gemini abis and transport solutions v1 8 ppt

1 © Nokia Siemens Networks RN22012EN20GLA1

Gemini Abis and transport solutionsRN2201-20A


Nokia Siemens Networks Academy

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Module Objectives

After completing the module, the student will be able to:

• Describe GEMINI Abis solutions– LAPD multiplexing in GEMINI

– LAPD redundancy concept

– LAPD overload handling

• Know about GEMINI transport solutions– supported Abis configurations

– physical interfaces and BTSplus HW aspects

– BR synchronization feature

• Get an overview of the transport evolution and scenarios in RG20


Gemini Abis solutions


Abis in GEMINI

• Abis (towards FlexiBTS => “Dynamic Abis”)– GEMINI does not affect Dynamic Abis at all, its

concept is fully maintained, no adaptation to the existing implementation needed (refer to here for overview)

• Abis (towards BTSplus => “Dynamic Abis for BTSplus”)

– Abis adaptation consisting in replacement of Flexible Abis with Dynamic Abis principles is needed

– Dynamic Abis concept is reused for CS/PS traffic while LAPD multiplexing concept is kept for signaling traffic

– Such configuration of Abis is hereafter referred to as Dynamic Abis for BTSplus

Abis-BR

RC

BSxx

BSxx

NetAct

Flexi

Flexi

O-link Q3

eBSC BSC3i

Abis-BSS

Abis-BSS

Abis-BR

Abis-BSS (*)

Abis-BSS (*)

BR-LMT

BR-LMT

BSxx

BSxx

Abis-BSS (*)BSS Abis applies apart from e .g. HO and Power Control issues , which cannot be adapted due to BSxx constraint

Ref. S. Basile, GEMINI master SFSNovember 2008, version 1.0.1

Connection of FlexiBTS to BSC3i/FlexiBSC bringsin RG10 no news on Abis in comparison to

previous BSS programs (Dynamic Abis is in use).

Connection of BTSplus to BSC3i/FlexiBSC introduces in RG10 a new concept for BSC that is

LAPDmux (Dynamic Abis for BTSplus is in use).


GEMINI overviewFunctional feature description

• Network Architecture in GEMINI

Flexible AbisBTSplus

MetroSite BTS

Dynamic Abis

NetAct

BTSplusFlexible Abis Radio Commander

FlexiBTSFlexiBSC

family product

Radio Commander

BTSplus

Dynamic Abis

for BTSplus

UltraSite BTS

BSC1 / eBSC

BSC1 / eBSC

No HW change necessary to introduce Dynamic Abis at BTSplus base station FlexiBSC product family provides high capacity and flexibility BTSplus and UltraSite BTS can be fully utilized

NetAct serves as common management system and reduces OPEX Ref. PLM, RG Release secures Customer Investment, November 2008: modified by author

Dynamic Abis Dynamic Abis


LAPD multiplexing in GEMINIoverall aspects

•LAPD multiplexing aims at optimizing usage of the LAPD channels by reduction of required signaling bandwidth

• Up to now on Abis interface controlled by the BSC3i/FlexiBSC a dedicated LAPD signaling channel is foreseen for each TRX

• In GEMINI, when BSC3i/FlexiBSC controls BTSplus, several TRXs can be multiplexed in the same LAPD (just like for Flexible Abis), allowing all the TRXs belonging to the same site to be configured on one common physical LAPD link

Each logical LAPD link called TRXSIG has its own physical channel created on PCM line

Several logical LAPD links are multiplexed within a single physical channel created on PCM line


LAPD multiplexing in GEMINIimplementation overview

•up to 11 LAPD links per BTSplus are configurable for TRX signaling and O&M part– several TRXs (i.e. TRXSIG channels) are multiplexed in a single physical LAPD link

– OMUSIG channel is also multiplexed in one of physical LAPD links

– up to 16 logical LAPD connections can be multiplexed into one physical LAPD link (upper limit)

– the actual number of logical connections per physical link is subject to dimensioning (as it depends on many factors: site configuration, traffic profile, LAPD link capacity, …)

• physical LAPD links can have capacity of 16 kbps or 32 kbps or 64 kbps– physical LAPD links with different bitrates can be created within the same site

(impossible in BR implementation as well as the usage of 32 kbps physical LAPD links)

– each Abis line needs to have (at least) 1 physical LAPD link created, several physical LAPD links can be created onto a single PCM line (but a single physical link must not be spread over several PCM lines)

• existing (BSS) LAPD related objects are used in GEMINI to manage LAPD multiplexing– distribution of TRXSIG/OMUSIG among available physical LAPD links is done manually

up to 16 logical LAPD channels per physical link(each TRXSIG/OMUSIG corresponds to a single logical LAPD connection)

up to 11 physical LAPD links per site


LAPD multiplexing in GEMINIimplementation overview

• LAPD multiplexing is feature of LAPD protocol which, for each logical connection that is multiplexed into common physical LAPD link, assures:

– independent message flows with their own sequence control,

– flow control, re-transmission, re-synchronization, …

• Each logical LAPD connection inside a physical LAPD link is unambiguously identified within site by TEI+SAPI pair

• The following coding is in use for LAPD multiplexing in GEMINI:– OMUSIG: SAPI = 62, TEI = 1

– TRXSIG: SAPI = 0, TEI = TRX-id

• When LAPD multiplexing is in use then all TRXSIG and OMUSIG channels sharing the same physical link, must be configured to the same BCSU unit (and the same signaling terminal AS7):

– it means that in GEMINI all TRXs belonging to given BSxx must be assigned to the same BCSU and AS7 (when they are mapped to a single LAPD link)

TEI: Terminal Endpoint IdentifierSAPI: Service Access Point Identifier

fixed ID, not configurable

implicitly known ID, retrieved automatically based on TRX-id

all TRXSIG/OMUSIG that are multiplexed in the same physical LAPD link must have: -> the same BITRATE (cf. command ZDSE) -> the same BCSU-id (cf. command ZDSE) and LOG TERM-id (by means of AS7 resource manager)


LAPD multiplexing in GEMINILAPD related attributes

•Pre-defined set of LAPD attributes is defined to simplify configuration of LAPD links for FlexiBTS and BTSplus

Parameter Description

Parameter Set Number object: LAPD

range: 0 (Standard Abis setup) 1 (Satellite Abis setup) 2 (BTSplus Abis setup) 3 (BTSplus Satellite Abis setup) 4 (IP Abis setup 1) 5 (IP Abis setup 2 - for long delays),6 (IP Abis setup 3 - for low quality lines) default: 0MML command: DSE

Parameter Set Number (parameterSetNumber), with this parameter you define the used predefined parameter set of LAPD in LAPD creation.

The number of I-frames that may be sent without any acknowledgement from

the opposite side

“No response” timer: defines timeout for initiating retry or declaring failure.

“No traffic” timer: defines timeout for initiating link integrity check (if no traffic received in the

meantime).

Max number of frame retransmissions: when no acknowledgement received after

T200 * (N200 + 1) ms then an ERROR INDICATION with cause 'T200 expired N200+1 times' is sent

Max frame size in an information field

Note: For FlexiBTS in addition to the values reported in the table above it is possible to have the following set of LAPD attributes: Parameter Set 0, SAPI = 61: window size = 1, T200 = 40 ms, T203 = 10 s, N200 = 18, N201 = 260Parameter Set 1, SAPI = 61: window size = 1, T200 = 40 ms, T203 = 10 s, N200 = 18, N201 = 260


LAPD multiplexing in GEMINILAPD redundancy

• TRXSIG concept– after failure of physical LAPD where BCCHTRX has its TRXSIG, BSC3i will move BCCH to other TRX (which

has its TRXSIG running) leading to loss of another (non-BCCH) TRX a TRXSIG failure is not indicated via alarm, only a warning (12316) is logged in the BTS internal alarm buffer

– in case of PCM failure the concept is only efficient when we have 2 PCM lines per site and TRXSIG are distributed over both PCM lines

– failure of the physical link where TRXSIG related to non-BCCH TRX is mapped triggers no recovery action...

• OMUSIG: no redundancy– after failure of physical LAPD link where OMUSIG was mapped, the BSC3i will not do any recovery actions

an OMUSIG failure will trigger the alarms: 12318 (LAPD link protocol failure), 7706 (BTS and O&M link failure) and 7704 (PCM failure).

SAPI0, TEI0

LAPD1

LAPD2

BTSplus

cell1

cell2

cell3

BCCH TRX0

BCCH TRX3

BCCH TRX6

TRX1 TRX2

TRX4 TRX5

TRX7 TRX8

BSC3iGEMINI

SAPI0, TEI1SAPI0, TEI3SAPI0, TEI4

SAPI0, TEI8

SAPI0, TEI2SAPI0, TEI5

SAPI0, TEI6SAPI0, TEI7

SAPI62, TEI1

After failure of LAPD2 the 3rd cell’s BCCH is moved to TRX8


LAPD multiplexing in GEMINILAPD overload handling

•uplink (stepwise mechanism):– Step 1: smooth reduction of measurement results (MR) messages

– load of LAPD links estimated on the basis of LAPD usage (the number of bytes which are transmitted over Abis during predefined period of time) computed every LAPDOVLT0 sec

– lower and upper load thresholds defined and depending on LAPD usage the actual MR load is subject to REDUCTION (MR messages are discarded randomly irrespective of their purpose and origin)

USG > firstLevelUpperThreshold then REDUCTION = 100 (i.e. all MR are discarded)

firstLevelLowerThreshold < USG ≤ firstLevelUpperThreshold then REDUCTION = min(100, REDUCTION + firstLevelReductionStep)

firstLevelLowerThreshold ≥ USG then REDUCTION = max(0, REDUCTION - firstLevelReductionStep)

firstLevelUpperThreshold

firstLevelLowerThreshold

LAPDOVLT0 [sec]

USG [%]

Initial state: REDUCTION = 0

Parameter settings:LAPDOVLT0 = 1 secfirstLevelReductionStep = 10

REDUCTION [%] =

max(0,0-10)

0

max(0,0-10)

0

min(100,0+10)

10

min(100,10+10)

20

min(100,20+10)

30

100

100

100

100

100

100

min(100,100+10)

100

min(100,100+10)

100

min(100,100+10)

100

min(100,100+10)

100

min(100,100+10)

100

max(0,100-10)

90 80

When upper threshold is exceeded (even for a while) then all MR are discarded until usage drops below lower threshold.Next, MR load is ramped up stepwise until usage exceeds lower threshold.After that, MR load is ramped down stepwise...



•uplink (stepwise mechanism):

– All parameters that control LAPD overload handling are hardcoded in GEMINI. These are:

FLAPDOVLTH:firstLevelLowerThreshold = 60% (referred to as “1L” in the figure above)firstLevelUpperThreshold = 80% (referred to as “1H” in the figure above) firstLevelReductionStep = 10%

LAPDOVLT0 = 1 secSLAPDOVLTH:

secondLevelLowerThreshold = 80% (referred to as “2L” in the figure above) secondLevelUpperThreshold = 90% (referred to as “2H” in the figure above)

– There are 2 parameters introduced in GEMINI to control rate of MR messages. These are: SDCCH MR Sending, Interval MR Sending.

1L 1H 2L 2H0% 100%

ramp up MR load- with step of 10%/sec- except init phase

ramp down MR load- with step of 10%/sec- expect the case just after 1H exceeding(when MR load is totally discarded)

suspend MR load

LAPD overload- discard low/medium prio messages



•uplink (stepwise mechanism):

– Step 2: priority based discarding messages (2L ↔ 2H) – three priority levels defined for LAPD messages

– high prio messages are not discarded– medium and low prio messages are discarded when queue length exceeds hardcoded limits

(of 45 and 30 messages, respectively) => these messages should be sent in unacknowledged mode (in UI-frames)– no degradation of call processing will be observed if measurement results are lost– any loss of channel required messages is compensated by the MS itself (as it re-sends Random Access

if no response from the BTS is received within the specified time)

HIGHall TELECOM messages

MEDIUMCHAN_REQ

LOWTMEASRES, MEAS_RESULT

1L 1H 2L 2H0% 100%



suspend MR load




• uplink (stepwise mechanism):

– Step 3: all frames which do not fit in transmit queues are discarded, no re-ordering or selection of certain message types performed (2H ↔ 100%)

– Note: LAPD overload message is not sent to BSC in GEMINI

• downlink:– main reason for overload: paging load

– BSC observes its transmit queues, when they reach certain length paging and immediate assignment reject messages are discarded

– LAPD overload in DL is also additionally prevented by BCSU processor overload protection mechanism

1L 1H 2L 2H0% 100%



suspend MR load



BCF

BTS

BCFSIG

TRX

TRX

BTS

TRX

TRX

TRXSIG

TRXSIG

TRXSIG

TRXSIG

Logical Objects for Abis creation with BTSplus

Configuration steps:• Create LAPDs

– one BCFSIG and a TRXSIG for every TRX in same physical PCM timeslot

• Create BCF and attach BCFSIG• Create BTS• Create TRX and attach TRXSIG

Multiplexed LAPD


Gemini transport solutions


GEMINI transport solutionssupported physical interfaces

• E1/T1 transmission system is available as transport interface between BSC and BTSplus in GEMINI– no changes needed at BTS/BSC side to establish Abis over E1/T1 (standardized electrical parameters, line

coding, frame format, etc.)

– both terrestrial or satellite links are possible

– BTSplus can control in GEMINI up to 8 E1/T1

• Although BTSplus supports only E1/T1 interfaces in GEMINI, these E1/T1 links can be tributaries of a higher order networks like e.g. SDH => leads to more possibilities for backhaul configuration:

– channelized SDH can be used at BSC side, E1/T1 at BTS side, and an SDH DXC in between

– hiD-based Abis optimizer (tests are ongoing)

– please note that CESoPSN (either via integrated IP cards or hiD-based) is not supported in GEMINI

• Connection between BTSplus and FlexiBSC is established in GEMINI using Dynamic Abis for BTSplus

– due to difference in bandwidth efficiency between Flexible Abis and Dynamic Abis additional transmission capacity is needed for a percentage of sites

– the number of affected sites depends on site configuration and traffic profile

• GEMINI does not affect the way in which FlexiBTS can be connected to BSC


GEMINI transport solutionssupported Abis configurations

• The following Abis configurations are supported in GEMINI:

star– p2p connection between BSC and one BTS site, one or more E1/T1 lines can be used to establish the connection

BTSplus

PCM2

E1/T1

FlexiBSC

P0

P2PCM1

PCM0

E1/T1

P0

BTSplus FlexiBTS

LIF1E1/T1

PCM3

multidrop– an E1/T1 line (or bundle of lines) can be shared between two or more different sites

– mixing up BTSplus/FlexiBTS in a given multidrop is allowed in GEMINI (this does not denote co-location)

– in multidrop configuration a FlexiBTS reset affects all the following sites on the chain while a BTSplus reset does not

E1/T1E1/T1„1st“ BTSplus

E1/T1

FlexiBSC

P0

P2

P4

P6

P1

P3

„2nd“ BTSplus

FlexiBTS

LIF1

PCM1

PCM2

PCM3

PCM0P0

P2

P1

P3PCM1

PCM0



•The following Abis configurations are supported in GEMINI:

x-connect– out of a star/multidrop PCM TSL(s) (i.e. @64k) can be “extracted and inserted” into another E1/T1 line starting at the cross connecting BTS

– mixing up BTSplus/FlexiBTS is allowed in GEMINI

E1/T1

E1/T1„1st“ BTSplus

E1/T1

FlexiBSC

E1/T1

P0

P2

P4

P6

P1

P3

„2nd“ BTSplus

„3rd“ BTSplusFlexiBTS

P0

P1

P0LIF1

PCM1

PCM2

PCM3

PCM0

“cross-connecting” site



• Loop configuration, used in BR, is not supported in GEMINI

„1st“ BTSplus

P0

P2

P4

P6

P1

P3

„2nd“ BTSplus

„3rd“ BTSplus

P0 P1

P0

BSC (BR)

…xTLPLIET

PORT0

PORT1

PORTn P1

P2 P3

P2 P3

PORT0Trunk A

PORT0Trunk B


GEMINI transport solutionsBTSplus HW aspects

• No HW upgrade is necessary in BTSplus due to GEMINI

• COBA is main BTSplus HW unit responsible for: – management of the entire BTSE (inc. LAPD routing) (BCC / MEM)

– call processing and interconnection management between CU and Abis (CULIC)

– PCM connectivity (FALC)

– BTSE traffic handling (inc. alarms, serial IF) (SIF)

– BTSE clock generation (i.e. signal for COBA/COSA/CU) (ACLK)

• BISON (Bit Switch for Optimized access Network) is one of modules inside CULIC– switching part of COBA / COSA responsible for connection between FALC ↔ BSS ↔ CU

• BISON can control simultaneously up to 8 master channels plus 48 slave channels– this determines the max size of EDAP for BTSplus in GEMINI: 12 PCM TSL

– the max number of EDAP pools for BTSplus is not defined, only the total number of slave channels is specified per COBA type

– COBA2P8: 48 channels => 12 TSL for all EDAP pools

– COBA4P12: 240 channels => 60 TSL for all EDAP pools

• GEMINI does not affect the max EDAP size (or the number of EDAPs) for FlexiBTS product:– up to 24 PCM TSL for FlexiBTS

– up to 12 PCM TSL for UltraSite / MetroSite

Note! Simplified picture

to give overviewCOBA

CULIC

BCC

FALC

SIF

ACLK

MEM

to CU

to Abis

CU Link Interface Controller

Base Core Controller

Framing And PCM Line Controller

Advanced CLocK generator

System Interfaces

MEMory


GEMINI transport solutionssupported BR synchronization feature

• There is a feature addressing synchronization aspects inherited by GEMINI from BR– this is BTSplus sync by 1pps signal

– it is only relevant for BTSplus and is not supposed to be supported by FlexiBTS

• The only attribute related to the feature (syncSource) is related to SYNCBTSE object (not relevant for BSC, configurable at BTS HW level by means of LMT, i.e. just like in BR)

Parameter name (abbreviation)

Range and step, default value

Description Object name

syncSource (SYNCSRC) Type: stringValues: abis, extGPS, ext_1pps_onlyDefault: abis

Defines the synchronisation source.Note:By setting the syncSource attribute to ext_1pps_only the BTSE is synchronized to an external device which delivers 1pps pulses. There is no switching to a secondary synchronisation source if the 1pps signal fails. Configurable by LMT.

SYNCBTSE


GEMINI transport solutionsBTSplus sync by 1 pps

• Normally, the frequency stability at a BTS is ensured internally by the VCXO additionally stabilized by the Abis transport line (E1/T1), however, in some cases the achieved stability may be insufficient:

– Abis connected to the IP transport line

– Abis connected to a fixed network with poor clock quality

• The low frequency stability (10-6 – 10-5) of a BTS equipment can degrade the speech quality:– Slow down a HO phase causing ‘speech clipping’

– Reduce MOS (Mean Opinion Score) of on-going speech connections

• PPS (Pulse per Second) is an electrical signal very precisely indicating a beginning of a second:– Such signals are available in precise clocks including some GPS receivers

– When combined with another clock the achieved accuracy of the time source is up to few [nsec] (order of 10-9)

– The 3GPP recommended accuracy of the time source is Δt < 50×10-9 is maintained

• The frequency stability can be improved up to ~10-9 by the cheap 3rd party GPS equipment => the problems with speech quality are avoided


Gemini transport aspects RG20Evolution and scenarios


Evolution and scenariosRG10 (BSS) EP

BTSplus

TDMTDM

Dynamic Abis for BTSplus TDM transport

dedicated resources for TRX (TCH incl. PDCH@MCS1) and pool for EDGE (CS2-CS4, MCS2-MCS9)

LAPD multiplexing for TRXSIG and OMUSIG

FlexiBSC


BTSplus

BSS21157 Integrated IP card for BSC and TCSM

CESoPSN support with BTSplus integrated solution PSN transport

– BTSplus converts TDM signal to PW by CES-COBA (by itself)

– Ethernet connectivity provided by ETHCON

Cositing feature is not required

no features that require FlexiBTS support, only packet transport enabled

BTSplus must be equipped with CES-COBA and ETHCON

FlexiSM PWE

BTSplus withCES-COBA/ETHCON

PWE

PSNPSN

FlexiBSC FlexiBSCMultiBCF

BSS21443, Packet TRS for UltraSite/ BTSplus

Stand-alone System Module (ESMx) PSN transport

– TDM signal of BTSplus converted to PW by integrated FlexiBTS system module

– Ethernet connectivity via transport module of Flexi

stand-alone SM provides only media conversion => Cositing feature is not required

BTSplus with COBA2P8 or COBA4P12 (CES-COBA/ETHCON is not a must)

Evolution and scenariosRG20 : stand-alone BTSplus


Co-siting with FlexiBTS PSN transport

traffic handling:– TDM signal of BTSplus converted to PW by system

module of co-located FlexiBTS

– Ethernet connectivity via transport module of Flexi

FlexiBTS traffic handling:– transmitted using either its own PW or Packet Abis

over Ethernet

– up to 8 PWs can be transmitted by a single PW tunnel; Packet Abis over Ethernet and PWE can be supported in parallel

BSS21443 Packet TRS for UltraSite/ BTSplus

co-siting with FlexiBTS offers media conversion as well as features that require FlexiBTS support

BTSplus with COBA2P8 or COBA4P12 (CES-COBA/ETHCON is not a must)

PWE Ethernet aggregation PSN transport (for both BTSplus and FlexiBTS)

BTSplus traffic handling:–BTSplus converts TDM signal to PW by CES-COBA (i.e. by itself)

and is connected via „short-haul” cable to Ethernet Switch integrated with co-located FlexiBTS

–integrated Ethernet Switch forwards BTSplus PW to FlexiBSC

FlexiBTS traffic handling:–transmitted using either its own PW or Packet Abis over Ethernet

–up to 8 PWs can be transmitted by a single PW tunnel; Packet Abis over Ethernet and PWE can be supported in parallel

BSS21443 Packet TRS for UltraSite/ BTSplusand BSS21290 Flexi Ethernet Switching are required

co-siting with FlexiBTS offers media conversion as well as features that require FlexiBTS support

BTSplus must be equipped with CES-COBA and ETHCON

BTSplus

PWEPSN

FlexiBSCFlexiBTS

MultiBCFBTSplus with

CES-COBA/ETHCON

PWE

PSN

FlexiBSC

FlexiBTS withintegrated Ethernet switch

MultiBCF

Evolution and scenariosBTSplus co-siting with Flexi EDGE BTS (RG20)

29 © Nokia Siemens Networks RN22012EN20GLA1This configuration is possible but it does not enabled Packet transport!

Transport aspectsPacket transport for installed base in RG20: FlexiBTS co-siting

See below for overview on supported scenarios and meaning of particular connection types:

UltraSite BTSplus

TDM XC TDM PWE

TDM XC(COBA)

TDM PWE

(COBA)

PWE Eth agg.(CES-COBA)

Legacy Abis over TDM(Dynamic Abis)

Legacy Abis over Ethernet(CESoPSN)

Packet Abis over TDM

Packet Abis over Ethernet

FlexiBTSconnectionoptions

legacy BTSconnection

options

TDM XC

legacy BTS is connected to Flexi by means of Dynamic Abis while…

…FlexiBTS does TDM grooming towards BSC and cross-connects traffic towards legacy BTS

Packet Abis over TDM and Dynamic Abis can be transmitted in the same E1/T1 line (fractional TDM supported)

number of E1/T1 per FlexiBTS determines TRX configurations of co-sited base stations

TDM XC TDM XC

legacy BTS is connected to Flexi by means of Dynamic Abis while…

…FlexiBTS converts TDM stream to PW and transmits it towards BSC and cross-connects reconstructed (TDM) traffic towards legacy BTS

Packet Abis over Ethernet and PWE can be supported in parallel

FlexiBTS has one PWE tunnel, inside tunnel we might have up to 8 PWs, each PW can be either terminated in FlexiBTS or cross-connected towards legacy BTS

see next slide for stand-alone ESMx

TDM PWE TDM XC

BTSplus (equipped with CES-COBA and ETHCON) is connected to Flexi by means of CESoPSN (using integrated Ethernet Switching functionality) while…

…FlexiBTS transmits PW towards BSC and cross-connects PW towards its integrated Ethernet Switch which forwards PW to BTSplus

in addition to TDMPWE scenario this requires Ethernet Switching for FlexiEDGE BTS (BSS21290)

PWE Ethernet aggregation

Flexi BTS connection(common transport)

SEG1BTS1BTS4

SEG2BTS2BTS5

SEG3BTS3BTS6

BSC

legacy BTS

Flexi BTS

BTS1BTS2BTS3

BTS4BTS5BTS6

legacy BTS connection

SYNCMulti BCF(in co-siting

scenario)

gemini abis and transport solutions v1 8 ppt

Documents

bss abis

dynamic abis gemini

overview abis

dynamic abis concept

configuration of abis

dynamic abis principles

lapdmux dynamic abis

btsplus abis adaptation