Protection - Siemens SRA 4 User Manual

Fig. 1.1
STM1
(155)
150.912
ALL VALUES IN MBIT/S
Fig. 1.2
SRA 4 - 6/7/8/10/11/13 GHz (WB ODU) - UMN
911-381/02C0000 - Issue 3, July 2004
SDH multiplex structure (ETSI)
AU4 VC4
49.536
150.336
3X
TUG3
7X
CHANGE LEVEL
STM-1 frame structure
3
1
9 RIGHE
5
Essentially, each frame is composed of:
– one frame head, called SOH (section overhead), shown in Fig. 1.3, which occupies
the first 9 bytes of each line except the fourth, and is used for transmission of
service information;
– the rest of 261x9 bytes plus the first 9 bytes of the fourth line which represent the
administrative unit AU-4. The administrative units (AU) are digital structures of
higher order contained in the STM-1 frame and are particularly suitable for the
operational of the SDH network, such as for example the rerouting of digital
streams for protection of the network.
48.960
49.152
TU3 VC3
6.912
6.912 6.848
TU2 VC2
TUG2
2304
2.240
3X
TU12 VC12
1.664
270 BYTES
9
RSOH
MSOH
Frame length = 125 sec
o
RSOH = Regenerator Section Overhead
MSOH = Multiplexer Section Overhead
1 - PRELIMINARY INFORMATION
C4
149.760
48.384
C3
6.784
C2
2.176
C12
VC11 C11
1.600
261
ADMINISTRATIVE UNIT
"AU-4"
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