SummaryAmendment 4 to Recommendation ITU-T G.709/Y.1331 (2012) contains extensions related to the: − addition of the OTSn OTN synchronization messaging channel (OSMC) overhead; − addition of the OTUk OTN synchronization messaging channel (OSMC) overhead; − modification of the OCh overhead transport over OTM-1 multi-vendor IaDI specification to align with the specifications in Recommendation ITU-T G.7712; − addition of optional FEC processing in the FC-1600 client signal. |