Recent progress of the Optical Transport Network (OTN) has introduced
new signal types (i.e., ODU0, ODU4, ODU2e and ODUflex) and new
Tributary Slot granularity (1.25Gbps).
Since equipments deployed prior to recently defined ITU-T
recommendations only support 2.5 Gbps Tributary Slot granularity and
ODU1, ODU2 and ODU3 containers, the compatibility problem should be
considered. In addition, a Higher Order ODU (HO ODU) link may not
support all the types of Lower Order ODU (LO ODU) signals defined by
the new OTN standard because of the limitation of the devices at the
two ends of a link. In these cases, the control plane is required to
run the capability discovering functions for the evolutive OTN.
This document describes the extensions to the Link Management
Protocol (LMP) needed to discover the capability of HO ODU link,
including the granularity of Tributary Slot to be used and the LO ODU
signal types that the link can support.