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4/11/40 page 1Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks
CONSYL
Digital Carrier SystemsDigital Carrier Systems
4/11/40 page 2Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks
CONSYL
Digital 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
CONSYL
T1 carrier systemT1 carrier system
PCM PCM PCM
PCM PCM PCM
MUX
DEMUXDS-1 frameDS-1 frame
4/11/40 page 4Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks
CONSYL
DS-1 frameDS-1 frame
channel#1
channel#1 channel
#2channel
#2 . . . . . . .. . . . . . . channel#24
channel#24
frame 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
CONSYL
T - carrierT - carrierDSIDSI
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
CONSYL
E1-frameE1-frame
00 11 22 1616 3131
125 125 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
CONSYL
E - 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
CONSYL
Digital carrier comparisonDigital carrier comparison
2.0482.048 8.4488.448 34.36834.368 139.264139.264 564.992564.992
1.5441.544 6.3126.312 44.73644.736 274.176274.176
1.5441.544 6.3126.312 32.06432.064 97.72897.728 397.200397.200
6464
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
CONSYL
PDHPDH
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
CONSYL
PDH deficiencies (I)PDH deficiencies (I)
140 MLTE
140
34
34
8
8
2
140
34
34
8
8
2
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
CONSYL
PDH 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
CONSYL
PDH 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
CONSYL
SDH & 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
CONSYL
SDH 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
CONSYL
Signaling ratesSignaling rates
SONETSONET SDHSDH Bit rate (Mbps)Bit rate (Mbps)STS-1/OC-1STS-1/OC-1 51.8451.84
STS-3/OC-3STS-3/OC-3 STM-1STM-1 155.52155.52
STS-9/OC-9STS-9/OC-9 STM-3STM-3 466.56466.56
STS-12/OC-12STS-12/OC-12 STM-4STM-4 622.08622.08
STS-18/OC-18STS-18/OC-18 STM-6STM-6 933.12933.12
STS-24/OC-24STS-24/OC-24 STM-8STM-8 1244.161244.16
STS-36/OC-36STS-36/OC-36 STM-12STM-12 1866.241866.24
STS-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
CONSYL
Synchronous 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
CONSYL
SyncronizationSyncronization 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
#1
POH
#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
CONSYL
SONET 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
CONSYL
SONET Basic Frame structureSONET Basic Frame structure1 frame = 810 bytes in 1251 frame = 810 bytes in 125 ss
1 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 b
yte
s3
by
tes
6 b
yte
s6
by
tes9 b
yte
s9
by
tes
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
CONSYL
SDH 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-1
9 bytes9 bytes 261 bytes261 bytes
SOH
LOH
Payload
3 b
yte
s3
by
tes
6 b
yte
s6
by
tes9 b
yte
s9
by
tes
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
CONSYL
STM-1 FrameSTM-1 Frame9 bytes9 bytes 261 byte261 byte
ss
SOH
LOH
pointer
SOH
LOH
pointer
frame #1frame #1
frame #2frame #2
Payload #1
Payload #1
Payload #1
Payload #1
Payload #2Payload #2
POH
#1
POH
#2
4/11/40 page 23Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks
CONSYL
SOH, 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
CONSYL
SDH 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
x7x1
x3
x4
140 Mbps
45 Mbps34 Mbps
6 Mbps
2 Mbps
1.5 Mbps
STM-1
SONET-specific
Europe-specific
Universal
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
CONSYL
Containers mappingContainers mappingfi
xed
stu
ffal
ign
men
t
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
sig
nal
ing
fixe
d s
tuff
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 mapping
C-12
E1
4/11/40 page 27Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks
CONSYL
Containers, 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 b
ytes
3 bytes 4 bytes 12 bytes
4/11/40 page 28Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks
CONSYL
TU-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 columns
9 ro
ws
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
CONSYL
TUG-2 to VC-3TUG-2 to VC-3
1 84
POH
VC-3
TUG-2
4xTU-11 3xTU-12 1xTU-2
7xTUG2
9 b
ytes
9 b
ytes
9 b
ytes
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
CONSYL
AU-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
CONSYL
TUG-3 to VC-4TUG-3 to VC-4
C-3
VC-3 TU-3 TUG-3
TU-3PTR
justification bytes
9
85 86
total 260 columns
POH
3xTUG-3
VC-4
fixed stuff
4/11/40 page 32Department of Computer Engineering, Kasetsart University 204325 Introduction to Computer Communications and Networks
CONSYL
High 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
CONSYL
1xOC3 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!