Summary

Corrigendum 1 to Recommendation ITU-T G.709/Y.1331 (2009) removes the definition of OTLk‑AIS (clause 16.4.2, Annex C), clarifies the minimum and maximum values of C_m and C_n (clauses 17.7.1, 17.7.2, 17.7.3, 19.6.1, 19.6.2, 19.6.3, clause D.2), clarifies that the GFP Payload FCS is not used in the mapping of 100BASE-X into OPU0 (clause 17.7.1.1), corrects the transcoding factor "T" descriptions in the notes in clauses 17.7.3, 17.7.4 and 17.7.5, renames some OPUflex overhead bytes associated with mapping of a CBR client signal (clause 17.9), corrects two typos in Table 19‑4 (clause 19.1.4), corrects the C_m(t) encoding and decoding text (clause D.3), corrects a typo in Figure D.7 (clause D.3) and corrects a typo in item 3 in clause D.4.