Page 1233 - 5G Basics - Core Network Aspects

Transport aspects 2

mechanism. Each group of M bytes in the ODTU4.M payload area may either carry M ODU bytes, or carry M
stuff bytes. The value of the stuff bytes is set to all-0s.

The groups of M bytes in the ODTU4.M payload area are numbered from 1 to 15200.
The ODTU4.M payload byte numbering for GMP M-byte (m-bit) blocks is illustrated in Figure 19-29. In row
1 of the ODTU4.M multiframe the first M-bytes will be labelled 1, the next M-bytes will be labelled 2, etc.

Figure 19-29 – ODTU4.M GMP byte numbering

20 Mapping ODUk signals into the ODTUCn signal and the ODTUCn into the OPUCn tributary slots

This clause specifies the multiplexing of:
– ODUk into OPUCn using a client agnostic generic mapping procedure (GMP).
This ODUk into OPUCn multiplexing is performed in two steps:

1) asynchronous mapping of ODUk into optical data tributary unit (ODTUCn) using GMP;
2) byte-synchronous mapping of ODTUCn into one or more OPUCn tributary slots.
The OPUCn supports up to 10n different ODUk signals.

20.1 OPUCn tributary slot definition

The OPUCn consists of n OPUC. Each OPUC is divided into 20 tributary slots (TS) and these tributary slots
are 16-byte interleaved within the OPUC payload area. A tributary slot includes a part of the OPUC OH area
and a part of the OPUC payload area. The bytes of the ODUk frame are mapped into the ODTUCn payload
area and the ODTUCn bytes are mapped into the OPUCn tributary slot or slots. The bytes of the ODTUCn
justification overhead are mapped into the OPUCn OH area.

There is only one type of tributary slot:
1) Tributary slot with a bandwidth of approximately 5 Gbit/s; an OPUCn is divided into 20n tributary
slots, numbered 1.1 to n.20.

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