fundamentals of sdh

Fundamentals of SDH

Training manual

8AS 90200 0551 VH ZZA Ed. 01

Edition 2002

© All rights reserved. Passing on and copying of this document, use and communication of its contents not

permitted without written authorization from Alcatel

© Alcatel University - 8AS 90200 0551 VH ZZA Ed.01 Page 0.2

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Note : Please print this document with comments pages


1 Introduction to the synchronous system1.1Transmission networks

1.2 Plesiochronous hierarchy

1.3 Synchronous hierarchy

1.4 SDH transport network

2 Base frame components2.1Container : Cn

2.2 Virtual container : VCn

2.3 Tributary Unit (Group) : TU (TUG)

2.4 Administrative Unit (Group) : AU (AUG)

2.5 ITU-T Multiplexing Structure

2.6 ETSI Multiplexing Structure

2.7 Base Frame : STM-1

2.8 Base elements : Overview

3 Section Overhead3.1Definition of Path and Section

3.2 Example of Path and section

3.3 STM-1 Section Overhead : SOH

3.4 STM-1 Regeneration Section Overhead : RSOH

3.5 STM-1 Multiplexing Section Overhead : MSOH

4 Pointer4.1 AU-4 Pointer addressing area

4.2 Au- Pointer management

4.3 AU-4 Pointer settings

4.4 AU-4 Pointer and justification use

4.5 Pointer justifications depending on clock deviation

Contents


5 Path Overhead, Low rate Multiplexing Mapping5.1 VC-4, VC-3 POH

5.2 140 Mbit/s mapping

5.3 VC3->TUG3->VC-4 Generation

5.4 STM-1 made up of 3 x VC-3

5.5 VC-2, VC-12, VC-11, POH

5.6 Asynchronous mapping at 2 Mbit/s

5.7 Generation of a VC-12 Multiframe

5.8 Organisation of the STM-1 made up of VC-12

5.9 TU-12 Unit Numbering in a VC-4

5.10 ATM cell insertion into a VC-4

6 High-Rate Multiplexing6.1 Byte interleaved Multiplexing

6.2 STM-N Section Overhead

6.3 Contiguous Concatenation

7 Usage of SDH Networks7.1 Example of SDH Network

7.2 Principle of Partitioning & Layering

7.3 Partitioning of Layer Networks & Sub-Networks

7.4 SDH Layer Networks

7.5 Example : Layers used by a Low Order Path

7.6 Definition of reference Points

7.7 Relation between Reference Points & Transport Entities

8 The Functional Model8.1 Layer function : Adaptation

8.2 Layer Function : Termination

8.3 Layer Function : Connection

8.4 Atomic & Basic Functions in a Network Element

Contents


9 Alarm and Error Handling9.1 Communication Alarms

9.2 Alarm Indication Signal : AIS

9.3 Remote Defect Indication : RDI

9.4 Alarm and Error Processing within an NE

9.5 Explanation of Alarm and Error Codes

9.6 Alarm and Error Processing

9.7 Performance Monitoring : PM

9.8 Tandem Connections

10 Protection and Restoration10.1 Equipment Protection : EPS

10.2 Network Protection

10.3 Network Restoration

11 Network Synchronisation11.1 Synchronisation Distribution

11.2 Clocks Types and Distribution in the Network

11.3 Synchronisation Diagram

11.4 Synchronous Equipment Timing

11.5 Synchronisation Signals : Quality and Priority

11.6 Linear Networks without SSM

11.7 Linear Network with SSM

12 Optical Interfaces12.1 Classification of Optical Interfaces

12.2 Laser Safety

12.3 Automatic laser Shutdown : ALS

12.4 Laser Operation Actions

13 Appendices

Contents


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Self assessment of the objectives

Instructional objectivesYes (orGlobally

yes)

No (orglobally

no)Comments

1. To be able to list the advantages of SDH

2. To be able to describe the SDH frame

3. To be to be able to describe the function of OHbytes

4. To be able to describe the function of thepointer

5. to be able to describe the multiplexing structurein an SDH frame

6. To be able to describe the multiplexing of STM-1 frames

7. To be able to describe the layering of SDHNetworks

8. To be able to describe the functional model inSDH

9. to be able to describe the way the alarms aremanaged in an SDH network

10. To be able to describe the different kinds ofprotection in SDH

11. To be able to describe the principles ofsynchronisation of SDH networks

12. To be able to list the optical interfaces used inSDH

Contract number :

Course title : Fundamentals of SDH

Client (Company, centre) :

Language : English dates from : to :

Number of trainees : Location :

Surname, First name :

Did you meet the following objectives ?Tick the corresponding box

Please, return this sheet to the trainer at the end of the training

��


Instructional objectivesYes (orGlobally

yes)

No (orglobally

no)Comments

Self assessment of the objectives (continued)

��

Thank you for your answers to this questionnaire

Other comments


© Alcatel University - 8AS 90200 0551 VT ZZA Ed.011.1

1 Introduction to the synchronous system


1.2

1 Introduction to the synchronous systemSession presentation

� Objective: to be able to list the advantages of SDH

� program:

� 1.1 Transmission networks

� 1.2 Plesiochronous hierarchy

� 1.3 Synchronous hierarchy

� 1.4 SDH transport network


1.3

1 Introduction to the Synchronous SystemTransmission networks

Switching system

exchange

NarrowbandBroadband

Switching system

exchange

NarrowbandBroadband

PDH / SDH

transport

network

OpticalMicrowave

Satellite

Intelligent network

Mobile communication network

Accesssystem

CopperOpticalRadio

Accesssystem

CopperOpticalRadio

Subscribersystem

VoiceData

Images

Management network

Subscribersystem

VoiceData

Images

� The "Transport" function comprises the transmission of traffic :� from one exchange to another� from one access system to another� directly between subscriber terminals


1.4

1 Introduction to the Synchronous SystemPlesiochronous Digital Hierarchy : PDH

32.064 97.728

44.7366.3121.544

8.4482.048 34.368 139.264 564.992

274.176

397.200

Frame structure not defined in the ITU-T Values in Mbit/s

G.753

G.752

G.751

G.752

G.755

G.751

G.757

G.742

G.752

*4*3

*5

*6

*4*4*4*4

*7*4

*3 *3

UNITEDSTATES

JAPAN

EUROPE

Interoperation(G.802)

� The Plesiochronous Digital Hierarchy (PDH):� is NOT designed for high rates� is based on three different standards� does not provide optical interconnections for interfaces supplied by different manufacturers� defines a cost intensive and fairly inflexible multiplexing structure� has a low binary rate dedicated for monitoring and a limited transmission quality� does not provide centralized network management� has an exclusively point-to-point connection topology

� The PDH standards were approved by the ITU-T in 1988 (G.702)


1.5

1 Introduction to the Synchronous SystemSynchronous Digital Hierarchy : SDH

� The SDH results from the SONET concepts proposed in the USA.

� The first SDH standards were approved by the ITU-T in 11/1988(recommendation series G.7xx):They define the rate, the frame and the multiplexing processes.

� The SDH is an international, high-rate telecommunication networks standard.

� The SDH is defined as an assembly of normalized digital transport structures.

� The SDH provides centralized network management.


1.6

1 Introduction to the Synchronous SystemSDH transport network

SDH Network

PlesiochronousSignals

ATM

PlesiochronousSignals

ATM


1.7

Thank you for answeringthe self-assessment

of the objectives sheet

1 Introduction to the Synchronous SystemEvaluation

� Objective: to be able to list the advantages of SDH



2 Base frame components


2.2

2 Base Frame ComponentsSession presentation

� Objective: to be able to describe the SDH frame

� program:

� 2.1 Container : Cn

� 2.2 Virtual container : VCn

� 2.3 Tributary Unit (Group) : TU (TUG)

� 2.4 Administrative Unit (Group) : AU (AUG)

� 2.5 ITU-T Multiplexing Structure

� 2.6 ETSI Multiplexing Structure

� 2.7 Base Frame : STM-1

� 2.8 Base elements : Overview


2.3

2 Base Frame ComponentsContainer : Cn

C-n

44.736 Mbit/s

n = 3

n = 3

34.368 Mbit/s

n = 2

6.312 Mbit/s

n = 12

2.048 Mbit/s

n = 111.544 Mbit/s

n = 4

139.264 Mbit/s

� C-n: Container, n = index of the container (n = 11, 12, 2, 3, 4)� The rate of a container depends on the signal which is being transported.� The mapping of a signal in the corresponding container is specified in G.707


2.4

2 Base Frame ComponentsContainer : VCn

C-4

C-3

C-2

C-12

C-11

139.264 Mbit/s

44.736 Mbit/s34.368 Mbit/s

6.312 Mbit/s

2.048 Mbit/s

1.544 Mbit/s

VC-4POH

VC-2

VC-12

VC-11

VC-3

POH

POH

POH

POH

POH

C-n

VC-n

� VC-n: Virtual Container, it is made up of a C-n and a POH� POH: Path OverHead� The POH is an additional transport-capacity designed for the container:

it carries details on e.g. the payload contents.� VC-n = C-n + POH n = 11, 12, 2, 3, 4


2.5

2 Base Frame ComponentsTU

C-4

C-3

C-2

C-12

C-11

139.264 Mbit/s

44.736 Mbit/s34.368 Mbit/s

6.312 Mbit/s

2.048 Mbit/s

1.544 Mbit/s

VC-4POH

VC-2

VC-12

VC-11

VC-3POH

POH

POH

POH

TU-11

TU-12

TU-2

TU-3

high order low order

� TU: Tributary Unit, it is made up of a low order VC-n (n=11,12, 2, 3) and a pointer� The pointer is an additional rate used to locate its VC-n within the TU: Pointers allow to transport virtual containers phase shifted

related to their TU, which facilitates data processing in the network element.� For high order container (VC-3, VC-4) see: Administrative Unit (AU)� TU-n = VC-n + PTR n = 11, 12, 2, 3


2.6

2 Base Frame ComponentsTUG

TU-12

C-4

C-3

C-2

C-12

C-11

139.264 Mbit/s

44.736 Mbit/s34.368 Mbit/s

6.312 Mbit/s

2.048 Mbit/s

1.544 Mbit/s

VC-4POH

VC-2

VC-12

VC-11

VC-3POH

POH

POH

POH

TU-3

TU-11

TUG-3

TUG-2 TU-2

X1

X3

X7

X1

X3

X4


� TUG: Tributary Unit Group, the TUG-2 / TUG-3 can consist of several types of capacity payloads with different sizes.� The TUG-2 is 4 X TU-11 or

3 X TU-12 or1 X TU-2.

� The TUG-3 is 7 X TUG-2 or1 X TU-3.

� The TUG is obtained through byte interleaved multiplexing.� For high order container (VC-3, VC-4) see: Administrative Unit Group (AUG)� TUG-k = m * TU-n n = 11, 12, 2, 3


2.7

2 Base Frame ComponentsAUG

TU-12

C-4

C-3

C-2

C-12

C-11

139.264 Mbit/s

44.736 Mbit/s34.368 Mbit/s

6.312 Mbit/s

2.048 Mbit/s

1.544 Mbit/s

VC-2

VC-12

VC-11

VC-3POH

POH

POH

POH

TU-3

TU-11

TUG-3

TUG-2 TU-2

X1X3

X7

X1

X3

X4

VC-3POH

X7

AU-4

AU-3

VC-4POH


X3

X1

AUG

� AU: Administrative Unit, it is made up of a high order VC-n (n = 3,4) and a pointer.� The AU-3 multiplexing structure is designed for compatibility with SONET frames.� Two types of virtual containers VC-n are used:

� Lower order VC-n (n = 11,12, 2, 3)This entity contains a single container n associated with the POH.

� Higher order VC-n (n = 3, 4)This entity contains either a single container n or a TUG (Tributary Unit Group) assembly (TUG-2 or TUG-3) associated with the POH.

� VC-3 can be: lower order � TU-3 � TUG-3 � VC-4 � AU-4 orhigher order � AU-3

AU-n = VC-n + PTR n = 3, 4

AUG = 1 * AU-4 or 3 * AU-3


2.8

2 Base Frame ComponentsITU-T Multiplexing Structure

TU-12

C-4

C-3

C-2

C-12

C-11

139.264 Mbit/s

44.736 Mbit/s34.368 Mbit/s

6.312 Mbit/s

2.048 Mbit/s

1.544 Mbit/s

VC-2

VC-12

VC-11

VC-3POH

POH

POH

POH

TU-3

TU-11

TUG-3

TUG-2 TU-2

X1

X7

X1

X3

X4

X7

STM-N

STM-0

AU-4

AU-3

X3

VC-4POH

VC-3POH

High ratemultiplexing

Insertion of the SOH

AUG

X3

Low ratemultiplexing

X1

X1

* N

� N = 1, 4, 16, 64� STM: Synchronous Transport Module� ITU-T: International Telecommunication Union – Telecommunication sector� SDH-SONET compatibility: see Appendix A2


2.9

2 Base Frame ComponentsETSI Multiplexing Structure

TU-12

C-4

C-3

C-12

C-11

139.264 Mbit/s

44.736 Mbit/s34.368 Mbit/s

2.048 Mbit/s

1.544 Mbit/s

VC-2

VC-12

VC-11

VC-3POH

POH

POH

POH

TUG-3

TUG-2 TU-2

X1

X7

X1

X3

STM-N AU-4

X3

VC-4POH

Insertion of the SOH

AUG* N

TU-3

X1

� N = 1, 4, 16, 64� ETSI: European Telecommunication Standard Institute.

� It is a subset of ITU-T standard.� It focuses on European digital signals to simplify equipment.� ETSI-standard will be handled in the following chapters

� In the SDH signal (or data) processing takes place in three levels:� mapping of digital signal to container C-n� multiplexing of low order containers to high order containers via TUGs and finally via AU (AUG) into the STM-1 base

frame.� multiplexing of base frame, i. e. STM-1 frames at 155.520 Mbit/s with each other to create a high-rate frame:

� STM-4 at 622.080 Mbit/s� STM-16 at 2488.320 Mbit/s� STM-64 at 9953.280 Mbit/s


2.10

2 Base Frame ComponentsBase Frame STM-1

MSOH

RSOH

AU-4 pointerPOH

C-4

270

2430

1

VC-4

270 columns (bytes)

9

9 rows(bytes)

MSOH + RSOH= SOH

1

� The STM-1 base frame is structured with the following characteristics:� Length : 2430 bytes� Duration : 125 µs i.e. 8000 frames/s� Rate : 155.520 Mbit/s� Payload : 2340 bytes i. e. 149.760 Mbit/s

1byte i.e. 64 kbit/s (e.g. speech channel)� STM Synchronous Transport Module

MSOH Multiplex Section OverheadRSOH Regenerator Section OverheadSOH Section Overhead

� STM-1 = AU-4 + SOH


2.11

2 Base Frame ComponentsBase Elements : Overview

Container C-n n = 11, 12, 2, 3, 4

Virtual Container VC-n = C-n + POH n = 11, 12, 2, 3, 4

Tributary Unit TU-n = VC-n + PTR n = 11, 12, 2, 3

Tributary Unit Group TUG-k = m * TU-n k = 2, 3

m = 4, 3, 1, 7n = 11, 12, 2, 3

Administrative Unit AU-n = VC-n + PTR n = 3, 4

Administrative Unit Group AUG = 1 * AU-4 or 3 * AU-3

Synchronous Transport Module STM-1 = AU-4 + SOH (Base Frame)STM-N = 4 * STM-m N = 4, 16, 64

m = 1, 4, 16

� In the SDH signal (or data) processing takes place in three levels:� mapping of digital signal to container C-n� multiplexing of low order containers to high order containers via TUGs and finally via AU (AUG) into the STM-1 base

frame� multiplexing of base frame, i. e. STM-1 frames at 155.520 Mbit/s with each other to create a high-rate frame:

� STM-4 at 622.080 Mbit/s� STM-16 at 2488.320 Mbit/s� STM-64 at 9953.280 Mbit/s


2.12



2 Base Frame Components Evaluation

� Objective: to be able to describe the SDH frame



3 Section Overhead


3.2

3 Section OverheadSession presentation

� Objective: to be able to describe the function of OH bytes

� program:

� 3.1 Definition of Path and Section

� 3.2 Example of Path and section

� 3.3 STM-1 Section Overhead : SOH

� 3.4 STM-1 Regeneration Section Overhead : RSOH

� 3.5 STM-1 Multiplexing Section Overhead : MSOH


3.3

3 Section OverheadDefinition of Path and Section

STM-N

SOH

VCC

C

POH

Terminal- or Cross-Connect-Multiplexer

STM-N

SOH

VC C

C

POH

Multiplex Section

Path

Regenerator

ples

ioch

rono

usS

igna

l

ples

ioch

rono

usS

igna

l

Terminal- or Cross-Connect-Multiplexer

Regenerator

RegeneratorSection

RegeneratorSection

RegeneratorSection

STM-N STM-N

VC VC

� C Container� VC Virtual Containe� POH Path Overhead� SOH Section Overhead

� The SECTION is the link between two network elements.

� The PATH connects the two points where the POH is generated / analyzed.


3.4

3 Section OverheadExample of Path and Section

Section 2

SDH NetworkSecti

on 1

Path 1STM-1

STM-1

Path 2

STM-16

STM-4STM-4

STM-4

2 Mbit/s 2 Mbit/s2 Mbit/s

2 Mbit/s

NE-A

NE-CNE-B

NE-D

NE-E NE-F

� NE Network Element

� Overheads carrying specific info of every path or section, from one end to the other (e.g. Path 1 between NE-A and NE-E)


3.5

3 Section OverheadSection Overhead : SOH

Bytes reserved for national use.

RSOH

MSOH

Unscrambled bytes. Their contents should therefore be monitored.

Bytes depending on the medium (satellite, radio relay system, ...)

*A1

*A1

*A1

*A2

*A2

*A2

*J0

* *

B1 D D E1 D F1

D1 D D D2 D D3

AU-4 pointer

B2 B2 B2 K1 K2

D4 D5 D6

D7 D8 D9

D10 D11 D12

S1 Z1 Z1 Z2 Z2 M1 E2

9 ro

ws

9 bytes

*

∆∆∆∆

� All unmarked bytes are reserved for future international normalization (medium dependence, additional national use and other purposes).

� The Section OverHead (SOH) is divided into two subassemblies: � RSOH: Regenerator Section OverHead� MSOH: Multiplex Section OverHead


3.6

3 Section OverheadRegeneration Section Overhead : RSOH

RSOH: Regenerator Section OverHead

*A1

*A1

*A1

*A2

*A2

*A2

*J0

* *

B1 D D E1 D F1

D1 D D D2 D D3

� A1, A2 The Frame Alignment Word is used to recognize the beginning of an STM-N frame.A1: 1111 0110 = F6 (HEX)

A2: 0010 1000 = 28 (HEX)

� J0 Path Trace. It is used to give a path through an SDH Network a ‘Name’. This message (Name) enables the receiver to check the continuity of its connection with the desired transmitter.

� B1 Bit Error Monitoring. The B1 Byte contains the result of the parity check of the previous STM frame, before scrambling of the actual STM frame. This check is carried out with a Bit Interleaved Parity check (BIP-8).

� E1 Engineering Orderwire (EOW). It can be used to transmit speech signals beyond a Regenerator Section for operating and maintenance purposes.

� F1 User Channel. It is used to transmit data and speech for service and maintenance.

� D1 - D3 Data Communication Channel at 192 kbit/s (DCCR).This channel is used to transmit management information via the STM-N frames


3.7

3 Section OverheadMultiplexing Section Overhead : MSOH

B2 B2 B2 K1 K2

D4 D5 D6

D7 D8 D9

D10 D11 D12

S1 Z1 Z1 Z2 Z2 M1 E2

MSOH: MultiplexSection OverHead

� B2 : Bit Error Monitoring. The B2 Bytes contains the result of the parity check of the previous STM frame, except the RSOH, before scrambling of the actual STM frame. This check is carried out with a Bit Interleaved Parity check (BIP24).

� K1, K2 Automatic Protection Switching (APS). In case of a failure, the STM frames can be routed new with the help of the K1, K2 Bytes through the SDH Network. Assigned to the multiplexing section protection (MSP) protocol.

� K2 (Bit6,7,8) MS_RDI: Multiplex Section Remote Defect Indication (former MS_FERF: Multiplex Section Far End Receive Failure).

� D4 to D12 Data Communication Channel at 576 kbit/s (DCCM). (See also D1-D3 in RSOH)

� S1 (Bit 5 - 8) Synchronization quality level0000 Quality unknown0010 G.811 10-11/day frequency drift 0100 G.812T transit 10-9 /day frequency drift 1000 G.812L local 2*10-8/day frequency drift 1011 G.813 5*10-7/day frequency drift1111 Not to be used for synchronization

� E2 Engineering Orderwire (EOW). Same function as E1 in RSOH.

� M1 MS_REI: Multiplex Section Remote Error Indicator, number of interleaved bits which have been detected to be erroneous in the received B2 bytes. (former MS_FEBE: Multiplexing Section Far End Block Errored)

� Z1, Z2 Spare bytes


3.8



3 Section Overhead Evaluation

� Objective: to be able to describe the function of OH bytes



4 Pointer


4.2

4 PointerSession presentation

� Objective: to be able to describe the function of the pointer

� program:

� 4.1 AU-4 Pointer addressing area

� 4.2 Au- Pointer management

� 4.3 AU-4 Pointer settings

� 4.4 AU-4 Pointer and justification use

� 4.5 Pointer justifications depending on clock deviation


4.3

4 PointerAU-4 Pointer addressing area

Pointer addressing area

AU-4 Pointer

Au-4 Pointer

VC-4


4.4

4 PointerAU-4 Pointer management

VC-4 VC-4 VC-4 VC-4

pointer generationpointer interpretation

retrieved clockextractionof the SOH

local clockof the NE

receivedSTM-1

transmittedSTM-1

insertionof the SOH

� The rate of a transmitted VC-4 is consistent with the rate of the received VC-4.

� Pointers allow to transport virtual containers phase shifted related to their TU respectively AU, which facilitates data processing in the network element.


4.5

4 PointerAU-4 Pointer settings

NE-B

Plesio.

Clock 1 Clock 2 Clock 3

STM-1 STM-1

Plesio. Plesio.

STM-1(Clock 4)

Pointer movement

NE-CNE-A

� Negative justification: Clock 1 > Clock 2 The rate of the incoming STM-1 is

higher than the capacity of the outgoing STM-1. Additional bits must be used to increase the capacity of the outgoing STM-1.

� Positive justification: Clock 1 < Clock 2 The rate of the incoming STM-1 is

lower than the capacity of the outgoing STM-1. Additional stuffing bits must be used in the outgoing STM-1 to reduce its useful capacity


4.6

4 PointerAU-4 Pointer and justification use

H3PTR(n)

H3PTR(n)

H3PTR(n+1)

H3PTR(n+1)

H3PTR(n)

H3PTR(n)

H3PTR(n-1)

H3PTR(n-1)

B

Frame N

Frame N + 1

Frame N + 2

Frame N + 3

Negative Justification Positive Justification

� PTR(n): Pointer with value n � H3: 3 stuffing bytes used for negative justification� B: 3 stuffing bytes used for positive justification

� Negative justification:If the frame rate of container VC-n is too fast compared to that of the AUG, the alignment of container VC-n must be periodically advanced in time and the pointer‘s value reduced by one unit.

� Positive justification:If the frame rate of container VC-n is too slow compared to that of the AUG, the alignment of container VC-n must be periodically delayed in time and the pointer‘s value increased by one unit.

� A positive or negative justification corresponds to a 3-byte offset in the AU-4.


4.7

4 PointerPointer and justification use (continuation)

H1 H1*

H1*

H2 H2**

H2**

H3 H3 H3 0 0 0 1 1 1 2 2 2

87

522

782

1

2

3

4

5

9

1 9 10 270

3 negative justificationopportunity bytes

3 positive justificationopportunity bytes

868686

� The value of the pointer remains constant for at least 3 consecutive frames (G.707).The maximum justification therefore takes place in 1 out of every 4 frames.

H1+H2: NNNNSSPP PPPPPPPPNNNN New data flag (4 bits)SS Type of pointer, Section Supporting Bits (2 bits):

10 for AU-4 / AU-3 pointer01 for TU-3 pointer 00 for concatenated payload

PPPPPPPPPP Pointer value (10 bits): every third byte in VC-4 must be addressable:

(261 * 9) byte / 3 = 783 addresses

H1*+H2**: 1001SS11 11111111 Concatenation Indication (CI):SS 00 SDH-SONET interworking

01 SDH


4.8

4 PointerPointer justifications depending on clock deviation

Nu

mb

ero

f p

oin

ter

just

ific

atio

n e

ven

ts/

seco

nd

2000

200

20

6.48 Hz2

0,2

0,02

3.10-9 3.10-8 3.10-7 3.10-6 3.10-5 3.10-4

1 ppm≈300 ppm

For

bidd

en a

rea

Difference of incoming clock to equipment

clock

� A 1-ppm clock difference causes a pointer action frequency of 6.48 Hz, one action every 1235 frames.

� Maximum clock difference: � One justification event every 4 frames (ITU-T)� 3 bytes / (2430 bytes x 4) ≈ 300 ppm


4.9



4 PointerEvaluation

� Objective: to be able to describe the function of the pointer



5 Path Overhead, Low rate Multiplexing Mapping


5.2

5 Path Overhead, Low Rate Multiplexing, MappingSession presentation

� Objective: to be able to describe the multiplexing structure in an SDH frame

� program: � 5.1 VC-4, VC-3 POH� 5.2 140 Mbit/s mapping� 5.3 VC3->TUG3->VC-4 Generation� 5.4 STM-1 made up of 3 x VC-3� 5.5 VC-2, VC-12, VC-11, POH� 5.6 Asynchronous mapping at 2 Mbit/s� 5.7 Generation of a VC-12 Multiframe� 5.8 Organisation of the STM-1 made up of VC-12� 5.9 TU-12 Unit Numbering in a VC-4� 5.10 ATM cell insertion into a VC-4


5.3

5 Path Overhead, Low Rate Multiplexing, MappingVC-4 , VC-3 POH

J1

B3

C2

G1

F2

H4

F3

K3

N1

C-4 or C-3

POH

VC-4 , VC-3 POH

� C2: Signal label - indicates the composition of C-4 / C-3

(HEX-values)00: path not equipped01: path equipped, payload not specific02: TUG payload structure (TUG-2/ TUG-3)03: TU alignment, locked TU mode04: asynchronous mapping of signals at 34 / 45 Mbit/s in a C-3 container12: asynchronous mapping of signals at 140 Mbit/s in a C-4 container13: ATM mapping14: MAN mapping (DQDB)15: FDDI mapping (100 Mbit/s, Fiber Distributed Data Int)FE: tests signal, 0.181 specific mapping FF: VC-AIS signal


5.4

5 Path Overhead, Low Rate Multiplexing, MappingVC-4, VC-3 POH (continuation)

1 2 3 4 5 6 7 8R E I R D I reserved spare

J1 Path trace, identifier of the pathIt is used to check that the path connection between transmitter andreceiver is maintained. 64-byte character string or one 16-byte frame,transmitted in 64 resp. 16 consecutive STM frames (64*125µs or 16*125µs)

B3 BIP-8, parity block check of the previous VC-4 / VC-3 before scrambling

C2 Signal Label

G1 Path status of the opposite path terminal

F2, F3 Path user channels: assigned to the user's communication requirements.

H4 Multiframe Indicator: used to designate a specific use of the VC-4's capacity: VC-2, VC-12, VC-11

K3 Automatic Protection Switching (APS) channel (bits 1 to 4)

N1 Tandem connection monitoring (TCM) function (bits 1 to 4).Data link (bits 5 to 8).

J1

B3

C2

G1

F2

H4

F3

K3

N1

� G1, bit 1 to 4: HP_REI: Higher Path Remote Error Indication Return of the remote B3 (BIP-8 code) (former HP_FEBE: Far End Block Error)

� G1, bit 5: HP_RDI: Higher Path Remote Defect Indication Path remote alarm (former HP_FERF: Far End Receive Failure)

� G1, bit 6 to 7: reserved for optional use (transmission of remote alarm with fault differentiation).If they are not used, they shall be set to 00 or 11.

� G1, bit 8: reserved for future use.

� H4: A multiframe synchronization is required if the VC-4 contains VC-2s, VC-12s, VC-11s. These

multiframes are spread over 500 µs. It is therefore necessary to indicate in which VC-4 they start.


5.5

5 Path Overhead, Low Rate Multiplexing, Mapping140 Mbit/s Mapping

blocks 201

rows

1

9

C-4: 20 blocks of 13 bytes on 9 rows

180blocks

� Breakdown of C-4 into 180 blocks of 13 bytes ((9 * 20) * 13 = 2340 bytes payload)


5.6

5 Path Overhead, Low Rate Multiplexing, Mapping140 Mbit/s Mapping (continuation)

Structure of one of the nine lines in container C-4

W 96 D X 96 D Y 96 D Y 96 D Y 96 D

X 96 D Y 96 D Y 96 D Y 96 D X 96 D

Y 96 D Y 96 D Y 96 D X 96 D Y 96 D

Y 96 D Y 96 D X 96 D Y 96 D Z 96 D

1 12 bytes

W

X

DDDDDDDD

CRRRRROO

Y

Z

RRRRRRRR

DDDDDDSR

D Data bitR Fixed stuff bitO Overhead bitS Justification opportunity bitC Justification control bit

� The overhead bits (O) are reserved for future communication requirements

� CCCCC = 00000 means that bit S (in byte Z) is a data bit.� CCCCC = 11111 means that bit S (in byte Z) is a justification bit.

� Majority vote for protection against decision errors (data or justification bit).


5.7

5 Path Overhead, Low Rate Multiplexing, MappingVC-3 --> TUG-3 --> VC-4 Generation

J1B3C2G1F2H4F3K3N1

POH VC-3

1 85

125 µsperiodicity

1

9

rows

VC-3: 85 columns of bytes

TUG-3 A TUG-3 B TUG-3 C

POH

VC-4

A B C A C A B C

1 4 5 6 261

1 86 1 86 1 86

123

PTRA

PTRB

PTRC

stuffing

2 3

...9

� A VC-3 POH has the same structure as the VC-4 POH.

� The TU-3 pointer is similar to the AU-4 pointer and serves the same purpose.

� The TUG-3 defines the locations of the TU-3s in the VC-4.

� Bytes H1 H2 H3 of the TU-3 pointers are the bytes of rows 1, 2 and 3 of columns 4, 5 and 6 of the VC-4.


5.8

5 Path Overhead, Low Rate Multiplexing, MappingSTM-1 made up of 3 x VC-3

AU-4 pointer

AU-4 pointer

J1B3C2G1F2H4F3K3N1

J1B3C2G1F2

N1K3F3H4

F2

G1

764 764 764

84 84 84

764 764 764

84 84 84

H1 H1 H1 595 595 595

H2 H2 H2H3 H3 H3

85 85 85 86

0 0 0 1 82 83 83 83

82 83 83 83

H1 H1 H1 595 595 595

H2 H2 H2H3 H3 H3

85 85 85 86

0 0 0 1

MSOH

RSOH

MSOH

MSOH

RSOH

1 9 10

680 680 680

VC

-3#A

VC

-3#B

VC

-3#C

680 680 680

A B C A B C A B C A C A B C

POH VC-4

261 columns of bytes

270

Stuffing

� Payload: 2340 bytes = 3 * 9 * 85 bytes (3 * VC-3: A, B, C)+3 * 3 bytes (3 * Pointer)+3 *12 bytes (3 * stuffing)


5.9

5 Path Overhead, Low Rate Multiplexing, MappingVC-2, VC-12, VC-11 POH

BIP-2 REI RFI Signal label RDI1 2 3 4 5 6 7 8

Path trace (16-byte frame)

Network operator byte (Monitoring function)

Automatic Protection Switching (APS) channel (bits 1 to 4).

V5

J2

N2

K4

� V5: BIP-2 even parity of order 2 of the previous VC-2 / VC-12 / VC-11REI LP_REI: Lower Path Remote Error Indication

Set to 1 and returned to the source of the path if the BIP-2 parity detects one or more errorsRFI Remote Failure Indication in the path (optional)

A failure is a fault which lasts longer than the maximum duration of the transmission systems protection mechanisms.

Signal label (bit 5, 6, 7) indicates the composition of C-2 / C-12 / C-11:

0 0 0 not equipped or monitoring not equipped0 0 1 equipped - not specific0 1 0 asynchronous0 1 1 bit synchronous (not used)1 0 0 byte synchronous1 0 1 reserved for future use1 1 0 test signal, 0.181 specific mapping1 1 1 VC-AIS signal

RDI LP_RDI: Lower Path Remote Defect Indication Indicates connection and server faults


5.10

5 Path Overhead, Low Rate Multiplexing, MappingAsynchronous Mapping at 2 Mbit/s

V5R R R R R R R R

32 bytes

R R R R R R R RJ2

C1 C2 O O O O R R

32 bytes

R R R R R R R RN2

C1 C2 O O O O R R

32 bytes

R R R R R R R RK4

C1 C2 R R R R R S1S2 D D D D D D D

31 bytes

R R R R R R R R

D data bitR fixed stuff bitO overhead bitS justification opportunity bitC justification control bit

140bytes

VC-12 Multiframe(= 4 * VC-12)

� The 2 Mbit/s signal is placed in a C-12 without taking ist composition into consideration: No link between the 2 Mbit/s frame and the C-12.

� Justification process upon mapping within the C-12 to enable a +/- 50 ppm synchronization tolerance.

� Bits are placed in the C-12 as they arrive.

� VC-12s (35 bytes in 125 µs) of 4 consecutive STM-1 frames (4 x 125 µs = 500 µs) are combined to a multiframe (140 bytes in 500 µs) to reduce overhead / useful signal ratio.


5.11

5 Path Overhead, Low Rate Multiplexing, MappingGeneration of a VC-12 Multiframe

V1

V5

V2

V3

V4

J2

N2

K4

125 µs

250 µs

375 µs

500 µs

XXXXXX00

XXXXXX01

XXXXXX10

XXXXXX11

TU-12 VC-12byte H4 status

35 bytes

35 bytes

35 bytes

35 bytes

140 bytescapacity of 4 container VC-12: multiframe (bytes/500 µs)

0 µs

VC-12 Multiframe= 4 * VC-12

� TU-n pointer: 4 bytes V1, V2, V3, V4� V1, V2: pointer value� V3: negative justification opportunity� V4: spare

� H4: multiframe indicator - used for location within the 500 µs multiframe (see VC-4 POH)

� Different sizes of virtual containers VC:� VC-11 26 bytes� VC-12 35 bytes� VC-2 107 bytes


5.12

5 Path Overhead, Low Rate Multiplexing, MappingOrganization of the STM-1 made up of VC-12

N1

B3

J1

MSOH

AU-4 pointer

RSOH

1 10 19 82 145 208 270

Multiframe No 1

Multiframe No 2

Multiframe No 3J1

N1

NPI

NPI

NPI

1 2 3 63

1 2 3 63

Stuffing

125 µs

250 µs

C2

G1

F2

H4

F3

K3

1 2 3 1 2 3 1 2 363 63 63

� NPI: Null Pointer Indication(bytes used for STM-1 made up of 3 VC-3s via TUG-3)

� VC-12 TU-12 TUG-2 TUG-3 VC-4 AU-4


5.13

5 Path Overhead, Low Rate Multiplexing, MappingTU-12 Unit Numbering in a VC-4

VC4POH

1

111

2

211

3

311

4

121

5

221

6

321

7

131

8

231

9

331

10

141

11

241

12

341

13

151

14

251

15

351

16

161

17

261

18

361

19

171

20

271

21

371

22

112

23

212

24

312

60

363

61

173

62

273

63

373

1

11

1

58

163

59

263

60

363

61

173

62

273

63

373

1 32

54 6

78

910

1112

1314

1516

1718

1920

2122

2324

2526

2728

2930

3132

33 6970

7172

73256 258 260 Number of VC-4

container column x

Time period number

KLM

address

TUG-2 #

VC-12 #

x7

TUG-3 # 3 3 3 3 3 3 3 33 3 3 3 3 3 3 3 33 3 3 3

TUG-3 # 2 2 2 2 2 2 2 22 2 2 2 2 2 2 2 22 2 2 2TUG-3 # 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 11 1 1 1

737

373

63

53

43

33

23

13

72

62

52

42

32

22

12

71

61

51

41

31

21

11

TUG-2 #VC-12 #

x3

63

62

61

53

52

51

43

42

41

33

32

31

23

22

21

13

12

11

73

72

71

0 0 0 0 0 0 0 0 0 0

......

257 259... ...

� Each TU-12 unit has an address (K, L, M), whereK = TUG-3 number (1 to 3)L = TUG-2 number (1 to 7)M = TU-12 number (1 to 3)

� VC-12 TU-12 TUG-2 TUG-3 VC-4 AU-4


5.14

5 Path Overhead, Low Rate Multiplexing, MappingATM Cell Insertion into VC-4

Header Payload

5 48

J1

B3

C2

G1

F2

H4

F3

K3

N1

� ATM: Asynchronous Transfer Mode

� ATM cell is a 53 byte indivisible cell

� The cell train is mapped in the containers in accordance with the byte structure

� ATM cells may overlap a VC-4 container frame boarder

� Number of cells inside C-4:2340 bytes / 53 bytes = 44 ATM-cells and 8 bytes remainder

� Mapping of ATM cells in containers: VC-4-Xc, VC-2-mc, VC-4, VC-3, VC-2, VC-12, VC-11 (G.707, I.432)

� VC-4-Xc virtual container obtained through the Contiguous Concatenation of X containers C-4.

� VC-2-mc virtual container obtained through the Contiguous Concatenation of m containers C-2.


5.15



5 Path Overhead, Low Rate Multiplexing, Mapping Evaluation

� Objective: to be able to describe the multiplexing structure in an SDH frame



6 High-Rate Multiplexing


6.2

6 High Rate MultiplexingSession presentation

� Objective: to be able to describe the multiplexing of STM-1 frames

� program:

� 6.1 Byte interleaved Multiplexing

� 6.2 STM-N Section Overhead

� 6.3 Contiguous Concatenation


6.3

6 High Rate MultiplexingHigh-Rate Multiplexing

RSOH

AU-PTR

MSOH

PAYLOAD

9 x N

270 x N

261 x N

125 µsperiodicity9

� A STM-N frame is made up of N * 270 columns of 9 lines each.

� N = 1, 4, 16, 64

� STM-1 at 155.520 Mbit/sSTM-4 at 622.080 Mbit/sSTM-16 at 2.488.320 Mbit/sSTM-64 at 9.953.280 Mbit/s


6.4

6 High Rate MultiplexingByte interleaved multiplexing

MU

LT

IPL

EX

ING

(byt

e in

terl

eavi

ng

)VC-4VC-4

PTR

AU-4

#N

VC-4VC-4

PTR

AU-4

#3

VC-4VC-4

PTR

AU-4

#2

VC-4VC-4

PTR

AU-4

#1

RSOH

MSOH

Addition of the STM-N RSOH

Addition of the STM-N MSOH

N x 9

N x 9

N x 9 N x 261

3

5

STM-N

#3

#N

#1

#2


6.5

6 High Rate MultiplexingSTM-N Section Overhead

Bytes reserved for national use.

Unscrambled bytes. Their contents should therefore be monitored.*

NOTE: All unmarked bytes are reserved for future international normalization (medium dependent, additional national use and other purposes).

B2 K1 K2

D4 D5 D6

D7 D8 D9

D10

D11

D12

S1 E2

*A1

*A1

*A2

*A2

B2 B2

N * 9 bytes

9 ro

ws

RS

OH

MS

OH

*A1

B1 E1 F1

D1 D2 D3

*A2

*J0

*A1

B2 B2 B2

M1position (9, 4, 3)max (9, 9,16)

*A1

*A1

*A2

*A2

*A2

*Z0

N * AU-4 pointers

N

row, block, byte

* * **

� N = 1, 4, 16, 64

� All OH-Bytes are related to section.Most of them therefore exists only once.

Exception: - A1, A2 to keep accuracy of frame detection- B2 to keep accuracy of block check for the increased block size

� Z0: reserved for future international normalization;to be used in the event of interoperation with a remote equipment using the module identifier function STM (C1) and with the equipment using the regeneration section trace function.


6.6

6 High Rate MultiplexingContiguous Concatenation

RSOH

4 * AU-PTR

MSOH

9 x 4 = 36

270 x 4 = 1080

261 x 4 = 1044

STM-4

9

Payload VC-4-4c

VC-4 POH

J1

N1

stuffing

� Contiguous Concatenation is a procedure associating several virtual containers, which allows their combined capacity to be used as a single container.

� Contiguous Concatenation is defined for TU-2 and AU-4 (SONET: also for AU-3)

� This technique has the advantage of optimizing the frame filling relative to the mapping of a higher rate container.

� STM-4 / STM-16 is used to transport a VC-4-Xc signal (SONET: STM-1 for VC-3-3c)

� Application: � for bit streams which can not be contained in a VC-4� typical: ATM signals with a bandwidth of 600 Mbit/s

� Procedure:� the first AU-pointer indicates the J1-byte (POH VC-4), the other 3 pointers indicate Concatenation Indication (CI): three

columns with stuffing bytes � H1*+H2**: 1001SS11 11111111 Concatenation Indication (CI):

SS: 00 SDH-SONET inter-working01 SDH


6.7



6 High Rate MultiplexingEvaluation

� Objective: to be able to describe the multiplexing of STM-1 frames



7 Usage of SDH Networks


7.2

7 Usage of SDH NetworksSession presentation

� Objective: to be able to describe the layering of SDH Networks

� program:

� 7.1 Example of SDH Network

� 7.2 Principle of Partitioning & Layering

� 7.3 Partitioning of Layer Networks & Sub-Networks

� 7.4 SDH Layer Networks

� 7.5 Example : Layers used by a Low Order Path

� 7.6 Definition of reference Points

� 7.7 Relation between Reference Points & Transport Entities


7.3

7 Usage of SDH NetworksExample SDH Network

SDH-Network

ATM-Equipment

34 Mbit/s

STM-4

STM-1

6

STM

-4 STM-4

STM-1

STM-1

STM-1

6STM-16

STM-16

45 Mbit/s

ATM VP

ATM Equipment

PDH Equipment

ATM VP

2 Mbit/s

140 Mbit/s

PDH EquipmentPDH Equipment

PDH Equipment

ST

M-4

STM-4

� SDH networks are used to transport� PDH signals� ATM signals

� ATM VP: Virtual Path of the Asynchronous Transfer Mode

� An SDH network can be seen as a set of different network layers (path layers, section layers, physical layers) and can also be divided into different sub-networks.


7.4

7 Usage of SDH NetworksPrinciples of Partitioning and Layering

Sub-networks Links

Sectionlayer network

Pathlayer network

Physicallayer network

Layering view(client/server association)

Layering concept

Partitioning view

Partitioning conceptOrthogonal views of layering and partitioning

� Application of the partitioning concept

The partitioning concept is important as a framework for defining:� the network structure within a layer network� administrative boundaries between network operators jointly providing connections within a single layer network� domain boundaries within a layer network of a single operator to allow the apportioning of performance objectives to the

architectural components� routing domain boundaries within the layer network of a single operator� the part of a layer network or sub-network that is under the control of a third party for routing purposes (e. g. customer

network management)

� Application of the layering concept

The layering concept of the transport network allows:� each layer network to be described using similar functions� the independent design and operation of each layer network� each layer network to have its own operations, diagnostic and automatic failure recovery capability� the possibility of adding or modifying a layer network without affecting other layer networks from the architectural viewpoint� simple modeling of networks that contain multiple transport technologies


7.5

7 Usage of SDH NetworksPartitioning of layer networks and sub-networks

National part sub-network International part sub-network

Local part sub-network in anational part sub-network

Transit part sub-network in anational part sub-network

� Partitioning concept

In general a sub-network is constructed by representing the physical implementation as links and sub-networks, starting from the matrix that is the smallest (indivisible) sub-network. A set of sub-networks and links may be abstracted as a higher (containing) sub-network. The way in which the contained sub-networks are interconnected by links describes the topology of the containing sub-network. The ports at the boundary of the containing sub-network and the interconnection capability must fully represent, but not extend, the connectivity supported by the contained sub-networks and links. Therefore a higher level sub-network may be partitioned to show the level of detail required.

Thus in general, any sub-network may be partitioned into a number of smaller (contained) sub-networks interconnected by links.

The partitioning of a sub-network cannot extend or restrict its connectivity i.e.:

� The ports on the boundary of the containing sub-network and the interconnection capability must be represented by the contained sub-networks and links.

� The contained sub-networks and links cannot provide connectivity that is not available in the containing sub-network.


7.6

7 Usage of SDH NetworksSDH Layer Networks

PDH or ATM VP layer network

VC-11 VC-12 VC-2 VC-2-mc VC-3

VC-4 VC-4-Xc

Multiplex section

Regenerator section

Lower-order pathlayer network

Higher-order pathlayer network

Pathlayer

Sectionlayer

� The transport network can be decomposed into a number of independent layer networks with a client/server relationship between adjacent layer networks.

A layer network describes the generation, transport and termination of a particular characteristic information.

� Client/server relationshipAny two adjacent network layers are associated in a client/server relationship.Each transport network layer provides transport to the layer above and uses transport from the layer below.The layer providing transport is termed a server.The layer using transport is termed a client.

� VC-n path layerThe VC-n path layers can be divided into High Order Path layer and Low Order Path layer. They handle the termination of the high- or low order paths. This includes the termination and generation of the POH. Alarms and anomalies transmitted in this part of the signal arise at this layer. On the other direction a new overhead is created and overhead bytes can be added to it. Additionally the incoming signals are mapped into containers and the TUG structure (if necessary) is created.

� Regenerator section layer/ Multiplex section layerThe regenerator/multiplex section layer handles the RSOH/MSOH of the SDH signal. At multiplex section layer also the AU-pointer is processed.


7.7

7 Usage of SDH NetworksExample: Layers used by a Low Order Path

NE

PHYSICALCONNECTION

NE NE

LO PATH / TRAIL

PHYSICALCONNECTION

NE

PHYSICALCONNECTION

MS TRAILMS TRAILMS TRAIL

HO LINK CONNECTION HO LINK CONNECTION HO LINK CONNECTION

HO PATH / TRAILHO PATH / TRAIL

LO LINK CONNECTION LO LINK CONNECTION

� Client/server relationship between adjacent layers is one where a link connection in the client layer is supported by a trail in the server layer network.

Client

Server

Example: MS trail supports HO Link ConnectionHO trail supports LO Link Connection

� Link Connection: represents a pair of adaptation functions and a trail in the server layer.� A complete example of Layering is given in appendix C1

� A Trail defines a section inside an SDH network between two basic functions where any kind of overhead information (POH+SOH) is generated or analyzed. The trail definition exists for several transmission layers:

� RS Trail (RS layer) / MS Trail (MS layer)� VC-4 Trail (HO path layer)� VC-3 / VC-12 Trail (LO path layer)

� A Path is a specific kind of trail inside an SDH network between two basic functions that generate and analyze the Path Overhead (POH) of a Virtual Container. The path definition exists for the following transmission layers:

� VC-4 path (HO path layer)� VC-3 / VC-12 path (LO path layer)

trail

link connection


7.8

7 Usage of SDH NetworksDefinition of Reference points

AP APtrail

CTP CTP CTP CTP CTP CTP

connection connection connection

� Every trail is terminated by an AP: Access Point The information at the AP is called AI: Adapted Information, the payload and some parts of the path/section overhead.

� Every connection is terminated by a CTP: Connection Termination Point

� Two CTPs are combined to a CP: Connection Point, if they are connected in the same layer

� If the information in a CTP is given to/got from a termination function, the related reference is called a TCP: Termination Connection Point

� ITU-T definition: A bi-directional TCP consists of a pair of collocated unidirectional TCPs.

A unidirectional TCP is the binding of an output of a trail termination source to an input of a unidirectional connection or the output of a unidirectional connection to the input of a trail termination sink.


7.9

7 Usage of SDH NetworksRelation between Reference Points and Transport Entities

LOP layer

HOP layer

MS layer

RS layer

LOPA sink

LOP AP

LOPT sink

LOP TCP

HOPA sink

HOP AP

HOPT sink

HOP TCP

MSA sink

MS AP

MST sink

MS TCP

RSA sink

RS AP

RST sink

RS TCP

LOPA source

LOP AP

LOPT source

LOP TCP

HOPA source

HOP AP

HOPT source

HOP TCP

MSA source

MS AP

MST source

RS LC

RSA source

RS AP

RST source

RS TCP

RS trail

MS LC

MS trail

HOP LC

HOP trail

LOP LC

LOP trail

NE 1 NE 2

MS TCP

� LC : Link Connection

� : Adaptation

� : Termination

� : Bi-directional Trail Connection

� The complete functional model (G.805) is given in Appendix C2.


7.10



7 Usage of SDH Networks Evaluation

� Objective: to be able to describe the layering of SDH Networks



8 The Functional Model


8.2

8 The Functional ModelSession presentation

� Objective: to be able to describe the functional model in SDH

� program:

� 8.1 Layer Function : Adaptation

� 8.2 Layer Function : Termination

� 8.3 Layer Function : Connection

� 8.4 Atomic & Basic Functions in a Network Element


8.3

8 The Functional ModelLayer Function: Adaptation

Y/Z Y/Z

Y Y

Y

Layer Z

Layer Y

Layer XSink Source

Client

Server


8.4

8 The Functional ModelLayer Function: Termination

Y/Z Y/Z

Y Y

Y

Layer Z

Layer Y

Layer XSink Source

Client

Server


8.5

8 The Functional ModelLayer Function: Connection

Y/Z Y/Z

Y Y

Y

Layer Z

Layer Y

Layer XSink Source

Client

Server


8.6

8 The Functional ModelAtomic and Basic Functions in a Network Element

OSn or ESn

RSn

RSn/MSn

MSn

MSn/Sn

Sn

Sn/Sm

Snm Sn

Sm

MSn/MSnP

MSnP

MSnPC

SPI

RST

MST

MSP

MSA

HPC

HPT

HPA

LPC

Regenerator

Low Order

PathLayer

HighOrderPathLayer

MultiplexSectionLayer

SectionLayer

PhysicalLayer

HPOM

OSn/RSn or ESn/RSn

Sm

Sm/Pq

LPT

LPA

EqPPI

Eq/Pqs or Eq/Pqx

Sns

Smm

Sns

LPOM

HSUT

Sms

Sms

LSUT

SmD

SmD/Sm

LTCT

LTCA

SmDmLTCM

SnD

SnD/Sn

HTCT

HTCA

SnDnHTCM

Sn/PqLPA


8.7



8 The Functional Model Evaluation

� Objective: to be able to describe the functional model in SDH



9 Alarm and Error Handling


9.2

9 Alarm and Error HandlingSession presentation

� Objective: to be able to describe the way the alarms are managed in an SDH network

� program:

� 9.1 Communication Alarms

� 9.2 Alarm Indication Signal : AIS

� 9.3 Remote Defect Indication : RDI

� 9.4 Alarm and Error Processing within an NE

� 9.5 Explanation of Alarm and Error Codes

� 9.6 Alarm and Error Processing

� 9.7 Performance Monitoring : PM

� 9.8 Tandem Connections


9.3

9 Alarm and Error HandlingCommunication Alarms

SDH-Network

ADMMSNDXC

ADMMSNDXC

RegeneratorADMMSNDXC

PDH140Mbit/s

PDH2 Mbit/s

� Communication alarms can be subdivided in primary and secondary alarms and alarms which have to be send in reversed direction.

� The most common primary alarms are:

� LOS Loss of Signal � LOF Loss of Frame

� Secondary alarms in forward direction are:

� AIS Alarm Indication Signal� SSF Server Signal Failure: Alarm detected in a Client Layer indicating that in a

Server Layer another Alarm has been detected before

� Secondary alarms in reversed direction are:

� RDI Remote Defect Indication

� Errors are bit errors of PM: Performance Monitoring


9.4

9 Alarm and Error HandlingAlarm Indication Signal - AIS

RSOH

1 1

1 1

1

1

1

1

1

1

MS - AIS

AU - AIS

TU – AIS

RSOH

1 1

1

1

1

1

1

1MSOH

RSOH

MSOH

AU-PointerPOH

111

1

1

� AIS: Alarm Indication Signal, means the signal is adapted to all ONES

� It is generated to replace the normal SDH signal when it contains a defect condition

� In this way it prevents consequential failures or alarms in the following NEs

� The AIS alarm is send to the following NE in forward direction

� AIS can be identified as:� MS-AIS: Multiplex Section Alarm Indication Signal

� the MS-AIS is generated as a consequence of a LOS or LOF � on the receiving side of a regenerator element� complete payload and MSOH are set to one

� AU-AIS : Administrative Unit Alarm Indication Signal� AU-AIS is characterized by all ones in the complete Administrative Unit� all bits of AU-pointer and payload are set to one

� TU-AIS: Tributary Unit Alarm Indication Signal� a port that detects a serious alarm on the receiving side generates a TU-AIS � all bits of TU-pointer and TU-payload are set to one


9.5

9 Alarm and Error HandlingRemote Defect Indication - RDI

HP-RDI

8...1

1

LP-RDI

8...1

1

MS-RDI

8...1

011 K2-Byte

G1-Byte

V5-Byte

K2

G1

V5

� RDI: Remote Defect Indication, signal which is returned to the transmitting NE upon detecting a LOS, LOF or AIS

� RDI was previously known as FERF (Far End Receiver Failure)

� RDI can be identified as:� MS-RDI: Multiplex Section Remote Defect Indication

� transmitted via the K2-Byte in the MSOH� HP-RDI: High-order Path Remote Defect Indication

� transmitted via the G1-Byte in the HP-POH� LP-RDI: Low-order Path Remote Defect Indication

� transmitted via the V5-Byte in the LP-POH


� Alarm and Error Processing within an NE

PhysicalSection Layer

RegeneratorSection Layer

MultiplexSection Layer

Higher OrderPath Layer

Lower OrderPath Layer

LOF

RS-TIM

RS-BIP

MS-AIS

MS-BIP

MS-REI

AU-AIS

AU-LOP

HP-UNEQ

HP-TIM

HP-BIP

HP-REI

HP-RDI

TU-AIS

TU-LOP

TU-LOM

TU-PLM

LP-UNEQ

LP-TIM

LP-BIP

LP-REI

LP-RDIPDH-AIS

TU-AIS

TU-AIS

TU-AIS

AU-AIS

MS-AIS

V5

V5

V5

V5

J2

V5

C2

H4

G1

G1

B3

J1

C2

K2

M1

B2

K2

B1

J0

A1/A2

LOS

OSr/ESr RSn

MSn

Sn

Sm

MSn/Sn

Sm

Sm/PG

Sn

Sn/Sm

LP-PLM

MS-RDI

Detection

Generation


� Explanation of Alarm and Error Codes

Alarm / Error Detection criteriaLOS Loss of Signal Drop of incoming optical power level causes high bit error

rate OOF Out of Frame A1, A2 incorrect for ³ 625 µs LOF Loss of Frame If OOF persists for ³ 3ms (to be defined)RS BIP Error

Regenerator Section BIP Error (B1)

Mismatch of the recovered and computed BlP-8 Covers the whole STM-N frame

RS-TIM Regenerator Section Trace identifier Mismatch

Mismatch of the accepted and expected Trace Identifier in byte J0

MS BIP Error

Multiplex Section BIP Error (B2)

Mismatch of the recovered and computed N x BIP-24 covers the whole frame, except RSOH

MS-AIS Multiplex Section AIS K2 (bits 6, 7, 8) = 111 for ³ 3 frames MS-REl Multiplex Section

Remote Error IndicationNumber of detected B2 errors in the sink side encoded in byte M1 of the source side

MS-RDI Multiplex Section Remote Defect Indication

K2 (bits 6, 7, 8) = 110 for ³ z frames (z = 3-5)

AU-AIS Administrative Unit AIS All "1" in the AU pointer bytes H1, H2AU-LOP Administrative Unit Loss

of Pointer8 to10 NDF enable, 8 to 10 invalid pointers

HP BIP Error

HO Path BIP Error (B3) Mismatch of the recovered and computed BIP-8 Covers entire VC-3

HP-UNEQ HO Path Unequipped C2 = "0" for ³ 5 framesHP-TIM HO Path Trace Identifier

MismatchMismatch of the accepted and expected Trace Identifier in byte J1

HP-REI HO Path Remote Error Indication

Number of detected B3 errors in the sink sideencoded in byte G1 (bits 1, 2, 3, 4) of the source side

HP-RDI HO Path Remote Defect Indication

G1 (bit 5) = 1 for ³ z frames (z = 3, 5 or 10)

HP-PLM HO Path Payload Label Mismatch

Mismatch of the accepted and expected Payload Label in byte C2

TU-LOM Tributary Unit Loss of Multiframe

H4 (bits 7, 8) multiframe not recovered for X ms X = 1 to 5 ms

TU-AIS Tributary Unit AIS All "1" in the TU pointer bytes V1, V2

TU-LOPLoss of Pointer

8 -10 NDF enable, 8-10 Invalid pointers

LP BIP LO Path BIP Error Mismatch of the recovered and computed BIP-8 (B3) or BIP-2 (V5 bits 1, 2). Covers entire VC-n

LP-UNEQ LO Path Unequipped VC-3: C2 = "0" for >= 5 frames, VC-m (m = 2, 11, 12): V5 (bits 5, 6, 7) = 000 for ³ 5 multiframes

LP-TIM LO Path Trace Identifier Mismatch

Mismatch of the accepted and expected Trace Identifier in byte J1 (VC-3) or J2

LP-REI LO Path Remote Error Indication

VC-3: Number of detected B3 errors in the sink side encoded in byte G1 (bits 1, 2, 3, 4) of the source side,

VC-m (m = 2, 11, 12): If one or more BIP-2 errors detected in the sink side, byte V5 (bits 3) = 1 on the source side

LP-RDI LO Path Remote Defect Indication

VC-3: G1 (bit 5) = 1 for ³ z frames, VC-m (m = 2, 11, 12):V5 (bit 8) = 1 for ³ z multiframes (z = 3, 5 or 10)

LP-PLM LO Path Payload Label Mismatch

Mismatch of the accepted and expected Payload Label in byte C2 or V5 (bits 5, 6, 7)

Tributary Unit

TU-PLM Tributary Unit Payload Table Mismatch

Mismatch of the accepted and expected Payload Labelin byte V5

Error


9.8

9 Alarm and Error HandlingExample Network

SDH-Network

ADMMSNDXC

ADMMSNDXC

RegeneratorADMMSNDXC

PDH140Mbit/s

PDH2 Mbit/s

Regenerator Section Regenerator Section

Multiplex SectionMultiplex Section

Trail / Path

Regenerator Section

� Regenerator Section: between regenerators

� Multiplex Section: between multiplexers

� Trail / Path: End to End connection

� Examples for errors:� Interruption of a line� No input signal� Failure of a NE


9.9

9 Alarm and Error HandlingAlarm and Error Processing in a Regenerator

MS-AISLOS

LOF

RS-TIM

RS-BIP

MS-AIS

(PM)

RS

1 / MS

1

RS

1

OS

1 / RS

1

OS

1

RS

1 / MS

1

RS

1

OS

1 / RS

1

OS

1

Detection

Generation

RSOH

1 1

1 1

1

1

1

1

1

1

� MS1 Multiplex Section layer, level STM-1� OS1 Optical Section layer, level STM-1� PM Performance Monitoring� RS1 Regenerator Section layer, level STM-1

� The regenerator is the only NE which can cause the MS-AIS alarm because the RSOH is built completely new.

� In a multiplexer also the MSOH is rebuilt and the output then is an AU-AIS.


9.10

9 Alarm and Error HandlingAlarm and Error Processing in a Multiplexer: VC-4 Passthrough

S4

MS

1 / S4

MS

1

RS

1 / MS

1

RS

1

OS

1 / RS

1

OS

1

MS

1 / S4

MS

1

RS

1 / MS

1

RS

1

OS

1 / RS

1

OS

1

LOS

LOF

RS-TIM

RS-BIP

MS-AIS

MS-BIP

MS-REI

MS-RDI

MS-AIS

AU-AIS

(PM)

AU-AIS

(PM)

Detection

Generation

(PM)

RSOH

1 1

1

1

1

1

1

1MSOH

� MS1 Multiplex Section layer, level STM-1� OS1 Optical Section layer, level STM-1� PM Performance Monitoring� RS1 Regenerator Section layer, level STM-1� S4 VC-4 path layer


9.11

9 Alarm and Error HandlingAlarm and Error Processing in a Multiplexer: VC-4 Termination

S4

MS

1 / S4

MS

1

AU-AISAU-LOP

HP-UNEQHP-TIMHP-BIPHP-REIHP-RDI

AU-AIS

TU-AIS

TU-AIS

S4

TU-AIS(PM)

Detection

Generation

(PM)

S12

S4 / S

12

RSOH

MSOH

AU-PointerPOH

111

1

1

� MS1 Multiplex Section layer, level STM-1� PM Performance Monitoring� S4 VC-4 path layer


9.12

9 Alarm and Error HandlingAlarm Processing via a complete Network: Path fault

NE A NE B NE C

NE D

Reg. EReg. F

LO-passthrough HO-passthrough

LOS

2Mbit/s

� Assumptions:� Bi-directional 2Mbit/s-Path between NE C and NE D via NE B, A, F, E� Path fault: Unidirectional interruption (C →→→→ D) in section A-F

� Alarms in direction C →→→→ D :� NE F: detection: LOS

generation: MS-AIS � NE E: -� NE D: detection: MS-AIS, AU-AIS, TU-AIS, generation: PDH-AIS

� Alarms in direction D →→→→ C :� NE D: generation: MS-RDI, HP-RDI, LP-RDI� NE E: -� NE F: -� NE A: detection: MS-RDI, HP-RDI � NE B: -� NE C: detection: LP-RDI


9.13

9 Alarm and Error HandlingAlarm Processing via a complete Network: Reference fault

NE A NE B NE C

NE D

Reg. EReg. F

LO-passthrough HO-passthrough

LOS

2Mbit/s

� Assumptions� Unidirectional 2Mbit/s-Path between NE C and NE D via NE B, A, F, E� Reference fault: Loss of input signal

� Alarms in direction C →→→→ D :� NE C: detection: LOS� NE D: generation: PDH-AIS


9.14

9 Alarm and Error HandlingPM Basics

Error checksum Block sizemax. number of

block errors per second

B1 (RSOH) STM-N 8.000

B2 (MSOH) 801 bits * N 192.000 * N(STM-N)

B3 (HP-POH) VC-4VC-3

8.000

8.000V5 (LP-POH) VC-12 Multiframe 2.000

� Performance Monitoring (PM) is used to monitor the signal quality� The signal quality depends on the occurrence of:

Bit Errors = Anomalies

Alarms = Defects

� The performance parameters are based upon the measurement of Blocks :a set of consecutive bits associated with the path and the section

� Each block is monitored by calculating a checksum e.g. Bit Interleaved Parity (BIP). These block errors can be monitored on several layers inside each NE:

B1 = BIP8 for a regeneration section

B2 = N*BIP24 for a multiplex section (N= 1, 4, 16, 64)BIP24 STM-1BIP96 STM-4 BIP384 STM-16BIP1536 STM-64

B3 = BIP8 for VC-4 or VC-3 path (HP)

V5 = 2 bits perform a BIP2 of VC-2, VC-12 or VC-11 path (LP)


9.15

9 Alarm and Error HandlingPrinciples of data collection

Monitored seconds

Defects ?

Anomalies ?

% EB >= 30 ?

cES = cES + 1 cES = cES + 1

cBBE = cBBE + EB(s) cSES = cSES + 1

End

Yes

Yes

Yes

No

No

No

Extracted from G 826

� Errored Block (EB) Block containing one or more errored bits.

� Errored Second (ES) A second containing one or more errored blocks.

� Severely Errored Second (SES) A second containing at least 30% of errored blocks or at least one defect.

� Background Block Errors (BBE) Errored block (EB) occurring outside a severelyerrored second (SES).


9.16

9 Alarm and Error HandlingDefinition of Unavailability

SESES which is not a SESNon errored second

10 sec < 10 sec 10 sec< 10 sec

t in sec

End of detection :

ES := ES + x SES := SES UAS := UAS - 10

Begin of detection :

ES := ES - 10 SES := SES - 10 UAS := UAS + 10

Unavailable Time (UAT)

Inhibition of counters:ES / SES / (BBE)

Available Time

x

� Unavailable Time (UAT) A period of unavailable time (UAT) begins at the onset of 10 consecutive SES events. These 10 seconds are considered to be part of unavailable

time. A new period of available time begins at the onset of 10 consecutive non-SES events.

� Unavailable Second (UAS) An unavailable second (UAS) is a second which is part of the Unavailable Time (UAT).


9.17

9 Alarm and Error HandlingNear End / Far End counters

NE A

STM-N with errors

Far End Counters:

FEBBEFEESFESESFEUAS

Near End Counters:

BBEESSESUAS

STM-N with REI

NE B

� Near End counters are incremented if in the received STM-N frame anomalies (bit errors) or defects (alarms) have been detected.

� Far End counters are incremented if the transmitted STM- N frame was erroneous: anomalies (bit errors) or defects (alarms).

� The Network Element which is transmitting an errored signal, is informed about the bit errors by receiving Remote Error Indications (REI)

� MS-REI: M1-Byte inside MSOH contains the number of erroneous blocks detected in B2

� HP-REI: G1-Byte (Bits 1 to 4) of HP-POH contains the number of erroneous blocks detected in B3

� LP-REI: V5-Byte (Bit 5) of LO-POH: there is the indication if BIP2 errors are detected (<>0)

� The transmitting Network Element is informed about the alarms by receiving Remote Defect Indications (RDI)


9.18

9 Alarm and Error HandlingWhy Tandem Connections

[total biterrors]

PathSink

PathSource

Near end bit errors counted by path monitor (PM) [location]

Bit errors added before domain 1

Bit errors added in domain 1

Bit errors added between domain 1 and domain 2

Bit errors added indomain 2

Domain 1 Domain 2

VCn-Path

Inter DomainLink

� In transmission networks it is normal that signals are transported over multiple domains managed by different network operators

� The signal is entering the network at the Path Source (SDH POH is added) and leaves the network at the Path Sink (SDH POH is terminated)

� Statistic models assume that within each domain and inter-domain link equally distributed bit errors are inserted into the signal

� Problem:� It is not possible to check the performance of domain1 and domain 2 or the link between the two domains� Usage of the Performance Monitoring counters on path basis would indicate only the overall bit errors without any hint

where and how many bit errors are introduced

� Solution:� Tandem Connection Monitoring is the solution for this problem � The TCM standards were approved by the ITU-T in 2000 (G.783), in 1996 (G.707)


9.19

9 Alarm and Error HandlingFunction of Tandem Connections

VCn-Path

Near end bit errors counted by Tandem Connections (TC)

skso

TC 1

so sk

TC 12

PathSink

PathSource

Domain 1 Domain 2Inter Domain

Link

skso

TC 2

so: sourcesk: sink

[location]

[total biterrors]

� The complete VCn path is virtually split into fragments, where an independent monitor considers only effects on this fragment. Tandem Connection (TC) monitors the performance (bit errors and alarms) on a configurable fragment of the path.

� TCs are independent from each other. Each operator can decide where and when to use a TC.

� Full PM is supported

� TCs are applicable for VC12 / VC3 / VC4 / VC4-nc signals

� In the example above the operator created three Tandem Connections for supervising the performance of the signal in a specific domain

� TC1 counts only bit errors that have been added in Domain1 .� TC12 counts only bit errors that have been added on the Inter Domain Link� TC2 counts only bit errors that have been added in Domain2 . � The function TC12 sk (sink) is created before matrix, therefore this TC is called “TC Before Matrix ”, “Ingressing TC ”or

“TCT RX” . This TC supervises a domain external signal arriving at the domain ingress (e.g. a inter domain link)

� The functions TC1 sk and TC2 sk are created behind matrix, therefore they are called “TC After Matrix ”, “Egressing TC ”or “TCT TX”. This type of TCs allow to supervise a domain internal signal shortly before the domain egress.


9.20

9 Alarm and Error HandlingOverhead Bytes used for Tandem Connections

REI OEI

PayloadG1F2H4F3K3N1

C2B3J1

Virtual Container (VC-4, VC-3)

Number of bit errors detected by TC source

frame 1-8: FASframe 9-72: 64*2 Bit= 16Byte TC-TIframe 73: TC-RDIframe 74: ODIframe 75,76: all ‘0’

N1 used for TCs

1 2 3 4 5 7 86

� Existing path is not affected by the TC, which is transparent for the path layer

� For a working TC it´s necessary that the start and end point exchanges management information in a bidirectional way. Therefore TC uses a part of the already existing Path Overhead (POH)

� For the VC4 or the VC3 path the N1 byte is used (see figure above), for the VC12 path the N2 byte of the VC12 multiframe is used

� Every modification of the N1 byte has to be compensated so that no BIP failure occurs because of this modification

� N1byte:� Bit 1 - 4 contains number of errors in the signal before the TC starts (range=0-8) calculated via 8

bits of BIP8 (B3 byte)� Bit 5: Remote Error Indication (REI) is used to indicate block errors to the TC-source, necessary for Far End

PM� Bit 6: Outgoing Error Indication (OEI) necessary for counting of outgoing Far End PM data� Bit 7 - 8 contains several information in a multi frame (consisting of 76 frames)

� FAS Frame Alignment Signal� TC-TI Tandem Connection - Trail Identification� TC-RDI Tandem Connection- Remote Defect Indication� ODI Outgoing Defect Indication


9.21

9 Alarm and Error HandlingTandem Connection Termination: TCT

SDH portSDH port

Path

Path

Domain 1

N1=0 N1=0

N1=0 N1=0

BBE = 2N1:=2

NE 1

SPIRSTMSTMSA

BBE = 6N1 = 2

NE_BBE := 6 - 2 =4

NE x

TC 1 (Egressing Tandem Connection)

TC after Matrix

TC afterMatrix

SPIRSTMSTMSA

SPIRSTMSTMSA

SPIRSTMSTMSA

� Example:In NE 1 and NE x of Domain 1 a “TC after Matrix” is configured, to find out how many bit errors happened inside Domain 1 on the VC-4 path

� TC Source of NE 1 calculates arriving bit errors (BBE = 2) and inserts the number into Bit1-4 of the N1 byte

� Between NE 1 and NE x 4 additional bit errors occur

� TC Sink of NE x calculates the current bit errors: 2+4=6 of the signal (using BIP). These are called “outgoing bit errors”because they’re in the outgoing signal of the TC Sink

� TC Sink of NE x calculates the bit errors on TC segment: (bit errors detected) - (N1 value); NE_BBE: 6 - 2 =4

� As for the path we have signaling information to do Far End PM on bidirectional TCs:� NE_BBE sent in backward direction as REI (Remote Error Indication)� Alarms on the TC Segment sent in backward direction as RDI (Remote Defect Indication)

� Outside an TC the N1 byte is set to 0 to indicate that no TC is created on this path segment


9.22

9 Alarm and Error HandlingTandem Connection Monitoring: TCM

SPIRSTMSTMSAPath

SDH Port

TCmRX

Before Matrix

TC

SDH Port

TCmTX

After Matrix

SPIRSTMSTMSA

� Additional to the Tandem Connection Termination (Source and Sink function) a Monitor function can be used for:� TCM before Matrix (TCm RX) to supervise for example the TC of a inter domain link

� TCM after Matrix (TCm TX) to supervise for example the TC of a domain

� Creation of TC terminations without failures. The following creation rules have to be fulfilled:

� NO “Nesting” allowed

� NO “Overlapping” allowed

� “Cascading” is allowed

� The TC Monitor function (same as the TC sink) is able to detect:� Bit errors� Alarms

� SSF: Server Signal Failure, (consequence of a Loss of Pointer (LOP))� UNEQ: Unequipped, (N1 == 0, no TC info received)� LTC: Loss of Tandem Connection, (N1 <> 0 and no multi frame detected)� TC-TIM: Tandem Connection Trail Identifier Mismatch (difference between expected and

received TC-identifier)� DEG: Degraded Signal, (TC bit errors exceeds the degraded threshold)


9.23



9 Alarm and Error Handling Evaluation

� Objective: to be able to describe the way the alarms are managed in an SDH network



10 Protection and Restoration


10.2

10 Protection and RestorationSession presentation

� Objective: to be able to describe the different kinds of protection in SDH

� program:

� 10.1 Equipment Protection : EPS

� 10.2 Network Protection

� 10.3 Network Restoration


10.3

10 Protection and RestorationEquipment Protection: EPS

W

P

Equipment Protection Switching(EPS)

Multiplex Section Protection Linear Trail (MSP)

2

Protection against equipment failure Protection against equipment failureand line failure

P

2

1+1 1:N

W

W

W

W

P

W

P

1+1

� Equipment Protection Switching (EPS):� The Matrix, Clock, Control and Power Conversion Part System is protected via EPS (1+1)� All electrical I/O boards are optionally protected via EPS (1:N)

� Multiplex Section Protection - Linear Trail (MSP)� Contains two kinds of protection

� Equipment protection inside the NE� Line protection between two adjacent multiplex elements

(further information is provided in Chapter "Network Protection")� All optical I/O boards inside the NE are optionally protected via MSP (1+1)


10.4

10 Protection and RestorationEPS 1+1

Equipment 1

Equipment 2

� The 1+1 EPS protection type means that one working equipment is protected by one redundant equivalent.

� The EPS mechanism ensures that transmission is continued and the faulty equipment can be exchanged should equipment failure occur.

� The mode of 1+1 EPS protection is non revertive.


10.5

10 Protection and RestorationEPS 1:N

Equipment 1

Equipment 2

Equipment N

Equipment P

Line 1

Line 2

Line N

� The 1:N EPS protection type means that N working pieces of equipment are protected by just 1 protecting equivalent.

� During normal operation without equipment failure the protecting equipment is inactive.

� The mode of 1:N EPS protection is revertive.


10.6

10 Protection and RestorationProtection Mechanisms against Network Faults

Linear structure

Item to be protectedProtection architecture

Protection mechanism

SNCP/I

SNCP/N

Linear MSP

MS-SPRING

connection dedicatedto a Path

Section

Linear structure

Ring structure

� MSP Multiplex Section Protection (linear)MS-SPRING Multiplex Section Shared Protection in a RingSNCP/N Sub Network Connection Protection with non intrusive monitoringSNCP/I Sub Network Connection Protection with inherent monitoring

� The protection mechanisms are defined by ETSI and ITU-T at section or path level.

� Section protection mechanisms on a � linear network: Linear MSP redundancy at section level between two nodes.� ring network: MS-SPRING loopback to bypass the section declared faulty.

� Protection mechanisms at path level:SNCP/N, SNCP/I broadcast of the signal to be transported, selection of the best signal.


10.7

10 Protection and RestorationSub Network Connection Protection: SNCP

Sub Network

Sub Network

VC-n VC-n

broadcast

selection

_____ working path ----- protecting path

broadcast

selection

� SNCP: Sub Network Connection Protection is performed on the path (VC-n) level

� Dedicated protection mechanism: 1+1.

� Signal is broadcasted on the working and protecting path, and selected upon reception.

� SNCP is also called PPS: Path Protection Switching

� 2 operating modes:� revertive: traffic is switched back to the working channel when the fault has

disappeared, once the wait-to-restore time (5 to 12 minutes) has elapsed.

� non revertive: no switch back.


10.8

10 Protection and RestorationSNCP: switch criteria

Switching criteria(external commands)

Switching criteria(automatic)

Sub Network

Sub Network

_____ working path----- protecting path

� SNCP/I: Sub Network Connection Protection with inherent monitoring.

� SNCP/N: Sub Network Connection Protection with non intrusive monitoring.

� Switching criteria - Automatic:

SNCP-I: SNCP-N:LOS LOSLOF LOFLOP LOPAU-/TU-AIS AU-/TU-AIS

HP-/LP-UNEQHP-/LP-E-BERHP-/LP-DEGHP-/LP-TIMB3-/BIP-2-SD

� Switching criteria - External commands:� protection mechanism lock � forced protection switching � manual protection switching� forced switching to the normal channel� manual switching to the normal channel


10.9

10 Protection and RestorationSection Protection on a Linear Network: MSP

Multiplex SectionNE A NE B

TX

TX

TX

TX

TX

RX 1+1 protection

RX 1:1 protection

RX

RX 1:N protection

RXX

Protecting

Working

Protecting

Working

Working

Low priority lineProtecting

High priority lineWorking

� Protection called MSP: Multiplex Section Protection

� MSP (linear) is also called APS: Automatic Protection Switching� Protection strategies

� 1+1 = 1 plus 1 dedicated to protection capacity can be used, non revertive

� 1: N = 1 for N protection for low priority purpose whichis suspended in case of protection event, revertive

� The configuration as 1:1 protection is used in the case of

� APS: Automatic Protection Switching

� EPS: Equipment Protection Switching

� Switching criteria:� MS-AIS� LOS� LOF


10.10

10 Protection and RestorationMSP 1+1

TX

RX

Line A

Multiplex section

Line B

RX

TX

selectionbroadcast

broadcastselection

� The signal is transmitted simultaneously on both lines: broadcast

� The receiving signal is selected on reception.

� Maximal useful rate: rate of a single line

� 1 + 1 protection may be single ended without using protocol K1 K2

� 1 + 1 protection is a dual ended protection when protocol K1 K2 (MSOH) is used: used for spare connection for both directions


10.11

10 Protection and RestorationMSP 1:1

TX

TX

RX

RX Low priority line

High priority line

RX

RX

TX

TX

Multiplex section

RX

TX

RX

TX

TX

RX

TX

RXextra traffic extra traffic

� When the protected/working line operates normally, the protecting line may be used for “extra traffic”: low priority line

� Maximal useful rate = sum of both lines’ rates.

� EPS: a spare unit/board fully replaces a faulty unit/board


10.12

10 Protection and RestorationSection Protection on a Ring Network: MS-SPRING (2 fiber)

Overview of the ring

Detailed view of the ring

Node A Node B

Node D Node C

Node A Node BTransmission direction

Section overheadNormal traffic channels

Protection channels


Protection channelsSTM-16 fiber:Normal channel: AU4 #1-8Protection channel: AU4 #9-16

� Protection called MS-SPRING: Multiplex Section Shared Protection in a Ring it enables a larger flow of traffic to be processed than with other resources

� Shared Protection: protection architecture in which m protection entities are shared between n traffic entities (m:n).Protection entities may be used to transport additional traffic.

� The ring protection switching protocol is performed by the K1 and K2 bytes in the protection channels MSOH.

� The communication protocol must enable the installation of up to 16 nodes in a ring.

� Principle: LOOPBACK to bypass the sections declared faulty

� Purpose: Share the same protection among different resources

� Two types of ring with MS-SPRING: 2-fiber ring and 4-fiber ring for STM-16 fiber

� Two-fiber rings with shared protection:� Each fiber simultaneously carries both, normal channels and protection channels:

8 working AU4 #1-8 and 8 protection AU4 #9-16 for STM-16 fiber� When ring switching is invoked, the VCs which carry the normal channels are switched over to the VCs carrying the

normal or the protection channels going in the opposite direction.

� Switching criteria: MS-AIS / LOS / LOF


10.13

10 Protection and RestorationTwo fiber MS-SPRING: failure study

WORKING CHANNELS

PROTECTING CHANNELS

(*) All protecting AU-4 are put in passthrough in the 1st, 4th, 5th and 6th NE

PROTECTEDSIGNAL

PROTECTEDSIGNAL

(*)

1

6

2

5

3

4

1 fiber carries bothtype of channels

BRIDGE SWITCH BRIDGE

Failure

(*) (*)

SWITCH

� Signal flow through NEs:without failure: NE1, NE2, NE3, NE4 with failure in NE 2: NE1, NE2, NE1, NE6, NE5, NE4, NE 3, NE4

� BRIDGE: sends the traffic of the working channel additionally to the opposite port via the protecting channel (broadcast function)

� SWITCH: uses for receiving traffic the protecting channels of the opposite port (selection function)


10.14

10 Protection and RestorationSpan Protection on a Ring Network: MS-SPRING (4 fiber)

Fiber carrying the normal trafficFiber carrying the protection traffic

Overview of the ring

Detailed view of the ring

Node A Node B

Node D Node C

Node A Node BTransmission direction



Section overheadProtection channels

Section overheadProtection channels

� Four fibers for each ring span.

� The normal and the protection channels are materialized on different fibers.

� Four-fiber rings enable ring switching for protection purposes, as well as span switching, but not both simultaneously.

� 4f-MS-SPRING supports:� span switching� ring switching

� A fault condition present only on the working link determines a SPAN PROTECTION: High Priority traffic is restored by switching to the protection channels of the same span.

� A fault condition present on both working and protection links determines a RING PROTECTION: The High Priority traffic travelling the failed span is restored by switching to the protection channels travelling in the opposite direction (away from the failure).

� Switching criteria: MS-AIS / LOS / LOF


10.15

10 Protection and RestorationFour fiber MS-SPRING: failure study

1 2 3

Failure

Working channel

Protection channel

Normal path

Path after span failure

1 fiber carries onetype of channel

6 5 4

� SPAN switching: the protection channels of the affected span are used to carry the working channels. The corresponding low priority connections (protection channel) crossing the span are preempted (AU-AIS insertion on LP paths).

� When the working channel operates normally, the protecting channel may be used for “extra traffic”: low priority line / traffic


10.16

10 Protection and RestorationNetwork Restoration

A B C

F E

D

VC-n

A B C

F E

D

VC-n

Failure

Failure

DXC

any NE

A few seconds later

VC-n

VC-n

� An alternative approach to the network protection is the network restoration. � The networks contains extra capacity which can be used for the recovery of any failed traffic. � The spare capacity can be reduced drastically compared to the 1+1 protection scenarios.

� DXC supports together with SDH Network Manager a restorable network providing:� Path restoration on VC-n level� MSP and SNCP� SNCP protection and restoration combined

� All the VC-n connections of the network are configured and supervised by the SDH Network Manager. With its knowledge about the routes and bearers of the network as well as of the current interconnections it can recalculate alternative routings for possible network failures.

� In case of a failure, reported from one (or several) DXC, the SDH Network Manager analyses the location of the failure and initiates the relevant restoration scenario:

� Working circuit path: ABCD� Failure on section: BC� NMS decides optimum routing: e.g. AFECD� The recalculated cross connection commands are sent to the relevant DXC which immediately performs them.


10.17



10 Protection and Restoration Evaluation

� Objective: to be able to describe the different kinds of protection in SDH



11 Network Synchronisation


11.2

11 Network SynchronisationSession presentation

� Objective: to be able to describe the principles of synchronisation of SDH networks

� program:

� 11.1 Synchronisation Distribution

� 11.2 Clocks Types and Distribution in the Network

� 11.3 Synchronisation Diagram

� 11.4 Synchronous Equipment Timing

� 11.5 Synchronisation Signals : Quality and Priority

� 11.6 Linear Networks without SSM

� 11.7 Linear Network with SSM


11.3

11 Network SynchronisationSynchronization Distribution

PRC

SSU SSU SSU

� PRC: Primary Reference ClockSSU: Synchronization Supply Unit

� The synchronization networks architecture must accept faults (path cutoffs, equipment failures) providing auxiliary paths and spare clock systems.

� A synchronization plan must be set up to ensure that synchronous NEs in a network really run synchronously. This plan indicates the way each NE is synchronized.

� Strictly forbidden are synchronization loops: i.e. an NE receives a sync signal it has generated, via a sequence of slave clocks.

� Master-Slave synchronization:� The PRC provides synchronization to the first node hierarchical level� These nodes provide synchronization to the next hierarchical level� Stability and precision level defined for each level, 4 levels maximum

� The PRC is doubled (tripled in some countries) on different sites (for safety), one acting as the master and the others as slaves.

� Degradation of the PRC due to the justification during multiplexing of a higher-order signal (jitter).


11.4

11 Network SynchronisationClock types and distribution in the Network

SEC

11

1

10

20

60

PRCPrimary Reference Clock (G.811):

Rubidium-clock or GPS: 10-11 / day frequency drift (1 slip in 145 days)(Cesium-clock: 10-13 / day frequency drift)

Synchronization Supply Unit (G.812):

Synchronous Equipment Clock (G.813): 10-8 / day frequency drift (1 slip in 3,46 h)

Transit node: G.812T (SSU A): 10-9 / day frequency drift

Local node: G.812L (SSU B): 2*10-8 / day frequency drift

SSU

SEC SEC SECSEC SEC SECSEC SEC SECPRC SSU SSU

� Do not exceed 60 network elements in total

� SSU is used for refreshing synchronization signals after 20 network elements

� No more than 10 SSU in a chain

� The PRC provides the best clock accuracy, which decreases via the SSU up to the SEC

� The SSUs are located at strategic nodes: they are designed to filter the accumulated jitter and wander and have good stability in holdover mode.

� Holdover Mode: If the NE looses its reference clock, it enters the Holdover Mode to providesynchronization at the last average of the phase locked frequency

� Free running Mode: The NE operates at the frequency of its own generator/oscillator without any timing reference


11.5

11 Network SynchronisationSynchronization Diagram

PRC level

SSU level

SEC level

PRC

SSU

MSP

SSU

SSUSSU

SSU

SSU

SSU

SSU

PRC

NE

NE containing SSU

� The lines of the SSU level represent the synchronization links carried by the STM-N signals.

� A synchronization link has three parts:� The 2-MHz link between the SSU and SEC (T3 access).� The 2-MHz link between the last SEC (T4 access) and the SSU.� SDH sections transmitting the synchronization and the SSM: Synchronization Status

Message (indicates quality of transmitted clock)


11.6

11 Network SynchronisationSynchronous Equipment Timing

Selector

A

Selector

C

Selector

B

Squelch

SETG

Squelch

T1

T2

T3

T4

T0

Oscillator

SSUoptional

referenceinputs

� Depending on specific NE more reference inputs (T1, T2, T3) are possible.� T0 SDH equipment internal clock� T1 2 MHz signal derived from an STM-N port (SDH)� T2 2 MHz signal derived from a 2 Mbit/s port (PDH)� T3 2 MHz signal of external clock

(coming from: separate clock network / SSU / PRC)� T4 Sync output of an SDH equipment, clock signal send to another NE

� SETG Synchronous Equipment Timing Generator (PLL)

� Squelch Function used to inhibit a clock below a certain quality level(e. g. in case of signal faults of the reference signal)upon detection of signal faults (LOS, LOF, MS-AIS, degraded errors rate)

� Selector Selection of timing reference according SSM algorithm (manual selection by operator is also possible)

synchronization source,

reference inputs


11.7

11 Network SynchronisationSynchronization Signals: Quality and Priority

5PRCT3

4SSUT2

3S1-ByteT1C

0 (lowest)SECinternal

2 *S1-ByteT1B

1 (highest)S1-ByteT1A

PriorityQuality

*

*

*

* : Selected Clock, selection via Quality and Priority

S1:Don‘t use

S1:SEC

S1:PRCS1:PRC

S1:PRC

S1:PRC

PDH: 2 Mbit/s

2 MHz signal, external clock

T1A

T1B

T1C

T2

T3

S1:PRC

S1:PRC T1S1:Don‘t use

T2

S1:PRC T1

T1(PRC)

SEC

NE A

SEC

NE B

SEC

NE C

� Selection criteria:� SSM indicates quality level (QL) of each T1 reference.� priority table: each reference input is given a certain priority (by operator)

� If the SSM (Synchronization Status Message) is not managed, only the priority table is taken into account and the transmitted qualities have QL6: not to be used for synchronization.

� If a port is selected as the synchronization reference, its output carries an S1-byte whose quality is QL6: value is ‘1111’ (don’t use) to avoid sync loops.

� Quality Levels:

S1-byte Clock� QL2: 0000 --- � Quality unknown (invalid) � QL1: 0010 PRC � STM-N signals with a G.811 source� QL3: 0100 SSU-Transit � STM-N signals with a G.812T source� QL4: 1000 SSU-Local � STM-N signals with a G.812L source� QL5: 1011 SEC � STM-N signals with a G.813 source� QL6: 1111 --- � Not to be used for synchronization


11.8

11 Network SynchronisationLinear Networks without SSM

Without faults

W E W E W E

Incorrect

Sync loop

W E

Correct

Equipment in holdover mode

W

W

W W

W

E E E

E E

� Correct NE configuration / Without faults:In a linear network, all NE extract their synchronization from the West (or East) STM and switch to holdover mode if the link is lost (no sync loops).

� Incorrect NE configuration:T1 from W, priority 1T1 from E, priority 2 : Sync-loops in case of failure

� Ring Networks without SSM: see Appendix B1


11.9

11 Network SynchronisationLinear Networks with SSM

EPRC

WE

1111

PRCWE

1111

PRCW

1111

phase 1

E

WE

SECWE

1111

PRCW

1111

phase 2

E

WE

SECWE

1111

SECW

1111

phase 4

E

WE

SECWE

1111

SECW

SSU

phase 5

ESSU

WE

SSUWE

1111

SSUW

1111

phase 7

PRCPRC PRC PRC

SEC SEC SEC

PRC

Equipment in holdover mode

1

2

3

1

2

3

1

2

3

1

2

3

1

2

3

4 4444

SSU SSU SSUSSU SSU

� Initially W (West) ports have the highest quality level

� Configuration of Network elements:

� Ring Networks with SSM: see appendix B2

SSU2T3 from SSU

S1-Byte1T1 from W4

S1-Byte1T1 from W2...3

S1-Byte2T1 from E

S1-Byte2T1 from E

PRC1T3 from PRC1

Quality Level

Priosynchronization source,reference input taken from

NE


11.10



11 Network Synchronisation Evaluation

� Objective: to be able to describe the principles of synchronisation of SDH networks



12 Optical Interfaces


12.2

12 Optical InterfacesSession presentation

� Objective: to be able to list the optical interfaces used in SDH

� program:

� 12.1 Classification of Optical Interfaces

� 12.2 Laser Safety

� 12.3 Automatic laser Shutdown : ALS

� 12.4 Laser Operation Actions


12.3

12 Optical InterfacesClassification of Optical Interfaces

Application

Rated source wavelength (nm)

Fiber typerecommendation

Distance (max. km)

STM level

STM-1

STM-4

STM-16

STM-64

Intra-station

1310

G.652

< 2

Inter-station

1310

G.652

Short-haul

1550

G.652

~ 15

Long-haul

1310

G.652

~ 40

G.652G.654

1550

G.653

~ 80

Joint Engineering

1550

~ 90

I-1

I-4

I-16

I-64

S-1.1

S-4.1

S-16.1

S-64.1

S.1-2

S.4-2

S.16-2

S.64-2

L-1.1

L-4.1

L-16.1

L-64.1

L-1.2

L-4.2

L-16.2

L-64.2

L-1.3

L-4.3

L-16.3

L-64.3

L-1.2 JE

L-4.2 JE

L-16.2 JE

L-64.2 JE

� Classification of optical interfaces according to G .957

� Application code: X-Y.ZX: Application I, S, LY: STM level 1, 4, 16, 64Z: Suffix number1 or blank: 1310 nm (G.652)

2: 1550 nm (G.652 / G.654) 3: 1550 nm (G.653)

� Three main application categories:� Intra-station (I): distances of less than approximately 2 km� Inter-station (S: Short-haul): distances of approximately 15 km� Inter-station (L: Long-haul): distances of approximately 40 km with 1310 nm

distances of approximately 80 km with 1550 nm

� If these categories are inadequate, Inter-station Joint Engineering (JE) shall be used: distances of approximately 90 km with 1550 nm

� The distances are used for classification and NOT specification purposes.


12.4

12 Optical InterfacesLaser Safety

Laser classifications complying with IEC 69825-2

Board Application Code Hazard Level Laser Classification

complying with ITU-T REC. G.957 complying with IEC 60825-2 complying with IEC 60825-1

STM-1 optical S-1.1 (Short Haul 1310 nm) 1 1L-1.1 (Long Haul 1310 nm) 1 3A

STM-16 S-16.1 (Short Haul 1310 nm) 1 3AL-16.1 (Long Haul 1310 nm) 1 3AL-16.2 (Long Haul 1550 nm) 1 3AL-16.2JE1 (Long Haul 1550 nm) 1 3AL-16.2JE2 (Long Haul 1550 nm) 1 3A

OA: Optical Amplifier OA-10 / OA-13 / OA-15 1 (if ALS is activated) 3A

Hazard level limits for single mode fibers with 11 µm mode field diameter

Wavelength Hazard Level 1 Hazard Level 3A

1310 nm 8.85 mW (+9.5 dBm) 24 mW (+13.8 dBm)

1550 nm 10 mW (+10 dBm) 50 mW (+17 dBm)

� They might be different from laser classifications complying with IEC 60825-1:The reason is that hazard levels are assigned under consideration of reasonable events whereas laser classification is made under consideration of one single fault.

� The optical transmitters and amplifiers used in the system emit optical power in the invisible infra-red spectrum range. Under normal operating conditions, the optical power is transferred in the fibers and is not accessible. The hazard levels of optical transmitters and optical amplifiers in the system are classified according to IEC 60825-1, without optical fibers connected to the output and taking one single component failure into account.

� X dBm = 10 x/10 mW� 0 dBm = 1 mW


12.5

12 Optical InterfacesAutomatic Laser Shutdown: ALS

NE 1Port A

NE 2Port B

Laser1

Laser2

Cutoff

A.L.S.command

A.L.S.command

LOS 2

LOS 1

� ALS: Automatic Laser Shutdown

� A cut-off which triggers a Loss of Signal (LOS) causes the laser in the opposite direction to be turned off automatically.

� Timing:1. cut-off2. LOS 1 (detected in NE2) 3. ALS (command sent to Laser2 in NE2)4. LOS 2 (detected in NE1)5. ALS (command sent to Laser1 in NE1)


12.6

12 Optical InterfacesLaser restart management

Laser inoperation for(90 ± 10) s

Start

Section innormal operation

ALS in service

Signal received from remote end ?

Loss of transmittedsignal for

t > = (550 ± 50) ms ?

Automatic laser shutdown

AutomaticRestart

Manualrestart

Manual restartfor testing

Timeout(60-300)s

Laser inoperation for(2 ± 0.25) s

Yes

No

Yes

No

Laser inoperation for(2 ± 0.25) s

� The following working practices are strongly recomm ended:� Where possible, optical transmission or test equipment should be shut down, put into a low power state or disconnected

before any work is started on exposed fiber, connectors, etc.� Check the optical power in a fiber only by using a calibrated optical power meter.� Do not stare directly into the beam or use any unapproved collimating device to view the fiber ends or connector faces or

point them at other people.� Use only approved filtered or attenuating viewing aids.� Any single or multiple fiber ends or ends found not to be terminated shall be individually or collectively covered when not

being worked on.They shall not be readily visible and sharp ends shall not be exposed.

� Always attach end caps to unmated connectors.� When using optical test cords, the optical power source shall be the last to be connected and the first to be disconnected.� Do not make any unauthorized modifications to any optical fiber system or associated equipment.� Replace damaged optical safety labels or attach new labels if labels are missing.� Use test equipment of the lowest class necessary and practical for the task. � Do not use test equipment of a higher class than the location hazard level.


12.7



12 Optical Interfaces Evaluation

� Objective: to be able to list the optical interfaces used in SDH



13 Appendices


List of abbreviations

ADM Add-Drop Multiplexer (NE)AI Adapted InformationAIS Alarm Indication SignalALS Automatic Laser ShutdownAP Access PointAPS Automatic Protection SwitchingATM Asynchronous Transfer ModeAU Administrative UnitAU-n Administrative Unit, level n (n = 3, 4)AUG Administrative Unit Group

BBE Background Block ErrorBBER Background Block Error RatioBER Bit Error RatioBIP Bit Interleaved Parity

C-n Container, level n (n= 11, 12, 2, 3, 4)CI Characteristic InformationCMI Coded Mark Inverted (electrical signal, G.783)CP Connection PointCT Craft TerminalCTP Connection Termination Point

DCC Data Communication ChannelDCN Data Communication NetworkDEC DecrementDEG DegradedDQDB Distributed Queue Dual BusDXC Digital Cross-Connect (NE)

E0 Electrical interface signal 64 kbit/sE11/ E12 Electrical interface signal 1544 / 2048 kbit/s E22 Electrical interface signal 8448 kbit/sE31/ E32 Electrical interface signal 34368 / 44736 kbit/sE4 Electrical interface signal 139264 kbit/sEB Errored BlockE-BER Excessive Bit Error Ratio

ECC Embedded Communication Channel

EOW Engineering Order Wire

EPS Equipment Protection Switching

EQ Equipment

Eq G.703 type electrical signal, bit rate order q (q=11,12,21,22,31,32,4)

ES Errored SecondES Electrical SectionESR Error Second RatioETSI European Telecommunication Standard InstituteETX Electrical Transmit



FAW Frame Alignment WordF_B Far-end BlockF_DS Far-end Defect SecondF_EBC Far-end Errored Block CountFEBE Far End Block Error (now REI)FERF Far End Receive Failure (now RDI)FDDI Fibre Distributed Data IntFM Fault Management

G.abc Recommendation abc according ITU-T

HCS Higher order Connection SupervisionHDLC High level Data Link ControlHO Higher OrderHOA Higher Order AssemblerHOI Higher Order InterfaceHOP High Order PathHOPA High Order Path AdaptationHOPT High Order Path TerminationHOVC Higher Order Virtual ContainerHP Higher order PathHPA Higher order Path AdaptationHPC Higher order Path ConnectionHPI Higher order Path termination InterfaceHPOM Higher order Path Overhead MonitorHPP Higher order Path ProtectionHPT Higher order Path Termination HSUT Higher order path Supervisory Unequipped TerminationHTCA Higher order path Tandem Connection AdaptationHTCM Higher order path Tandem Connection MonitorHTCT Higher order path Tandem Connection TerminationHUG Higher order path Unequipped Generator

ID IDentifierINC INCrementIP Internet ProtocolISO International Standards OrganizationITU-T International Telecommunication Union - Telecommunication sector

JE Joint EngineeringLASER Light Amplification by Stimulated Emission of RadiationLC Link ConnectionLED Light Emitting DiodeLO Lower OrderLOF Loss Of FrameLOM Loss Of MultiframeLOP Loss Of PointerLOP Low Order Path LOPA Low Order Path AdaptationLOPT Low Order Path TerminationLOS Loss Of SignalLOVC Lower Order Virtual ContainerLP Lower order PathLPA Lower order Path Adaptation



LPC Lower order Path ConnectionLPOM Lower order Path Overhead MonitorLPP Lower order Path ProtectionLPT Lower order Path TerminationLSUT Lower order path Supervisory Unequipped TerminationLTCA Lower order path Tandem Connection AdaptationLTCT Lower order path Tandem Connection TerminationLTCM Lower order path Tandem Connection MonitorLUG Lower order Unequipped Generator

MAN Metropolitan Area NetworkMSA Multiplex Section AdaptationMS-AIS Multiplex Section Alarm Indication SignalMS-FERF Multiplex Section Far End Receive FailureMSN Multiple Service Node (NE)MSn Multiplex Section layer, level n (n=1, 4, 16, 64)MSOH Multiplex Section OverHeadMSP Multiplex Section ProtectionMS-RDI Multiplex Section Remote Defect IndicationMS-REI Multiplex Section Remote Error IndicationMS-SPRING Multiplex Section Shared Protection in a RingMST Multiplex Section Termination

NA Not ApplicableNC Network ConnectionNDF New Data FlagNE Network ElementNPI Null Pointer IndicationNRZ Non Return to Zero (optical signal, G.783)NSAP Network Service Access PointNU National Use

OAB Optical Amplifier Board OAM&P Operations, Administration, Maintenance and ProvisioningOAM Operations, Administration, and MaintenanceOFS Out of Frame SecondOOF Out Of FrameORX Optical ReceiverOS Operation SystemOSn Optical Section layer, level n (n=1, 4, 16, 64)OSI Open Systems InterconnectionOTx Optical TransmitOW Order Wire

P-AIS Path Alarm Indication SignalP0x 64 kbit/s layer (transparent)P11x / P12x 1544 / 2048 kbit/s layer (transparent)P12s 2048 kbit/s PDH path layer with synchronous 125µs frame structure P21x/P22x 6312 / 8448 kbit/s layer (transparent)P22e 8448 kbit/s PDH path layer with 4 plesiochronous 2048 kbit/s



P31e 34368 kbit/s PDH path layer with 4 plesiochronous 8448 kbit/sP31s 34368 kbit/s PDH path layer with synchronous 125µs frame structure P31x/P32x 34368 / 44736 kbit/s layer (transparent)P4a 139264 kbit/s PDH path layer with 3 plesiochronous 44736 kbit/sP4e 139264 kbit/s PDH path layer with 4 plesiochronous 34368 kbit/sP4s 139264 kbit/s PDH path layer with synch. 125µs frame structure P4x 139264 kbit/s layer (transparent)PDH Plesiochronous Digital HierarchyPI Physical InterfacePJ Pointer JustificationPLL Phase Lock LoopPLM Payload Label Mismatch (= SLM)PM Performance MonitoringPOH Path OverHeadPPI Plesiochronous Physical InterfacePPS Path Protection Switching (SNCP)Pq Plesiochronous path layer, bit rate order q (q=11, 12, 21, 22, 31, 32, 4)PRC Primary Reference ClockPTR PoinTeR

QECC Embedded Control ChannelQL Quality Level

RDI Remote Defect Indication (former FERF)REI Remote Error Indication (former FEBE)RM Regional ManagerRSn Regenerator Section layer, level n (n=1, 4, 16, 64)RSOH Regenerator Section OverHeadRST Regenerator Section TerminationRxSL Received Signal LabelRxTI Received Trace Identifier

S11/S12 VC-11 / VC-12 path layerS11D/S12D VC-11 / VC-12 tandem connection sub-layerS11P/S12D VC-11 / VC-12 path protection sub-layerS2 / S3 / S4 VC-2 / VC-3 / VC-4 path layerS2D / S3D VC-2 / VC-3 tandem connection sub-layerS2P/S3P/S4P VC-2 / VC-3 path Protection sub-layerS3T / S4T VC-3 / VC-4 tandem connection sub-layer using TCM definition according annex C/G.707 (option 1)S4D VC-4 tandem connection sub-layer using TCM definition according annex D/G.707 (option 2) SA Section AdaptationSD Signal DegradeSDH Synchronous Digital HierarchySEC Synchronous Equipment ClockSEMF Synchronous Equipment Management FunctionSES Severely Errored SecondSETG Synchronous Equipment Timing GeneratorSETPI Synchronous Equipment Timing Physical InterfaceSETS Synchronous Equipment Timing SourceSF Signal FailureSLM Signal Label Mismatch (= PLM)



Sm lower order VC-m layer (m=11, 12, 2, 3)SmD VC-m (m=11, 12, 2, 3) tandem connection sub-layerSmm VC-m (m=11, 12, 2, 3) path layer non-intrusive monitorSmP VC-m (m=11, 12, 2, 3) path protection sub-layerSms VC-m (m=11, 12, 2, 3) path layer supervisory-unequippedSMN SDH Management NetworkSMS SDH Management Sub-networkSn higher order VC-n layer (n=3, 4)SnD VC-n layer (n=3, 4) tandem connection sub-layer using TCM definition according annex G.707Snm VC-n (n=3, 4) path layer non-intrusive monitorSnp VC-n (n=3, 4) path protection sub-layerSns VC-n (n=3, 4) path layer supervisory-unequippedSnT VC-n (n=3, 4) tandem connection sub-layer using TCM definition according annex G.707SNCP Sub Network Connection Protection (PPS)SNCP/I Sub Network Connection Protection with Inherent MonitoringSNCP/N Sub Network Connection Protection with Non-intrusive monitoringSOH Section OverHeadSONET Synchronous Optical NETwork SPI Synchronous Physical Interface SSD Server Signal DegradeSSF Server Signal FailSSM Synchronization Status MessageSSU Synchronization Supply UnitST Section TerminationSTM-N Synchronous Transport Module N (N*155 Mbit/s, N= 1, 4, 16, 64)STS Synchronous Transport Signal (SONET levels)

TCM Tandem Connection MonitorTCP Termination Connection PointTI Timing InformationTIF Timing Input FailTIM Trace Identifier MismatchTMN Telecommunication Management NetworkTP Timing PointTP Termination PointTT Trail Termination functionTTF Transport Terminal FunctionTTI Trail Trace IdentifierTTP Trail Termination PointTU-n Tributary Unit, level n (n= 11, 12, 2, 3)TUG-k Tributary Unit Group, level k (k= 2, 3)TxSL Transmitted Signal LabelTxTI Transmitted Trace Identifier

UAS UnAvailable SecondUAT UnAvailable TimeUNEQ UNEQuipped (signal)

VC-n Virtual Container, level n (n= 11, 12, 2, 3, 4)VC-n-Xc Concatenation of X virtual containers of level n

WDM Wavelength Division Multiplexer (NE)


13.7

Appendix A1 Management Hierarchy

SML

NML

EML

ECT

ELDXC

SDH NE Manager

WDM Microwave Submarine

CT CT CT CT

SDH Network Manager

Service Manager

CT

ADM

� EL: Element Layer� All the different kinds of Network Elements (NE) are located in this layer

� ECT: Equipment Craft Terminal� All different kinds of Network Elements can be managed locally, depending on the type of NE and the type of local

management interface operation.

� EML: Element Management Layer� Handles the physical configuration of the network resources� Collects and processes the alarms emitted by the NEs to inform the operator� Collects performance data of the NEs to allow preventive maintenance� Ensures the availability of the network resources

� NML: Network Management Layer� Sets up end-to-end paths using the network resources available � Optimizes the use of the network resources� Correlates performance data to paths and provides statistics of the quality to paths.

� SML: Service Management Layer� Handles the setup of services in the network and ensures their availability


13.8

Appendix A2 SDH-SONET Compatibility

4 x 9 bytes

STM-4resp.

STS-12

9 bytes

STM-1

SDH

Plesiochronous origin signals(European standard)

3 x 3 bytes

STS-3

STS-1 STS-1STS-1

synchronous

Plesiochronous origin signals

(US standard)

155.52 Mbit/s

51.84 Mbit/s(STM-0)

622.08 Mbit/s

SONET

Same frame structure

STS-12

� Low-or medium-rate systems using radio or satellite technologies in the SDH hierarchy have not been designed to use STM-1 signals:They operate with a 51.840 Mbit/s binary rate: STM-0

� SONET: Synchronous Optical NETwork

� SDH: Synchronous Digital Hierarchy

� STS: Synchronous Transport Signal (SONET levels)

� STM: Synchronous Transport Module (SDH levels)

9953.280STM-64STS192

2488.320STM-162488.320STS-48

622.080STM-4622.080STS-12

466.560STS-9

155.520STM-1155.520STS-3

51.84STM-051.840STS-1

RATE (Mbit/s)SDH FRAMERATE (Mbit/s)SONET FRAME


13.9

Appendix A2 SDH-SONET Compatibility (continuation

RSOH

MSOH

SOH

LineOH

Pointer

3 bytes

Section overhead : byte assignment

9 ro

ws

#1

#3

#2 STS-1

A1 A1 A1 A2 A2 A2 J0 X X

D1 D D D2 D D3

AU-4 Pointer

B2 B2 B2 K1 K2

D4 D5 D6

D7 D8 D9

D10 D11 D12

S1 Z1 Z1 Z2 Z2 M1 E2 X X

A1 A2

B1 E1

D1 D2

H1 H2

C1

F1

D3

H3

B2 K1

D4 D5

D7 D8

D10 D11

K2

D6

D9

D12

Z1 Z2 E2

A1

B1

D1

H1

B2

D4

D7

D10

Z1

A1

B1

D1

H1

B2

D4

D7

D10

Z1

A1

B1

D1

H1

B2

D4

D7

D10

Z1

A2

E1

D2

H2

K1

D5

D8

D11

Z2

A2

E1

D2

H2

K1

D5

D8

D11

Z2

A2

E1

D2

H2

K1

D5

D8

D11

Z2

C1

F1

D3

H3

K2

D6

D9

D12

E2

C1

F1

D3

H3

K2

D6

D9

D12

E2

C1

F1

D3

H3

K2

D6

D9

D12

E2

9 bytes9 bytes

B1 D D E1 D F1 X X


13.10

Appendix A3 STM-0 Interface at 51.840 Mbit/s, Frame Structure

A1 A2

B1 E1

D1 D2

H1 H2

C1

F1

D3

H3

B2 K1

D4 D5

D7 D8

D10 D11

K2

D6

D9

D12

S1 M1 E2

J1

B3

C2

G1

F2

H4

F3

K3

N1

1 901

9

STM-0 Frame

VC-3

fixed

stu

ff

fixed

stu

ff

29 30 31 58 59 60

VC-3 POH


13.11

Appendix B1 Ring Networks without SSM

6 5 4

1 2 3

Switch to holdover mode

6 5 4

1 2 3

holdover

6 5 4

1 2 3

Sync loop

6 5 4

Switch to holdover mode

6 5 4

1 2 3No fault

Sync loop

Incorrect

Correct

Incorrect

Correct

Reference fault

Path fault

� Correct / No fault� NE1 configuration: T3 (from PRC), priority 1

no second reference� NE other configuration: T1 from W, priority 1

no second reference

� Incorrect� NE1 configuration: T3 (from PRC), priority 1

T1 from E, priority 2� NE other configuration: T1 from W, priority 1

T1 from E, priority 2: sync loops in case of line failureor PRC failure

� No SSU available


13.12

Appendix B2 Ring Networks with SSM

6 5 4

1 2 3

holdover

6 5 4

1 2 3

holdover

6 5 4

1 2 3

holdover

6 5 4

1 2 3

PRC

6 5 4

PRC

PRC

"1111"

PRC

"1111""1111" "1111"

PRC PRCPRC

PRC

PRC

"1111"

SEC

"1111"

PRC

SEC

"1111"

SEC

"1111"

PRC PRC

PRC

SEC

PRC

SEC

"1111"

PRC PRC

"1111"

"1111" "1111""1111"

PRC PRC PRCPRC

PRC

PRC

PRC

PRC

"1111"

"1111"

PRC

W E W E W E

WE WEW E

"1111"

"1111" "1111"

"1111"

PRC

"1111""1111"

PRC

phase 5

phase 4

phase 3

phase 2

phase 1

� Initially W (West) ports have the highest quality level

� No SSU available

� Configuration of Network elements:

S1-Byte2T1 from E

S1-Byte1T1 from W2...6

PCR1T3 (PCR)1

Quality Level

PrioSynchronization sourcereference input take from

NE


13.13

Appendix C1 Example of Layering in RM Systems


13.14

Appendix C2 Functional Model G.805

Application of the functional architecture of the case of PDH supported on SDH

AP Access PointCP Connection PointTCP Termination Connection PointIOST Intra-Office section terminationIOSA Intra-Office section adaptation

LOP Lower-order path e.g. VC-12LOPA Lower-order path adaptationLOPT Lower-order path terminationLOPSN Lower-order path sub-network

HOP Higher-order path e.g. VC-4 HOPA Higher-order path adaptation HOPT Higher-order path termination HOPSN Higher-order path sub-networkSA STM-N section adaptationST STM-N section termination

G.702path link

connection

G.702path link

connectionG.702 path link connection

LOP trail

LOP linkconnection LOP link connection

HOP trail

HOP linkconnection

HOP linkconnection

HOP trail

HOP linkconnection

STM-Nsection trail

STM-Nsection trail

STM-Nsection trail

STM-N sectionlink connection



LOPSNconnection

HOPSNconnection

LOPSN

HOPSN

intra-officesection trail

intra-officesection trail

IOST IOST

G.703interface

G.703interface

IOSA IOSALOPA LOPA

HOPA HOPA

SA SA

LOPT LOPT

HOPT HOPT

ST ST

APAP

APAP

APAP

TCPTCP

TCPTCP

TCPTCP TCPTCP

AP AP

TCPTCP

AP AP

TCPTCP

HOPA HOPA

HOPT HOPT

ST ST

SA SA SA SAAP APST ST

TCPTCP


� Appendix C3 General Functional Block Diagram G.783

SmsSmsSmmSmDmSmDSmD

SmD/Sm

Sm

Sn

RSn

MSn

MSn MSn

ESl/RSl ESl/RSl

ESl ESl

ESl

OSn/RSn OSn/RSn

OSn OSn

OSn

Sn Sn

Sm Sm

SnDmSnDSnD

SnSSnsSnmSnD/Sn SnD/Sn

Sm/Pqx Sm/Pqs Sm/Pqx Sm/PqsTO_TP

SmD/Sm

Sn/Sm Sn/Pqx Sn/User Sn/Sm Sn/Pqx Sn/User

RSn/DCC RSn/OW RSn/SD RSn/Sn RSn/Sn RSn/SD RSn/OW RSn/DCC

RSn RSn

SDH physical layers

Regenerator section layer

Multiplex section layer

Higher orderpath layer

Lower orderpath layer

Ppx_CP Pps_CP Ppx_CP Pps_CP

SmD_AP

Sm_RISm_RI Sm_RITSF

SD

TSFTSD

TSFTSD

SnD_AP

Sn_RISn_RI Sn_RITSF

SD

TSFTSD

TSFTSD

Ppx_CP User_CP Ppx_CP User_CPSm_CP Sm_CP

Sn_CPSn_CPD4-D12 E2 S1[5-8] S1[5-8] E2 D4-D12

MSn_RI

MSn_CPMSn_CPD1-D3 E1 F1 F1 E1 D1-D3

MSn/DCC MSn/OW MSn/SD MSn/Sn MSn/Sn MSn/SD MSn/OW MSn/DCC

OSn_CP ESl_CP


13.16

Appendix D ITU-T recommendations

G.652 Characteristics of a single-mode optical fiber cable

G.653 Characteristics of a dispersion-shifted single-mode optical fiber cable

G.654 Characteristics of a cut-off shifted single-mode optical fiber cable

G.702 Digital hierarchy bit rates

G.703 Physical/electrical characteristics of hierarchical digital interfaces

G.707 Synchronous Digital Hierarchy bit rates

G.783 Characteristics of Synchronous Digital Hierarchy multiplexing equipment

G.805 Generic functional architecture of transport networks

G.811 Timing characteristics of primary reference clocks

G.812 Timing requirements of slave clocks suitable for use as node clocks in

synchronization networks

G.813 Timing characteristics of SDH equipment slave clocks (SEC)

G.826 Error performance parameters and objectives for international, constant bit rate digital paths at or above the primary rate (Performance Monitoring)

G.957 Optical interfaces for equipment and systems relating to the synchronous digital hierarchy


� Appendix E Alarm scheme

MST

OOF

RDIREIRST

SPI

TUUNEQ

VC

Administration Unit

Higher Order Virtual ContainerHigher Order PathHigher Order Path AdaptionHigher Order Path ConnectionHigher Order Path Overhead

MonitorHigher Order Path Termination

Higher Order SupervisoryUnequipped Generator

Loss of FrameLoss of MultiframeLoss of PointerLoss of SignalLower Order Virtual Container

Lower Order PathLower Order Path AdaptionLower Order Path ConnectionLower Order Path Overhead

MonitorLower Order Path TerminationLower Order SupervisoryUnequipped Generator

Multiplex Section AdaptionMultiplex Section Termination

Out of Frame

Remote Defect Indication (FERF)Remote Error Indication (FEBE)Regenerator Section Termination

PTM Path Trace Mismatch

Physical Section Interface

-

PLTM Payload Type Mismatch

Tributary UnitUnequipped Signal per G.709

Virtual Container

LOS - %LOF - %OOF W -B1 errors W -

MS-AIS W %B2 errors W %MS-RDI W %MS-REI W -

AU-AIS - %AU-LOP - %

HP-UNEQ - -HP- PTM W %HP- PLTM W %B3 errors W %HP-RDI W %HP-REI W -

TU-AIS - %HP-LOM - -HP-LOP - %

LP-UNEQ - -LP-TIM W %LP-SLM W %LP-BIP errorsLP-RDI W %LP-REI W -

forward direction backward direction

"1"

"1"

"1"

”1"

"1"

"1"

"1"

SPI RST MST MSA HPOM/HSUT HPC HPT HPA LPOM/LSUT LPC LPT(no system clock) SSF

LOS

LOF

RS- BIP Error (B1)

Regenerated signalpassed through

SSF

(K2)

(B2)

(B2)

(M1)

(K2)

(M1)

MS-AIS

(K2)

MS-Exc. Error.

MS-DS

MS-REI

MS-RDI

MS-RDI

MS-REI

AU-AIS

HP-REI

HP-RDI

HP-RDI

HP-REI

TU-AIS SSF

HP-LOM/TU -LOP Unused LPCOutput

LP -UNEQLO path signal passed through

LOVC with POH and unspecified payload signal

LO unequipped signal

(G1)

(G1)

(G1)

(G1)

(J2)

(V5)

(V5)

(V5)

(V5)

(V5)

(V5)

LP- UNEQ

LP- PTM

LP- PLTM

LP-DS

LP- REI

LP- RDI

DetectionGenerationInsertion of all ones (AIS) Signal

AU

HOVCHPHPAHPCHPOM

HPTHSUT

LOFLOMLOPLOSLOVCLPLPALPCLPOM

LPTLSUT

MSA

"1"

"1"

"1"

AU-AIS

AU-LOP

SSF

Unused HPCOutput

HP-UNEQ

HO path signal passed through

HOVC with POH and unequipped payload signal

HO unequipped signal

HP-UNEQ

HP-PTM

HP-PLTM

TU-AIS

(J1)

(C2)

LPA

W %

HP-DS(B3)

optional

SSF Server Signal Fail

Degraded SignalDS

HP-Exc. Error(B3)

(V5) LP-Exc. Error

LP- RDI

LP- REI

fundamentals of sdh

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