7-SDH & MSTP Principle

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SDH & MSTP principleV0501

ZTE university

Course manager：Yuan ling

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Course contents：

•SDH system overview

•EOS principle




SDH system overviewPlesiochronousPlesiochronous digital hierarchy (PDH)digital hierarchy (PDH)

400Mb/s

100Mb/s

32Mb/s

6.3Mb/s

Japan system

274Mb/s

45Mb/s

6.3Mb/s

565Mb/s

139Mb/s

34Mb/s

8Mb/s

2 Mb/s1.5Mb/s

North Americasystem

Europe system

×4×4

×4

×4

×4

×4

×3

×5

×6

×7

×4

1.5Mb/s




SDH system overview

Adding and dropping 2M signal in PDHAdding and dropping 2M signal in PDH

140/34M bit/s 34/140M bit/s

O / E

Optical

interface

dropping

dropping

dropping

adding

adding

adding

E / O

PDH

34/8M bit/s 8/ 34M bit/s

8/2M bit/s 2/ 8M bit/s

2M bit/s

Optical

interface




Directly adding and dropping of 2M in SDH

SDH system overview

ADMADM155MBIT/S 155MBIT/S

2M 2M




SDH system overview

SDH feature

•• SDH unifies the main three digital system of the world, and it iSDH unifies the main three digital system of the world, and it is s entirely compatible with PDH.entirely compatible with PDH.

•• Support standard optical interface.Support standard optical interface.

•• Easy adding and dropping of 2M service.Easy adding and dropping of 2M service.

•• Rich overhead bytes for operation, management and maintenance.Rich overhead bytes for operation, management and maintenance.




SDH system overview

level STM-1 STM-4 STM-16 STM-64rate（Mbit/s） 155.520 622.080 2488.320 9953.280

SDH has a set of standard information structure level, and they are synchronous transmission module STM-1,STM-4,STM-16，which have leaf-like frame structure.

Rate level of SDHRate level of SDH




MSOH

RSOH

Frame structure of STMFrame structure of STM--NN1 frame

9×270×N bytes

1345

9 9 × N 261 × N270 × N

Segment overhead refers to the additional bytes necessarily required to ensure the normal and flexible transmission of information payload in the STM frame structure.Segment overhead consists of two parts: RSOH(regeneration SOH) and MSOH(multiplexing SOH).

•RSOH manages the regeneration segment.AU PTR is an indicator, used mainly to indicate the accurate position of the 1st byte of the information payload in the STM-N frame so that it is correctly dissolved at the receiving end.

•MSOH manages the multiplexing segment made up of several regeneration segment.

•information payload area is the place for storing various information capacities in the frame structure.•Information payload includes path overhead(POH).

RSOH

MSOH

•STM-1 frame is made up of 9 rows and 270 columns, and there are totally 2430 bytes. The transmission sequence is from left to right and from up to down. Every second 8000 frame will be transmitted.•The transmission rate is: 270×9×8×8000=155.520Mbit/s

STM-N payload

（including POH）AU PTRAU PTR

RSOH

MSOH

Transmissiondirection




SDH system overview

RSOH

MSOHSOH

POH

SDH OverHead

OverHeadHD POH

LD POH




SDH system overview

A1A1 A1A1 A1A1 A2A2 A2A2 A2A2 J0J0 **×× **××××××F1F1E1E1△△B1B1

D1D1

K2K2K1K1B2B2

××××E2E2M1M1S1S1

AUAU PTRPTR

△△

△△△△

△△

△△

B2B2 B2B2

D2D2 D3D3

D4D4D7D7D10D10

D5D5

D10D10 D11D11D8D8 D9D9

D6D6

D12D12

1 2 3

123456789

4 5 6 7 8 9

Arrangement of the SOH bytes in STMArrangement of the SOH bytes in STM--11




SDH system overview1) Frame alignment bytes: A1, A2. They are used to

identify the start position of a frame. A1, A2 have definite binary numerical values: A1 is 11110110; A2 is 00101000.

2) Regenerator section trace byte: J0. This byte is used to send the “Section Access Point ID ” repeatedly, so that the section receiver can determine whether the connection between the receive end and the preset transmit end is in a continuously connected status.

3) Bit interleaved parity 8 code (BIP-8 code) byte: B1. It is used to monitor the bit error of the RSOH.

R

S

O

H




SDH system overview

4) Orderwire bytes: E1. It belongs to the RSOH, and is used to provide an orderwire communication voice channel. The orderwire channel rate is 64Kbit/s.

5) User channel byte: F1. This byte is reserved specially for the user (often referring to the network provider). It provides temporary data/voice channel connection or special maintenance purposes.

6) Data communication channel (DCC) bytes: D1, D2, D3.They can be used to form the transmission link of the SDH Management Network.




M

S

O

H

SDH system overview

1) BIP-NX24: B2. It is used to monitor the bit error of the multiplexing section.

2) Data communication channel (DCC) bytes: D4~D12. They are used to form the transmission link of the SDH Management Network for MSOH.

3) Orderwire bytes: E2. It belongs to MSOH, and is used to provide an orderwire communication voice channel.




SDH system overview4) Automatic protection switch (APS) channel bytes: K1

and K2 (b1-b5). The two bytes serves as APS signaling (commands).

5) Mutiplexer section-Remote Defect Indication (MS-RDI):K2 (b6-b8). This byte is used to return an indication to the transmit end, indication that the receive end has detected upstream section failure or received MS-AIS (Multiplexer Section-Alarm Indication Signal). MS-RDI is expressed by setting b6, b7 and b8 of the unscrambled K2 byte to “110”.




SDH system overview

6) Synchronous status byte: S1 (b5-b8).

7) Mutiplexer section-Remote Error Indication (MS-REI): M1. This byte transfers the number of interleaved bit blocks of errors detected by the B2 (0-255).




SDH system overview

Multiplexing principle introduction

1. Several important concepts;

2. Mapping, Alignment and Multiplexing process.




Container

SDH system overview

• Container is a kind of information structure. Its main function is adaptation(rate adjustment). All the common PDH system signals can be contained in several standard containers.

• ITU-T recommended 5 standard containers:C-11、C-12、C-2、C-3 and C-4.




SDH system overviewVirtual container

• Virtual container is another information structure which is almost the most important in SDH system.

• Virtual container consists of two parts:the signal from container and low level POH.




SDH system overview

Tributary unit and administration unit• TU is made up of low level VC and TU PTR. It is a

information structure which supplies the adaptation function between the low level channel layer and high level channel layer.

• AU is made up of high level VC and AU PTR. It is a information structure which supplies the adaptation function between the high level channel layer and multiplexing segment layer.

• PTR is used to indicate the starting location of VC in TU or in STM-N frame. But the location of pointer itself is fixed.




SDH system overviewMapping

• The process of putting various tributary signal from containers into related virtual containers is called mapping.

• Its essence is to make the various tributary signals synchronized with related VC containers so that VC can be an independent entity in the transmission, multiplexing and

cross connection.




Multiplexing

SDH system overview

• The process of adapting multiple tributary units (TU-12 and TU-3) to the high level VC-4 or adapting multiple administration units to the multiplexing segment is called multiplexing.




SDH system overviewBasic process of mapping and multiplexingBasic process of mapping and multiplexing

Synchronous multiplexing

Insert pointer

Insert POH

Mapping intocontainer

VCTU或AU

High lever VC or STM-N

SDH tributary signal

Insert pointer

Insert POH

Mapping into container with rate adaptation

PDH tributary signal

C




SDH system overview

Mapping and multiplexing structure of SDHMapping and multiplexing structure of SDH

VC

STM-N× N × 1 140Mb/s

45Mb/s34Mb/s

6.3Mb/s

2Mb/s

1.5Mb/s

×3

×７

×７

×１×３

C-11

C-12

C-2

C-3

C-4

VC-11

VC-2

VC-3

VC-3

VC-4

TU-11

TU-12

TU-2

TU-3

TUG-2

TUG-3

AUG-4

AU-3

AU-4

VC-12×3

×4

×1

C

TU

AU

TUGAUG

STM-Ncalibrating

multiplexing

mapping




SDH system overviewMapping and multiplexing process

STM-N

× N × 1C-12VC-12VC-4 TUG-2AUG-4 AU-4 TU-12 2Mb/s

Rate adjustment

LD POHSOH AU PTR

×３multiplexing

×7 multiplexing

HD POH

×３multiplexing

×Nmultiplexing

TUG-3

TU PTR




SDH system overviewRate varying in multiplexing

The rate varying of 2M signal in multiplexingC-12=2M mapping=2.176

VC-12=C-12+LPOH=2.240

TU-12=VC-12+TU-PTR=2.304

TUG-2=3*TU-12=6.912

TUG-3=7*TUG-2+。。。=49.152

VC-4=3*TUG-3+HPOH=150.336

AU-4=VC-4+AU-PTR=150.912

AUG=AU-4=150.912

STM-N=N*（AUG+SOH）=N*155.520




EOS principle




EOS principle

1. EOS principle contents:

1) EOS system ;

2) Ethernet frame encapsulation;

3) Continuous cascade and virtual cascade;

4) EOS networking application.




EOS principle

EOS system




FramerFramer

L2 switch

SDH cross matrix

Ethernet transparently transmit

SDH

OL

SDH

OL

PDH/SDH interface、 PoS Ethernet interface（10M/100M/GE）

STM-N STM-N

EOS principleEOS system




EOS principle

VC

Mapping

VC

Mapping

M

S

O

H

M

S

O

H

R

S

O

H

R

S

O

H

STM－N

interface

STM－N

interface

EOS

Ethernet interface

L

2switching

PPP

/LAPS

/GFP

Assembly

Cross connection

EOS function module




EOS principle

Ethernet frame encapsulation




EOS principleEOS encapsulation protocol

IEEE 802.3 MAC

PPP/LAPS/GFP

VC12/VC3/VC4

Multiplex Section

Regeneration Section

PHY

Protocols:PPP、LAPS and GFP




EOS principle

Continuous cascade and virtual cascade




EOS principle

Continuous cascade

TDM

VC-4

VC-4

VC-4

VC-4

VC-4

VC-4

VC-4

VC-4

VC-4-4C VC-4-4C

IP TDM ATM

STM-16

IP/ATM TDM

VC-4-4C 4×VC-4STM-4

STMSTM--16 NE which supports VC16 NE which supports VC--4C function4C function




EOS principle

Virtual cacade

VC-12

VC-12

VC-12

VC-12

VC-12

VC-12-NC

Relay

SDH networkSDH network...

RX

TX




EOS principle

EOS networking application




EOS principle

Ethernet single board networking

Star networking:

1) Fit for trunking and centralized service;

2) Can supply bandwidth assurance;

3) High requirement for MSTP trunking port.




EOS principle

Link networking:

1) Fit for separated service, relay is serious;

2) Sharing bandwidth, has high usage, and is fit for the network which lack of optical line resource.

3) Need do the Cos configuration. When sharing the bandwidth, require high Qos ability.




EOS principle

Loop networking:1) Put STP in use, and avoid that logic topo

become to be loop;

2) In the condition that you don’t configure the physical protection, it still has the protection function;

3) Other features are same as link networking.Mixed networking:

According to the basic networking, do the network analysis.



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7-SDH & MSTP Principle