Amendment 1 to Recommendation G.8013/Y.1731 provides: - New OAM PDU called "Generic Notification Message" - New OAM functions and mechanism for Bandwidth Notification (ETH-BN) that notifies the change of bandwidth of link to MEPs. Its PDU uses Generic Notification Message with a SubOpCode for Bandwidth Notification. - New OAM functions and mechanism for Expected Defect (ETH-ED) that enables transmission of CCM frames expected to be interrupted without any interruption to data frames. Its PDU uses MCC with SubOpCode for Expected Defect. - transmission of CCM frames expected to be interrupted without any interruption to data frames. Its PDU uses MCC with ITU-T OUI (00-19-A7) and SubOpCode for Expected Defect. - Some corrections in clause 2 - New abbreviations to ETH-BN and ETH-ED in clause 4