Page 1174 - 5G Basics - Core Network Aspects

2 Transport aspects

Figure 17-8  OPU frame structure and mapping of a NULL client into OPU

The OPU overhead for the NULL mapping consists of a payload structure identifier (PSI) including the
payload type (PT) and 255 bytes reserved for future international standardization (RES), and seven bytes
reserved for future international standardization (RES).

The OPU payload for the NULL mapping consists of 4 × 3808 bytes.
The OPUk contains one instance of the NULL client. The OPUCn contains n instances of the NULL client,
numbered 1 to n.

17.5.2 Mapping of PRBS test signal into OPU
For end-to-end and segment turn-up test purposes, a 2 147 483 647-bit pseudo-random test sequence
31
(2  1) as specified in clause 5.8 of [ITU-T O.150] can be mapped into the OPU payload. Groups of eight
successive bits of the 2 147 483 647-bit pseudo-random test sequence signal are mapped into 8 data bits
(8D) (i.e., one byte) of the OPU payload (see Figure 17-9).

Figure 17-9  OPU frame structure and mapping of 2 147 483 647-bit
pseudo-random test sequence into OPU

The OPU overhead for the PRBS mapping consists of a payload structure identifier (PSI) including the
payload type (PT) and 255 bytes reserved for future international standardization (RES), and seven bytes
reserved for future international standardization (RES).
The OPU payload for the PRBS mapping consists of 4  3808 bytes.

1164