SDH Theory*
ISO 9001:2008
What is SDH?SDH = Synchronous Digital HierarchyIt is a transport
networksynchronousfully standardizedwith high bandwidthfor
synchronous and asynchronous signals
*
ISO 9001:2008
for future broadband signals and new serviceswith standardized
network management capabilitieswith traffic protectionwith a
flexible multiplexing structuredirect access to
tributariescross-connections without de-multiplexing*
ISO 9001:2008
Digital Transmission SystemRegeneratorrecreates the
signal.Multiplexer (MUX)Multiplexer combines data from several
lines and transmits it over a higher-capacity data link.*
No signalRRegeneratorMUXMUX
ISO 9001:2008
Multiplexer Naming ConventionsTerminal Multiplexer (TM)All
traffic is terminated here.m: aggregate leveln: lowest tributary
levelAdd-Drop Multiplexer (ADM)Part of the traffic is
terminated.Part of the traffic goes transparently through.*
aggregatetributaries
ISO 9001:2008
Digital Cross-connect (DXC m/n)No traffic is
terminated.Cross-connection matrix connects tributary signals of
one aggregate to another aggregate.*
PDHMUXPDHMUXPDHMUXPDHMUXDDFSDHCross-Connect
ISO 9001:2008
PDH Bit Rates & HIERARCHY*
Hierarchy level
USA
Europe
0
64 kbit/s
T0
64 kbit/s
E0
1
1.544 Mbit/s
T1 (24x)
2.048 Mbit/s
E1 (32x)
2
6.312 Mbit/s
DS-2 (4x)
8.448 Mbit/s
E2 (4x)
3
44.736 Mbit/s
DS-3 (7x)
34.368 Mbit/s
E3 (4x)
4
139.264 Mbit/s
E4 (4x)
ISO 9001:2008
SDH Bit Rates & HIERARCHY*
SONET (ANSI)
SDH(ITU-T)
Data rate (Mbps)
STS-1
51.84
STS-3
STM-1
155.52
STS-9
466.56
STS-12
STM-4
622.08
STS-18
933.12
STS-24
1244.16
STS-36
1866.24
STS-48
STM-16
2488.32
STM-64
9953.28
ISO 9001:2008
PDH vs. SDH Add & Drop Function*
Six TMs needed to drop E1One ADM is enough to drop E1.PDHSDH
ISO 9001:2008
STM-1 Frame*
2430 bytes/frame 8 bit/byte 8000 frame/s = 155.52
Mbit/stransmitted from top to bottom and left to right
ISO 9001:2008
SDH Multiplexing Structure (ETSI)*
Pointer processingMultiplexingAligningMappingC ContainerVC
Virtual ContainerTU Tributary UnitTUG Tributary Unit GroupAU
Administrator UnitAUG Administrator Unit Group
ISO 9001:2008
PDH over SDHContainer (C)basic payload unitVirtual Container
(VC)C + POH (path overhead)Tributary Unit (TU)VC + pointerThe
pointer indicates the start of the VC and allows dynamic alignment
of the VC within the TU frame.*
2 Mbit/s plesiochronous streamJustification bytesC12Path
OverheadVC12ContainerPOHTU PointerTU12Virtual Container
ISO 9001:2008
KLM CoordinatesVC-4
POHVC-12VC-12KLTU12-1TU12-2TU12-3TUG3-1TUG3-2TUG3-3TUG2-6TUG2-7TUG2-5TUG2-4TUG2-3TUG2-1TUG2-2TUG-3
number (values 1-3)TUG-2 number (values 1-7)TU-12 number (values
1-3)KLM: 271KLM: 152KLM: 300VC-3
ISO 9001:2008
Termination of Sections*
TMTM
ISO 9001:2008
RegeneratorRegenerates the optical signal.
Terminates RSOH.*
REGSTM-NSTM-N
ISO 9001:2008
Terminal MultiplexerTerminates RSOH and MSOH.May terminate HOP
and LOP overhead.Multiplexes/maps tributary signals.Includes timing
and management functions.*
TMSTM-N orPDHSTM-M
ISO 9001:2008
Add/drop MultiplexerTerminates RSOH and MSOH.May terminate HOP
and LOP overhead.Includes connection function between the two
aggregates.Multiplexes/maps tributary signals.Includes a connection
function for allocation of TUs within the STM frame. Includes
timing and management functions.*
STM-N or PDHSTM-MSTM-MADM
ISO 9001:2008
Cross-connect*
Terminates RSOH and MSOH.Includes connection function between
the aggregates.Can have tributary ports, for which it may terminate
HOP and LOP overhead.Includes timing and management functions.STM-N
or PDHSTM-MSTM-MDXC
ISO 9001:2008
SDH OverheadOverheads carry information for monitoring,
maintaining and controlling the operation of network.Overhead
typesPOH for end-to-end monitoring of payload signal (VC-12, VC-3
and VC-4)Block errors, far end alarms, trace and payload typeSOH is
used for monitoring of signal between SDH equipment. RSOH: block
errors, traceMSOH: block errors, synchronization, and far-end
alarms*
ISO 9001:2008
RSOHA1, A2framing patterns (F6H), (28H)J0regenerator section
Trail Trace Identifier (TTI)B1BIP-8 parity byteE1RS orderwire
channel (service telephone)F1user (network operator) data
channelD1, D2, D3regenerator section Data Communication Channel
(DCCR)NU1, NU2, NU3, NU4bytes reserved for national useR1, R2, R3,
R4, R5, R6media specific bytes (e.g. radio link)U1, U2, U3, U4bytes
with no defined use*
1
2
3
4
5
6
7
8
9
RSOH
1
A1
A1
A1
A2
A2
A2
J0
NU1
NU2
RSOH
2
B1
R1
R2
E1
R3
U1
F1
NU3
NU4
RSOH
3
D1
R4
R5
D2
R6
U2
D3
U3
U4
PTR
4
H1
Y1
Y2
H2
1
1
H3
H3
H3
MSOH
5
B2
B2
B2
K1
U5
U6
K2
U7
U8
MSOH
6
D4
U9
U10
D5
U11
U12
D6
U13
U14
MSOH
7
D7
U15
U16
D8
U17
U18
D9
U19
U20
MSOH
8
D10
U21
U22
D11
U23
U24
D12
U25
U26
MSOH
9
S1
Z12
Z13
Z21
Z22
M1
E2
NU5
NU6
ISO 9001:2008
MSOHB2BIP-24 parity bytesK1, K2Automatic Protection Switching
(APS) channel, D4 to D12multiplex section Data Communication
Channel (DCCM)S1synchronization statusM1Remote Error Indication
(REI)E2MS orderwire channel (service telephone)NU5, NU6bytes
reserved for national useU5 to U26bytes with no defined useZ12,
Z13, Z21, Z22bytes with no defined use*
1
2
3
4
5
6
7
8
9
RSOH
1
A1
A1
A1
A2
A2
A2
J0
NU1
NU2
RSOH
2
B1
R1
R2
E1
R3
U1
F1
NU3
NU4
RSOH
3
D1
R4
R5
D2
R6
U2
D3
U3
U4
PTR
4
H1
Y1
Y2
H2
1
1
H3
H3
H3
MSOH
5
B2
B2
B2
K1
U5
U6
K2
U7
U8
MSOH
6
D4
U9
U10
D5
U11
U12
D6
U13
U14
MSOH
7
D7
U15
U16
D8
U17
U18
D9
U19
U20
MSOH
8
D10
U21
U22
D11
U23
U24
D12
U25
U26
MSOH
9
S1
Z12
Z13
Z21
Z22
M1
E2
NU5
NU6
ISO 9001:2008
Functions of POH (Path Overhead)* Parity check (B3, V5/BIP-2
calculated by terminating point) * Alarm and performance
information (V5, G1)* Structure of VC (Signal label C2)*
Multi-frame indication for TUs (H4) * User communication
channel-between path elements (F2, F3)Identification of path source
(path trace J1, J2) Functions and characteristics of the individual
elements
1) The Administrative Unit (AU) * Is shaped if a pointer is
allocated to the VC formed at last* Clock justification through
positive zero-negative stuffing in the AU pointer area * Byte by
byte stuffing
*
ISO 9001:2008
2) The container (C) * Basic packaging unit for tributary
signals (PDH) * Synchronous to STM-1 * Bit rate adaptation is done
via a positive stuffing procedure * Adaptation of synchronous
tributaries by fixed stuffing bits * Bit by bit stuffing
*
ISO 9001:2008
3) The virtual container (VC) * Formation of the container by
adding of POH (Path Overhead) * Transport as a unit through the
network (SDH) * A VC containing several VCs has also same pointer
area4) The Tributary Unit (TU) * Is formed by adding pointer to
*
5) Tributary Unit Group (TUG) * Combines several TUs for new
VC
ISO 9001:2008
*
ISO 9001:2008
Any Questions?
ISO 9001:2008
THANK YOU
FIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*E1
frame (PDH):
2048 kbps = 32 TS/frame 8 bit/TS 8000 frame FAS (1 TS) + 31
channels (31 TS) FAS (1 TS) + CAS (1 TS) + 30 channels (30 TS) 8:
number of bits per byte 8000: 1 frame lasts 125 s
FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOMFIBCOM*FIBCOM
