Alcatel-Lucent 1643 AMS Applications And Planning Manual page 279

An SDH overview
SDH digital multiplexing
...................................................................................................................................................................................................................................
Digital multiplexing is SDH's method of byte mapping tributary signals to a higher
signal rate, which permits economical extraction of a single tributary signal without the
need to demultiplex the entire STM-1 payload. In addition, SDH provides overhead
channels for use by OAM&P groups.
SDH digital multiplexing
The following figure illustrates the SDH technique of mapping tributary signals into
the STM frames.
C-4-256C
C-4-64C
C-4-16C
C-4-4C
C-4
VC-3 TU-3
C-3
C-2 VC-2 TU-2
C-12 VC-12 TU-12
C-11 VC-11 TU-11
Transporting SDH payloads
Tributary signals are mapped into a digital signal called a virtual container (VC). The
VC is a structure designed for the transport and switching of STM payloads. There are
various sizes of VCs: VC-11, VC-12, VC-2, VC-3, VC-4, VC-4-4C, VC-4-16C,
VC-4-64C and VC-4-256C.
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365-312-801R7.2
Issue 3, May 2007
VC-4-256C
VC-4-64C
VC-4-16C
VC-4-4C
VC-4
1
3
TUG-3
VC-3
1 7
TUG-2
7
3
4
Alcatel-Lucent - Proprietary
See notice on first page
AU-4-256C
AU-4-64C
1
AU-4-16C
1
AU-4-4C AUG-4
1
4
AU-4 AUG-1
3
AU-3
...
Pointer processing
Multiplexing
Aligning
Mapping
1
AUG-256
4
1
AUG-64
4
AUG-16
4
1
STM-256
1
STM-64
1
STM-16
1
STM-4
1
STM-1
1
STM-0
A-11