Page 1160 - 5G Basics - Core Network Aspects

2 Transport aspects

15.8.2.5 Blank clause

This clause is intentionally left blank.
15.8.2.6 ODU experimental overhead (EXP)

Four bytes are allocated in the ODU overhead for experimental use. These bytes are located in row 2,
columns 4 and 14 and row 3, columns 13 and 14 of the ODU overhead.
The ODUk contains one instance of ODU EXP overhead. The ODUCn contains n instances of the ODU EXP
overhead, numbered 1 to n (EXP #1 to EXP #n).
The use of these bytes is not subject to standardization and outside the scope of this Recommendation.

An experimental overhead is provided in the ODU OH to allow a vendor and/or a network operator within
their own (sub)network to support an application, which requires an additional ODU overhead.

There is no requirement to forward the EXP overhead beyond the (sub)network; i.e., the operational span
of the EXP overhead is limited to the (sub)network with the vendor's equipment, or the network of the
operator.

15.8.2.7 ODU reserved overhead (RES)
For the case of an ODUk, eight bytes and one bit are reserved in the ODU overhead for future international
standardization. These bytes are located in row 2, columns 1 to 2 and row 4, columns 9 to 14 of the ODU
overhead. The bit is located in row 2, column 3, bit 8 of the ODU overhead. These bytes are set to all-0s.
For the case of an ODUCn, eigth bytes and one bit in the ODU OH #1 and thirteen bytes in the ODU OH #2
to #n are reserved for future international standardization. These bytes are located in row 2, columns 1 to 2
and row 4, columns 9 to 14 of the ODU OH #1 and in row 2, columns 1 to 3 and row 4, columns 5 to 14 of
the ODU OH #2 to #n. The bit is located in row 2, column 3, bit 8 of the ODU OH #1. These bytes and bit are
set to all-0s.

15.9 OPU OH description
15.9.1 OPU OH location

The OPU overhead consists of: payload structure identifier (PSI) including the payload type (PT), the
overhead associated with concatenation, the overhead associated with the mapping of client signals into
the OPU payload and the overhead associated with the hitless adjustment of ODUflex client signals. The
OPU PSI and PT overhead locations are shown in Figure 15-26.
The OPUk contains one instance of OPU overhead. The OPUCn contains n instances of OPU overhead,
numbered 1 to n (OPU OH #1 to #n).

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