4/11/40 page 1Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLDigital Carrier SystemsDigital Carrier Systems

4/11/40 page 2Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLDigital carrier standardDigital carrier standard

T-carrierT-carrier North America, Japan

E-carrierE-carrier Europe, Mexico, South America

4/11/40 page 3Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLT1 carrier systemT1 carrier system

PCM PCM PCM

PCM PCM PCM

MUX

DEMUXDS-1 frame

4/11/40 page 4Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLDS-1 frameDS-1 frame

channel#1

channel#2 . . . . . . . channel

#24frame frame bitbit

193 bits193 bits

data rate = (24x8 +1 bit)/125 data rate = (24x8 +1 bit)/125 s = 1.544 Mbpss = 1.544 Mbps

8 bit8 bit

• each channel also refers as DS0each channel also refers as DS0

125 125 ss

4/11/40 page 5Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLT - carrierT - carrier

DSIDSI

DSICDSIC

DS2DS2

DS3DS3

DS4DS4

DSICDSIC

DS2DS2DS2DS2 DS2DS2 DS2DS2 DS2DS2DS2DS2

DS3DS3DS3DS3 DS3DS3DS3DS3DS3DS3

DSIDSI

Two 1.544 Mbps DS1 channels arTwo 1.544 Mbps DS1 channels are multiplexed into a single 3.152 Me multiplexed into a single 3.152 Mbps DS1C channelbps DS1C channel

Two DS1C channels are multiplTwo DS1C channels are multiplexed into a single 6.312 Mbps exed into a single 6.312 Mbps DS2 channelDS2 channel

Seven DS2 Seven DS2 channels achannels are multiplere multiplexed into a xed into a single 44.7single 44.736 Mbps D36 Mbps DS3 channelS3 channel

Six DS3 channels are multipleSix DS3 channels are multiplexed into a single 274.176 Mbpxed into a single 274.176 Mbps DS4 channels DS4 channel

4/11/40 page 6Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLE1-frameE1-frame

0 1 2 16 31125 125 s = 32 time slots = 2.048 Mbpss = 32 time slots = 2.048 Mbps

frame synchronization signaling channel

30 voice channel+2 control channel

4/11/40 page 7Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLE - carrierE - carrier

E1E1 E1E1 E1E1 E1E1

E2E2E2E2 E2E2 E2E2

E3E3E3E3 E3E3 E3E3

E4E4E4E4 E4E4 E4E4

E5E5

Thirty 64 kbps channels arThirty 64 kbps channels are multiplexed to create one e multiplexed to create one 2.048 Mbps E1 channel2.048 Mbps E1 channel

Four E1 channels are multiplexeFour E1 channels are multiplexed into a single 8.448 Mbps E2 chd into a single 8.448 Mbps E2 channelannel

Four E2 channels are mulFour E2 channels are multiplexed into a single 34.3tiplexed into a single 34.368 Mbps E3 channel68 Mbps E3 channel

Four E3 channels Four E3 channels are multiplexed inare multiplexed into a single 139.26to a single 139.264 Mbps E4 chann4 Mbps E4 channelel

Four E4 channels are mulFour E4 channels are multiplexed into a single 565.tiplexed into a single 565.148 Mbps E5 channel148 Mbps E5 channel

4/11/40 page 8Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLDigital carrier comparisonDigital carrier comparison

2.048 8.448 34.368 139.264 564.992

1.544 6.312 44.736 274.176

1.544 6.312 32.064 97.728 397.200

64

J1

E1

T1

J2

E2

T2

J3

E3

T3

J4

E4

T4

J5

E5x31

x24

x24

x 4

x 4

x 4

x 4

x 7

x 5

x 4

x 6

x 3

x 4

x 4

EuropEuropee

USAUSA

JapanJapan

4/11/40 page 9Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLPDHPDH

Digital tramsmission systems (T-carrier, E carrier) combine lower order multiplex stream to get higher bit rate

Different streams have small differences in clock signals.

Solve by adding justification bit PDH = Plesiochronous Digital Hierachy

almost synchronous

4/11/40 page 11Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLPDH deficiencies (I)PDH deficiencies (I)

140 MLTE

140

34

348

82

140

34

348

82

140 MLTE

34 Mbps34 Mbps

8 Mbps8 Mbps

2 Mbps2 Mbps

Customer siteCustomer site

Lack of flexibility impossible to identify a lower bit rate channel from the higher-order

bit stream.

demux the high bit rate down to the lower level remux back into higher

level for onward transmission

Extraction of 2 Mbps channel from 140 Mbps channel

4/11/40 page 12Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLPDH deficiencies (II)PDH deficiencies (II)

Lack of performance No standard for monitoring the performance of traffic channel No management channel

4/11/40 page 13Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLPDH deficiencies (III)PDH deficiencies (III)

Lack of 慚 id-Fibre meet undefined interface specification on the line side of a line transmissi

on

LTE

G.703interface

non standardline code andoptical levels

standard NetworkNode Interface (NNI)

functional integrationof MUX and LTE

PDH SDH

4/11/40 page 14Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSDH & SONETSDH & SONET

What is SDH/SONET ?What is SDH/SONET ? Standard interface developed for using in the public network multiplexing standard for optical fiber transmission

SONET = Synchronous Optical Network refers to the system used within the U.S. and Canada

SDH = Synchronous Digital Hierarchy international community term (ITU-T recommendtions)

4/11/40 page 15Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSDH goalsSDH goals

GoalsGoals make it possible for different carrier to interwork unify the U.S., European and Japanese digital system Provide a way to multiplex multiple digital signal togethers provide support for operations, administration, and maintenace

Characteristics use single master clock to synchronize Bit stream can be a added or extracted directly Basic transmission rate = 155.52 Mbps

4/11/40 page 16Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSignaling ratesSignaling rates

SONETSONET SDHSDH Bit rate (Mbps)Bit rate (Mbps)STS-1/OC-1STS-1/OC-1 51.8451.84STS-3/OC-3STS-3/OC-3 STM-1STM-1 155.52155.52STS-9/OC-9STS-9/OC-9 STM-3STM-3 466.56466.56

STS-12/OC-12STS-12/OC-12 STM-4STM-4 622.08622.08STS-18/OC-18STS-18/OC-18 STM-6STM-6 933.12933.12STS-24/OC-24STS-24/OC-24 STM-8STM-8 1244.161244.16STS-36/OC-36STS-36/OC-36 STM-12STM-12 1866.241866.24STS-48/OC-48STS-48/OC-48 STM-16STM-16 2488.322488.32

STS = Synchronous Transport SignalSTS = Synchronous Transport SignalOC = Optical CarrierOC = Optical CarrierSTM = Synchronous Transport ModuleSTM = Synchronous Transport Module

4/11/40 page 17Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSynchronous ContainerSynchronous Container

1.5 Mbps2 Mbps

6 Mbps

Each PDH stream is carried in an appropiate container

container 1.5 Mbps 2 Mbps 6 Mbps

PDH signal

1.5 Mbps 2 Mbps 6 Mbpsvirtualcontainer

Path overhead for monitoring 抯 purpose

4/11/40 page 18Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSyncronizationSyncronization 抯 抯 techniquestechniques

• phase offset in byte

• directly access signal signal using pointer

• data begins anywhere in frame

pointer

pointer

data #1

data #1

data #1

data #1

data #2data #2

POH

#1PO

H #2

sample frame

frame #1frame #1

frame #2frame #2

4/11/40 page 19Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSONET SystemSONET System

consists of switches, mux and repeatersconsists of switches, mux and repeaters

sectionsection section section

line line

path

muxmux repeatersrepeaters repeatersrepeatersmuxmux muxmux

4/11/40 page 20Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSONET Basic Frame structureSONET Basic Frame structure

1 frame = 810 bytes in 1251 frame = 810 bytes in 125 ss1 2 3 4 5 6 7 8 91 2 3 4 5 6 7 8 9

STS-1/OC1STS-1/OC1

3 bytes3 bytes 87 bytes87 bytes

SOH

LOH

Payload

3 by

tes

3 by

tes

6 by

tes

6 by

tes9

byte

s9

byte

s

TOHTOH

OverheadOverhead : : for system management for system management informationinformation

SOH = Section OverheadSOH = Section OverheadLOH = Line OverheadLOH = Line OverheadTOH = Transport OverheadTOH = Transport Overhead

Payload Payload : user data: user data

row/column mapping row/column mapping

4/11/40 page 21Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSDH Basic Frame structureSDH Basic Frame structure

1 frame = 2430 bytes in 1251 frame = 2430 bytes in 125 ss1 2 3 4 5 6 7 8 91 2 3 4 5 6 7 8 9

STM-1STM-19 bytes9 bytes 261 bytes261 bytes

SOH

LOH

Payload

3 by

tes

3 by

tes

6 by

tes

6 by

tes9

byte

s9

byte

s

TOHTOH

OverheadOverhead : : for system management for system management information (OAM)information (OAM)

SOH = Section OverheadSOH = Section OverheadLOH = Line OverheadLOH = Line OverheadTOH = Transport OverheadTOH = Transport Overhead

Payload Payload : user data: user data

row/column mapping row/column mapping

4/11/40 page 22Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSTM-1 FrameSTM-1 Frame

9 bytes9 bytes 261 byte261 bytess

SOH

LOH

pointer

SOH

LOH

pointer

frame #1frame #1

frame #2frame #2

Payload #1

Payload #1

Payload #1

Payload #1

Payload #2Payload #2

POH

#1PO

H #2

4/11/40 page 23Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSOH, LOH and POH SOH, LOH and POH

A1 A2 C1 J1B1 E1 F1 B3 D1 D2 D3 C2H1 H2 H3 G1B2 K1 K2 F2 D4 D5 D6 H4D7 D8 D9 Z3D10 D11 D12 Z4 Z1 Z2 E2 Z5

section overhead

line overhead

path overhead

transportoverhead

STS-1information payload

3 columns 87 columns

9 rows

4/11/40 page 24Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLSDH mux schemeSDH mux scheme

AUG AU-4 VC-4

TUG-3 TU-3 VC-3

C-4

VC-3AU-3

TUG-2 TU-2 VC-2 C-2

TU-12 VC-12 C-12

TU-11 VC-11 C-11

C-3

x1

x3

x3

x7

x7 x1

x3

x4

140 Mbps

45 Mbps34 Mbps

6 Mbps

2 Mbps

1.5 Mbps

STM-1

SONET-specificEurope-specificUniversal

PDHTributaries

4/11/40 page 25Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYL

Administrative Unit

Tributary Unit Group

SDH ElementsSDH Elements

Containers

Virtual Containers

Tributary UnitAdministrative Unit

Administrative Unit Group

path overhead

pointer

Tributary Unit Group

Tributary UnitTributary Unit

section overhead

STM-1

4/11/40 page 26Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLContainers mappingContainers mapping

fixed

stu

ffal

ignm

ent

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

sign

alin

g

fixed

stu

ff

containers #bytes capacityC-11 25 1.600C-12 34 2.176C-2 106 6.784C-3 672 48.384C-4 2340 149.760

sample C2 mappingC-12E1

4/11/40 page 27Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLContainers, VC & TUContainers, VC & TUC-11 C-12 C-2

VC-11 VC-12 VC-2

TU-11 TU-12 TU-2

plus POH

plus pointer

9 by

tes

3 bytes 4 bytes 12 bytes

4/11/40 page 28Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLTU-X formatTU-X format

1 2 27

1 2 3

27

1 2 3 4

36

1 2 3

108

1 2 36

1 2 108

27 bytes

36 bytes

108 bytes

TU-11

TU-12

TU-2

3 columns

9 ro

ws

4 columns

9 ro

ws

12 columns9

row

s

125 s

125 s

125 s

1728 kbps

2304 kbps

6912 kbps

4/11/40 page 29Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLTUG-2 to VC-3TUG-2 to VC-3

1 84POH

VC-3

TUG-2

4xTU-11 3xTU-12 1xTU-2

7xTUG2

9 by

tes

9 by

tes

9 by

tes

12 bytes 12 bytes 12 bytes 12 bytes

total 85 columns

TUG-2 may be • 4xTU-11• 3xTU-12• 1xTU-2

4/11/40 page 30Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLAU-3 to AUGAU-3 to AUG

J1B3C2G1F2H4Z3Z4Z5

J1B3C2G1F2H4Z3Z4Z5

J1B3C2G1F2H4Z3Z4Z5

1 30 59 87 1 30 59 87 1 30 59 87

J1B3C2G1F2H4Z3Z4Z5

J1B3C2G1F2H4Z3Z4Z5

J1B3C2G1F2H4Z3Z4Z5

1 30 59 87 1 30 59 87

H1 H2 H3 H1 H2 H3 H1 H2 H3

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

A B C

VC-3 plus 2 column fixed stuff

AU-3

3xAU-3 to AUG

1 30 59 87

4/11/40 page 31Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLTUG-3 to VC-4TUG-3 to VC-4

C-3

VC-3 TU-3 TUG-3TU-3PTR

justification bytes

9

85 86

total 260 columns

POH

3xTUG-3

VC-4fixed stuff

4/11/40 page 32Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYLHigh order muxHigh order mux

Nx9 Nx261

MUX

STM-1 #1 STM-1 #2 STM-1 #N

byte interleave

stream

4/11/40 page 33Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks

CONSYL1xOC3 and 3xoC11xOC3 and 3xoC1

OC3 = 3xOC1OC3 = 3xOC1 a 155.52 Mbps carriers consisting of 3 separated OC3 carriers

OC3c = 1X155.52Mbps carriersOC3c = 1X155.52Mbps carriers a data stream from single source of 155.52 Mbps

Higher-order frames also exist (e.g. OC12c). The amount of actual user data in an OC3c stream i

s slighly higher thanin an OC-3 stream!