Page 1284 - 5G Basics - Core Network Aspects

2 Transport aspects

Annex H

OTUCn sub rates (OTUCn-M)
(This annex forms an integral part of this Recommendation.)

H.1 Introduction
This annex defines a subrate OTUCn, note that subrates are not defined for the OPUCn and ODUCn.
Additional descriptive text, examples and applications are provided in Appendix XIII.
The OPUCn, ODUCn and OTUCn are defined in terms of n x 100 Gbit/s signals. For the MOTUm interface it
may be advantageous to carry an OTUCn with a bit rate that is not constrained to be an integer multiple of
100 Gbit/s. This OTU is described as an OTUCn-M.

H.2 OTUCn-M frame format
The OTUCn-M frame is a type of OTUCn frame which contains n instances of OTUC, ODUC and OPUC
overhead and M 5 Gbit/s OPUCn tributary slots. If a particular value of M is not indicated, the frame
contains 20*n tributary slots. See Appendix XIII for examples.

An OTUCn-M framed signal can be carried over MOTUm interfaces. Values of M supported and the subset
of the 20n 5 Gbit/s OPUCn tributary slots that are included in the OTUCn-M on such a MOTUm interface are
vendor specific and outside the scope of this recommendation.

The OPU tributary slots that are included in the OTUCn-M structure will have their availability bit in the
OPUCn MSI overhead set to "available" (see 20.4.1.1). The OPU tributary slots which might not be carried
transparently by the OTUCn-M structure will have their availability bit in the OPUCn MSI overhead set to
"unavailable" (see 20.4.1.1). The data in tributary slots marked as unavailable must be set to "all 0".

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