This amendment contains extensions to the third version (12/2009) of ITU-T Recommendation G.709/Y.1331, related to the addition of: - Addition of IB SDR, IB DDR and IB QDR client mappings (clauses 2, 4, 15.9.2.1.1, 17.9, Appendix IX, Bibliography) - Enhancement of the recommended ODUflex(GFP) bit rate values (clauses 3.2, 4, 7.3, 12.2.5, Appendix XI) - Modification of the BIP-8 processing in 40GBASE-R and 100GBASE-R (clauses 17.7.4.1, 17.7.5.1, B.3.1, E.3, E.3.2, E.4.1, E.4.2) - Clarification of the ODU maintenance signal (AIS, LCK, OCI) bit rate range (clause 7.3) - Clarification of the number of tributary slots occupied by ODUflex signals transported in OPU2, OPU3 and OPU4 (clauses 7.3, 19.6.1, 19.6.2, 19.6.3, Appendix VIII, Appendix X) - Extension of Table IX-1 with 40GBASE-R, 100GBASE-R, IB SDR, IB DDR and IB QDR client into LO OPU mapping types and replacement of "n" in CnD by their standardized values (Appendix IX).