Waiting message followed by the necessary Transfer Restricted and Transfer Prohibited messages (preventive Transfer Pro-hibited messages are required for traffic currently being routed via the point from which the unexpected Traffic Restart Allowed or Traffic Restart Waiting messages were received) and a Traffic Restart Allowed message.

ANSI: 30

C ADJACENT SIGNALLING POINT PARAMETERS

C0 * TRM_DENIED YES, NO

The use of message pair TRA/TRW is denied in network management. In an ANSI network, the use of TRW in con-nection with the SP restart is denied.

ITU: NO

ANSI: NO

JAPAN: YES

C1 * TRM_EXPECTED YES, NO

This parameter controls the use of message pair TRA/TRW:

TRA_EXPECTED means that traffic restart is allowed. It controls the waiting for message reception when the sig-nalling link set is taken into use.

TRA_WAITING controls the waiting of message reception when the signalling link set is taken into use.

TRA_DENIED means that sending of the Traffic Restart Allowed messages is denied.

ITU: YES

ANSI: YES

JAPAN: NO

C2 * SP_RESTART_TYPE BLUE, NONE, WHITE, ANSI

Controlling the denial of the signalling point restart proce-dure. When the usage of the procedure is denied, the restart procedure of the adjacent signalling point is not used. When the own signalling point is restarted, the Traffic Restart Allowed message is not sent to the adjacent SP, either.

ITU: BLUE

ANSI: ANSI

JAPAN: NONE





130 DN98785195




C3 * INDIRECT_ROUTES_DEFAULT AVAILABLE, RESTRICTED, UNAVAILABLE, TFM BASED

Parameter for controlling the signalling link set restarts when the adjacent SP has not been started. The possible parameter values are available, restricted, unavailable, and TFM-based.

ITU: AVAILABLE

ANSI: AVAILABLE

JAPAN: AVAILABLE

C4 * TFM_CONTROL ALL ALLOWED, BROADCAST DENIED, ALL DENIED

Control parameter for broadcasting messages: Transfer Allowed, Transfer Restricted, and Transfer Denied. When the parameter denies broadcasting of messages and an SP becomes either available or unavailable, it is not reported to the adjacent SP.

ALL ALLOWED

C5 * RESP_TFM_CONTROL TFR ALLOWED, TFP ALLOWED, TFP FOR KNOWN, TFM DENIED

Control parameter for response method messages. The possible parameter values are 'TFR allowed', 'TFP allowed', 'TFP for known', and 'TFN denied'.

ITU: TFP ALLOWED

ANSI: TFR ALLOWED

JAPAN: TFP ALLOWED

C6 * TFR_DENIED YES, NO

Control parameter for the use of the Transfer Restricted procedure. If the use of the procedure is denied, the Transfer Restricted messages coming from the source point are not handled, and Transfer Restricted messages are not sent to the destination point. Instead, the system sends Transfer Allowed messages (unless their use is also denied).

ITU: YES

ANSI: NO

JAPAN: YES (TTC), NO(NTT)

C7 * M3UA_PSTN_IMPLICATION ALIGN, FAIL

Alignment of PSTN link sets when designated M3UA link sets are unavailable.

C8 * SOR_REF_WITH_NODE_INFO YES, NO

Indicates whether local reference identifiers of connection oriented SCCP messages include also signalling point info.

D COMMON PARAMETERS OF ALL SIGNALLING POINTS

D0 TFR_SENDING_BASIS NONE, ITU, ANSI

Control parameter for managing overload on a spare route when the last available route becomes unavailable. The possible parameter values are NONE (no TFR messages broadcast), ITU (follows ITU-T Rec. Q704), and ANSI (examines state of the T11 timer).

ITU: NONE

ANSI: ANSI

JAPAN:ITU





DN98785195 131



D1 CIRC_ROU_PREV_IN_USE YES, NO

Control parameter for restricting the possibilities of the occurrence of circularly routed messages. When this parameter has the YES value, an extra Transfer Prohibited message is used concerning one of the destination signal-ling points. If traffic to the point goes through alternative routes, the system sends the Transfer Prohibited message about that point to all adjacent signalling points, and orders them to switch all traffic to the point through other signal-ling points.

ITU: NO

ANSI: YES

JAPAN: NO

D2 TFC_DENIED YES, NO

Control parameter for the sending of the Transfer Con-trolled message. If the parameter has the value NO and denies message sending, Transfer Controlled messages are not sent to the destination point.

NO

D3 CONG_LEVEL_SUPPORT NONE, TFC, TFC AND RCT

Control parameter for the encoding of the congestion level of Transfer Controlled messages. If the parameter has the value NO and the message control is inactive, the system sets congestion level 0 for the TFC messages directed to the destination point, but otherwise they get a congestion level as defined by the overloaded signalling terminal. This control parameter can also be used to define the overload of a destination point to be monitored, using the Conges-tion Level Test messages.

ITU: TFC

ANSI: TFC AND RCT

JAPAN: TFC (NTT), TFC AND RCT (TTC)

D4 CONFUSION_MSG_DENIED YES, NO

Control parameter for the sending of the MTP Confusion message. If sending of the messages is prohibited, the messages are not transmitted to the destination point. This feature is implemented as defined in the BTNR 146 Stan-dard.

YES

D5 UPU_ALLOWED YES, NO

This parameter either allows (YES) or denies (NO) the sending of the UPU message (user part unavailable).

ITU: NO

ANSI: YES

JAPAN: NO

D6 RST_ON_TFP_ALLOWED YES, NO

This parameter either allows (YES) or denies (NO) imme-diate sending of Route Set Test (RST) messages when a Transfer Prohibited message (TFP) is received. When this parameter has the NO value, the RST message is sent after the Q704_T10 timer has expired.

ITU: YES

ANSI: YES

JAPAN: NO

D7 SUPPORT_OF_M3UA_SNM YES, NO





132 DN98785195




* The parameters are significant only to the local signalling points.

12.5 SCCP signalling point parametersThe parameter set related to the SCCP signalling point defines the parameters for certain timers that are used in monitoring the signalling connections, and for managing the subsystems (ITU-T Recommendation Q.714). The parameter set also defines some of the signalling network functions.

The parameter values vary according to the release level and delivery. Usually, the default parameter values are suitable and it is not necessary to change them. But the values can be changed if, for example, the national definition of signalling differs from the set default values.

You can interrogate the values of the parameters of an existing SCCP signalling point parameter set with the OCI command.

Table SCCP signalling point parameters lists the parameter names, all possible param-eter values, the quality of the value, and the recommended values, if any, which are related to the SCCP signalling point.

Control of sending M3UA signalling network management messages.

D8 USE_OF_M3UA_NW_APP YES, NO

Control of using the Network Appearance parameter in M3UA signalling network management messages.





Paramete number

Parameter nameParameter explanation

Value range (quality of value)Recommended value

1 Q714_T_CONN_EST 30 to 240 (1s)

Timer for connection setup. Defines the time for waiting for a response to the connection request message.

90

You do not need to change the parameter value.

2 Q714_T_IAS 60 to 600 (1s)

Send inactivity timer. When the set timer expires, an inactivity test-message (IT) is sent to the connection section.

90

This timer should normally be at least two times smaller than Q714_T_IAR at the other end.

3 Q714_T_IAR 150 to 1260 (1s)

Table 13 SCCP signalling point parameters

DN98785195 133



Receive inactivity timer. Connection is released if no messages have been received when the timer expires.

270

This timer should normally be at least two times greater than Q714_T_IAS at the other end.

4 Q714_T_REL 100 to 200 (100ms)

If the first connection release message (Released, RLSD) produces no acknowledge-ment (release message or Release Completed, RLC), the release message is repeated and new time supervision is started for it (Q714_T_REP_REL).

150

5 Q714_T_INT 45 to 90 (1s)

Control parameter for connection release time. The release message is being repeated during that time. After the time-out, the resources allo-cated for the connection are frozen for a certain time and an alarm is set.

60

6 Q714_T_RES 10 to 20 (1s)

Time supervision for resetting the signalling connection: service class 3 timer that is not in use.

15

7 Q714_T_REP_REL 40 to 200 (100ms)

If a repeated connection release message (Released, RLSD) produces no acknowledge-ment (release message or Release Completed, RLC) during the set time supervision period, the release message is repeated and new time supervision is started for it (Q714_T_REP_REL).

100

8 Q714_T_STAT_1ST 50 to 600 (100ms)

Time supervision, after which the first Subsys-tem Status Test (SST) message is sent out.

100

9 Q714_T_STAT_INC 150 to 3000 (100ms)

Time that is added to the repeat interval of the SST message after each repeat event, unless the message Subsystem Allowed (SSA) is received.

300

10 Q714_T_STAT_MAX 600 to 12000 (100ms)

The maximum time for the repeat interval of the SST message.

9000

11 A_INTERFACE YES, NO

Defines whether the system uses the A inter-face specification in the direction of the SP.

YES for A interface

NO for other interfaces

12 WHITE_BOOK_MGMT_USED YES, NO

Paramete number



Table 13 SCCP signalling point parameters (Cont.)

134 DN98785195




Defines whether the system uses the SCCP management procedures ITU-T Q711-Q714, 1993/3 (defined in the White Book) in the direc-tion of the SP.

NO

13 SS_MANAGEMENT_USED YES, NO

Defines whether subsystem status manage-ment functions are used.

YES

14 XUDT_USED YES, NO

Defines whether Extended Unit Data (XUDT) messages can be sent to the mentioned SP. The parameter value is read from the parameter set of the called SP.

NO

15 UDT_DENIED YES, NO

Defines when the sending of Unit Data (UDT) messages to the mentioned SP are denied. The parameter value is read from the parameter set of the called SP.

NO

16 SEG_X_THRES 1 to 272

The local segmentation threshold value is X for connectionless messages. The parameter value defines the length of the data part in the connectionless messages that are sent to the network. The X value can define segmentation if the value is smaller than Y depending on the local implementation. (This feature is not yet in use.)

272

Usually, this parameter has the same value as the SEG_Y_THRES parameter.

17 SEG_Y_THRES 67 to 272

Threshold value Y for the segmentation of the connectionless messages. The value can be used to adjust the length of data part in the con-nectionless messages that are sent to the network. The Y value mainly controls the seg-mentation.

272

Usually, this parameter has the same value as SEG_X_THRES parameter.

18 TCAP_LOAD_SHARING_USED YES, NO

Defines whether load sharing is used on TCAP messages. Load sharing applies only to messages that start a TCAP transaction. Load sharing means that the SCCP connectionless service distributes the TCAP messages coming from the network to the TC units in a circular sequence. The parameter value is read from the parameter set of the SP that has sent the message.

NO

It is advisable to use the YES value for this parameter if the traffic coming in to the CCSU is not evenly distributed.

19 ADD_DPC_IF_RI_SSN YES, NO

Paramete number




DN98785195 135



Defines whether a signalling point code has to be added or left in the called address when routing is done according to the subsystem number. Adding the code is only possible with messages going out into the network. The parameter value is read from the parameter set of the called SP.

NO

You do not need to modify this parameter value.

20 ADD_GT_IF_RI_SSN YES, NO

Defines whether a global title has to be left in the called address when routing is done according to the subsystem number. Adding the address is only possible with messages going out into the network. The parameter value is read from the parameter set of the destination SP.

NO


21 ADD_DPC_IF_RI_GT YES, NO

Defines whether a signalling point code has to be added or left in the called address when routing is done according to the global title. Adding the code is only possible with messages going out into the network. The parameter value is read from the parameter set of the destination SP.

NO


22 ANALYSE_ROOT_OF_CALLING_GT YES, NO

The parameter indicates if the global title root of calling address is analysed or not.

NO

23 ALLOWED_GTI_VALUES 1 to 15

The parameter declares the global title indicator values the use of which is allowed in calling address.

ITU-T: 1-4

ANSI: 1-2

ETSI: 4

ALL: 1-15

24 SSA_FILTER_TIMER 5 to 3000 (100 ms)

Defines the delay of local broadcast of Subsys-tem Allowed (SSA) state information.

10

25 SSP_FILTER_TIMER 5 to 3000 (100 ms)

Defines the delay of local broadcast of Subsys-tem Prohobited (SSP) state information.

10

26 LUDT_USED YES, NO

Defines whether the long unit data (LUDT) messages are used. Remote SP must support this function.

NO

27 CO_SEGM_USED YES, NO

Usage of connection-oriented segmentation.

28 GT_ADDR_FIXED_LEN YES, NO

Paramete number




136 DN98785195




12.6 SCCP subsystem parametersThe parameter set related to the SCCP subsystems defines, for example, the timers monitoring the various subsystems.

The parameter values vary depending on the release level and delivery. Usually, it is not necessary to change the parameter values. But, for example, if the national definitions on signalling are different from the default values, the parameter values can naturally be modified.

You can interrogate the values of the parameters of an existing SCCP subsystem parameter set with the OCJ command.

Table SCCP subsystem parameters lists the parameter names, possible parameter values, the quality of the given parameter value, and the recommended values, if any, for parameters related to the SCCP subsystems.

Indicates whether the called GT space reserva-tion is optimised in the (X)UDT message. If the parameter value is YES, no extra space is reserved for the GT expansion due to the GT modifications in the intermediate nodes. The parameter concerns messages coming from a local SCCP user. The parameter value is set in the parameter set of the destination signalling point.

NO

Paramete number




Parameter number



1 Q714_T_COORD_CHG 30 to 240 (1s)

The time supervision period spent waiting for a reply (Subsystem-Out-of-Grant, SOG, message) as an acknowledgement to the Sub-system-Out-of-Service-Request (SOR) message when the subsystem is being removed from service in a controlled manner.

90

2 Q714_T_IGN_SST 30 to 300 (1s)

Time supervision during which the SST message is not answered after receiving an SOG message.

60

3 A_INTERF_APPLIC YES, NO

Defines whether the A interface specification parameter of an SP is applied for this subsys-tem.

NO

4 A_INTERF_ERR_IGNORED YES, NO

Table 14 SCCP subsystem parameters

DN98785195 137



Defines whether the system ignores Protocol Data Unit Errors (ERR) received from the A interface.

NO

5 TRANSLATION_SELECTION SCCP, REDIGO

Defines where the global address is modified if the SCCP routing address (the result of the modification) is the own SP. Routing is made according to the global address. The parameter value is read from the parameter set of the called subsystem.

SCCP

6 CALLING_ADDR_MODIFICATION YES, NO

Defines whether the calling address is modified if the routing is based on the subsystem number when the global address has been modified and the message has been received from the SCCP user. In the calling address, the global title is replaced with the own point code. The parame-ter value is read from the parameter set of the calling subsystem.

NO

7 CSCC_ALLOWED_OUT YES, NO

Defines whether the subsystem is allowed to request coordinated state transition.

NO

8 CSCC_ALLOWED_IN YES, NO

Defines whether the request on coordinated state transition is sent to the subsystem.

NO

9 TRANSLATE_AT_DPC_IF_DPC_SSN_GT YES, NO

Defines whether the global title is translated in the SP, the signalling point code of which is included in the called address or a message is sent to the SP so that the routing indicator is routed on SSN, although the called address also includes the GT when the called address of the incoming message includes a signalling point code, subsystem number, and global title. This parameter only applies to the messages received from the own user part. The parameter value is read from the parameter set of the called subsystem.

YES

10 TC_TRANSACTION_IDS_THRESHOLD 25 to 90 (%)

Threshold for open TC transaction. If the thresh-old is exceeded, a statistics event log is set.

75

11 SEND_CALLING_SSN_IF_RI_SSN YES, NO

Indicates whether the calling address is modified so that it includes only the SSN when the routing of the called address is based on SSN.

NO

Parameter number



Table 14 SCCP subsystem parameters (Cont.)

138 DN98785195




12 SEND_CALLING_SPC_SSN_IF_RI_GT YES, NO

Indicates whether the calling address is modified so that it includes the SPC and SSN when the routing of the called address is based on the GT.

NO

13 KEEP_CLD_GT_IF_RI_SSN YES, NO

Indicates if the GT is kept in the called address, even if routing of the called address is based on SSN. The parameter concerns messages going to a local SCCP user.

NO

14 IMMEDIATE_STATE_INFO YES, NO

Indicates whether subsystem state information is transferred immediately to a local SCCP user.

NO

15 TC_PROTOCOL_VERS_EXCLUDED YES, NO

Indicates whether the optional protocol version field is included in the outgoing TCAP message. If the parameter value is YES, the protocol version field is not included. The parameter concerns messages coming from a local TC user. The parameter value is set in the parame-ter set of the calling subsystem.

NO

16 GT_RES_SPEC_HDL_RI_SSN YES, NO

Indicates whether the SCCP actions relating to the enhanced virtual subscriber feature in HLR are applied to an SCCP subsystem. SCCP actions mean applying GT analysis to a message with address GT+SPC+SSN (RI=SSN) to obtain the value of a GT result attri-bute named special_handling. parameter value is defined in the parameter set of the called sub-system.

Parameter number



Table 14 SCCP subsystem parameters (Cont.)