SDH transport rates
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Higher rate STM-N frames are built through byte-multiplexing of N STM-1 signals.
Creating higher rate signals
A STM-N signal can only be multiplexed out of N STM-1 frames with their first A1
byte at the same position (i.e. the first A1 byte arriving at the same time).
STM-N frames are built through byte-multiplexing of N STM-1 signals. Not all bytes
of the multiplexed SOH (size = N x SOH of STM-1) are relevant in an STM-4/16.
For example there is only one B1 byte in an STM-4/16 frame which is computed the
same way as for an STM-1. Generally the SOH of the first STM-1 inside the STM-N
is used for SOH bytes that are needed only once. The valid bytes are given in ITU-T
G.707.
Designation
Line rate (Mbit/s)
Capacity
STM-1
155.520
1 AU-4 or 3 AU-3
STM-4
622.080
4 AU-4 or 12 AU-3
STM-16
2488.320
16 AU-4 or 48 AU-3
STM-64
9953.280
64 AU-4 or 192 AU-3
STM-256
39813.120
256 AU-4 or 768 AU-3
An SDH overview
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A-16
Lucent Technologies - Proprietary
See notice on first page
365-312-847R4.0
Issue 4, November 2006