INTRODUCTION PDH & SDH On Job Training July 2006 PT Indonesia Comnets Plus.

INTRODUCTION PDH & SDH

On Job Training July 2006

PT Indonesia Comnets Plus

On Job Training, July 2006PT Indonesia Comnets Plus

Agenda

Pre SDH (PDH) SDH The SDH Frame Frame Structure

Overhead and Payload Analysis

Tributary Units SDH Network

Protection


Plesiochronous Digital Hierarchy

2 Mbps

8 Mbps

34 Mbps

140 Mbps

2 Mbps

8 Mbps

34 Mbps


Multiplexing hierarchy

The PDH high capacity transmission networks are based on a hierarchy of digital multiplexed signals: E.1 to E.4.

The basic building block is the primary rate of 2.048 Mb/s (E.1). This could be made up of 30 x 64 Kb/s voice channels. This would then be multiplexed up to a higher rate for high capacity transmisson.


Four signals at the primary rate can be multiplexed up to the secondary rate, E.2, of 8.448 Mb/s and so on up to a rate of 139 Mb/s (E.4).

Thus the 139 Mb/s rate represents 64 x 2.048 Mb/s signals and 1920 multiplexed voice channels.


Developing networks

The plesynchronous multiplexing technology, often called PDH (Plesiochronous Digital Hierarchy), left no room in the signal structures for network management and maintenance functions.

We are therefore left with no spare signal capacity to provide improvements in the signal transmission.


As networks developed inter-connection became increasingly complex. It required banks of multiplexers and large, unreliable distribution frames.

It became clear that the original standards, designed for point-to-point links, were just not suitable.



Tributary access We want to have easy access to an

individual tributary, in order that it may be re-routed.

We cannot do this without having to demultiplex the whole signal down to the required tributary level.

Costs go up as we demultiplex, and they then double because we have to re-multiplex the signal back up again.


No commont standard

Before SDH there were no standards to ensure that equipment from different vendors interworked on the same system.

Vendors can have their own unique designs which means we have to buy the same vendor’s equipment for both ends of the line.

Ideally we would like to shop around for the most suitable equipment, without having to keep to the same supplier.


What we need

Network operating companies have to provide faster, cost effective provisioning of customer circuits and services, as well as control of transmission bandwidth.


SDH Definition

SDH is a standard for ‘high speed – high capacity’ optical telecommunication networks ; more spesifically a synchronous digital hierarchy.

It is a synchronous digital transport system aimed at providing a more simple, economic and flexible telecommunications network infrastructure.


Advantages of SDH

Designed for cost effective, flexible telecoms networking – based on direct synchronous multiplexing.

Provides built-in signal capacity for advanced network management and maintenance capabilities.


Provides flexible signal transportation capabilities – designed for existing and future signals.

Allows a single telecommunication network infrastructure – interconnects network equipment from different vendors


Where is SDH used ?

SDH can be used in all of the traditional network application areas.

A single SDH network infrastructure is therefore possible which provides an efficient direct interconnection between the three major telecommunication networks.


Notes on SDH rates

The most common SDH line rates in use today are 155.52 Mbps, 622.08 Mbps, 2.5 Gbps, 10 Gbps.

SDH is a structure that is designed for the future, ensuring that higher line rates can be added when required.


SDH signal structure

The SDH signal is transported as a synchronous structure which comprises a set of 8-bit bytes organised into a two dimensional frame.

The ‘Truck analogy’ is a popular way to help us understand the contents of the SDH frame.


SDH FRAME STRUCTURETRUCK ANALOGY

Tractor

Unit

Payload

Unit


SDH FRAME STRUCTURETRUCK ANALOGY contd.

Virtual ContainerSection

Overhead

Payload

Payload OverHead

Multiplexer Section

OverHead

Regenerator Section

OverHead


The Payload

The contents of the container carried by the truck represent the real value.

This ‘Payload’ is analogous to customer traffic, being carried by the ‘container’ within an SDH frame.

This Payload ‘container’ supports the transportation of spesific tributary signals.


The Section Overhead

What actually gets the contentsof the truck to it’s destination is the tractor unit.

This analogous to the network maintenance and management capability carried by the SDH frame, known as it’s Section OverHead, or SOH.


The Section Overhead (SOH) provides facilities that are required to support and maintain the transportation of customer traffic Safely across the network.

THE SOH is split into Multiplexer Section Overhead (MSOH) and Regenerator Section Overhead (RSOH).


The Virtual Container

Even if the container is loaded on to a different truck, there is a portion of overhead that always remains with it.

This is known as the Path OverHead, or POH.

The Path Overhead is directly associated with the payload capacity area, and together they form what’s known as the Virtual Container.


SDH FRAME STRUCTURE

STM-N FRAME STRUCTURE

270 x N Columns

261 x N Columns

9 x N Columns

9 R

ow

s = 8 bits/byte


SDH FRAME STRUCTUREsignal frame transmission

The principle for SDH signal frame transmission is: the bytes (8-bit) within the frame structure is transmitted byte-by-byte (bit-by-bit) from left to right and from top to bottom. After one row is transmitted, the next row will follow. After one frame is completed, the next frame will start


SDH FRAME STRUCTURESDH Rate

ITU-T defines the frequency to be 8000 frames per second for all levels in STM hierarchy

STM-1 Rate :

9 rows x 270 columns x 8 bits/byte x 8000 frames per second

= 155.52 Mb/s

STM-4 Rate :

9 rows x (270 x 4) columns x 8 bits/byte x 8000 frames per second

= 622 Mb/s


OVERHEAD ANALYSIS

SDHTERMINAL

MULTIPLEXER

SDHTERMINAL

MULTIPLEXER

SDH

SDH DIGITALX-CONNECT

Multiplexer Section

Regenerator Section

Path

MSOH MSOHRSOHRSOH

RSOHPOH


OVERHEAD ANALYSISPATH OVERHEAD

Path Trace message

Parity check

VC structure

Alarm & performance info

User channel

Multiframe indication for TUs

Path protection switching


OVERHEAD ANALYSISPATH OVERHEAD contd.

• J1 : Path Trace byte

• B3: Path BIP8 Code

• C2: Signal label byte

• G1: Path status byte

• F2, F3: Path user channels bytes

• H4: TU position indicator byte

• K3: Spare byte

• N1: Network operator byte


SDH Multiplexing Structure

STM-1 AU-4

TU-3

AUG-1

TUG-3 VC-3 C-3

VC-4 C-4

TU-12 VC-12 C-12

TUG-2

×1 ×1

×3

×1

×7

×3

139264 kbit/s

34368 kbit/s

2048 kbit/s

Pointer processing

Multiplexing

Mapping

Aligning

AUG-4

AUG-16

AUG-64

STM-4

STM-16

STM-64

×1

×1

×1

×4

×4

×4

Go to glossary


SDH Tributary Multiplexing (34M)34 Mbit/s to STM-N

34M Rate Adaptation

Add POH

1

C3

1 84

9

125μs

1 1

9

VC3

POH

125μs1 85

Next page

Packing Mapping


SDH Tributary Multiplexing (34M)

1st align

Fillgap

1 86

1

9

H1H2H3

R

×3

86

TU-3

1

H1H2H3

1

9

POH

R

R

VC-4

9

1

1 261

Aligning Stuffing

TUG-3

Multiplexing

3

Same as for C4

Multiplexing route: 1X34M 1XTU-3 3XTUG-3 1XAU-4---One STM-1 can load three 34Mbit/s signals



2 Mbit/s to STM-N

2MNextpage

125μs

POH1 4

C12

1

9

VC12

1 4

1

9

TU12

1 4

1

9

TU-PTR

Rate Adaptation

Add POH

Packing

Add Pointer

Mapping Aligning



×3

1 12

TUG-2

1

9

×7 R R

TUG-3

1 86

Multiplexing

1

9

MultiplexingSame as for C3

Multiplexing route: 1X2M 3XTU12 7XTUG-2 3XTUG-3 1XSTM-1--- One STM-1 can load 3X7X3 = 63X2M SignalsMultiplexing structure: 3-7-3 structure


SDH Network protection SDH Network protection Bidirectional Traffic

Traffic flow direction along the ring

Clockwise or counter-clockwis

T1516670-94

The traffic shares the sameequipment and link

B

A

a) Uniformly routed

B

b) Diversely routed

The traffic is ondifferent equipment

and links

A

Unidirectional Traffic

Traffic flow direction along the ring

Clockwise and counter-clockwise

T1516670-94

The traffic shares the sameequipment and link

B

A

a) Uniformly routed

B

b) Diversely routed

The traffic is ondifferent equipment

and links

A


Difference between Path and Multiplex SectionDifference between Path and Multiplex Section

Physical Layere.g. Optical fiber

Multiplex section

Path


1+1 Linear MS Protection1+1 Linear MS Protection

Protection mechanism of 1+1linear MS protection system: Concurrent sending is permanent bridging Selective receiving is switching

selective receiving

concurrentsending

TU traffic TU traffic

concurrentsending

selective receivingswitch

switch


1:N Linear MS Protection1:N Linear MS Protection

Structure of 1:N Linear MS ProtectionA B

Bridging Selector

Protection section (Transmit)

Working section 1(Transmit)

Protection section (Receive)

Working section 1(Receive)

Working section 2(Transmit)

Working section 2(Receive)

Working section N(Transmit)

Working section N(Receive)

Selector Bridging


1:1 Linear MS Protection1:1 Linear MS Protection

Protection mechanism of 1:1 linear MS protection system: Traffic flow after protection switching

switch

switch

TU traffic TU traffic

Working

Protection


Two-fiber uni-directional path protection ringTwo-fiber uni-directional path protection ring

Protection switching mechanism: Switching criteria

Transmission quality of each individual channel Usually TU-AIS, TU-LOP alarms

A

B

C

D

switch

S1

P1


Traffic flow when network is broken: Working channels=1-N/2 AU4 Protection channesl=N/2-N AU4

Two-fiber bidirectional Multiplex Section Shared Protection RingTwo-fiber bidirectional Multiplex Section Shared Protection Ring


APS controller: Transition of APS controller status:

Two-fiber bidirectional Multiplex Section Shared Protection RingTwo-fiber bidirectional Multiplex Section Shared Protection Ring


Structure: Four fibers Working channels--S1,S2, carry normal traffic Protection channels--P1,P2, protect normal

traffic

Four-fiber bidirectional Multiplex Section Shared Protection RingFour-fiber bidirectional Multiplex Section Shared Protection Ring

CA AC

CA AC

S1P1

A

C

D B

P1S1

S2P2

P2S2


SubNetwork Connection ProtectionSubNetwork Connection Protection Description:

Protection one SubNetwork Connection Can be adapted to all networks


Normal condition for unidirectional SNCP: Concurrent sending (transmit end) Selective receiving (receive end)

SubNetwork Connection ProtectionSubNetwork Connection Protection


Failure in working channels for unidirectional SNCP: Concurrent sending (transmit end) Selective receiving (receive end)



Protection Restoration: Restoration time - 10 minutes (5-12 minutes)

A

B

C

D

switch

S1

P1A

B

C

D

S1

P1



INTRODUCTION PDH & SDH On Job Training July 2006 PT Indonesia Comnets Plus.

Documents

pt indonesia comnets

mbs rate

synchronous digital

signal transmission

primary rate

mbs signals

higher rate

secondary rate