Amendment 1 to Recommendation ITU-T G.8260 (2012): Adds a reference in clause 2; Modifies definition 3.1.8, "packet-based method with timing support from the network"; Adds a number of definitions in clause 3.1; Adds new clause I.5.1 to Appendix I, describing the determination of floor delay and discussion of the impact of re-route events; Adds new clause I.5.2 to Appendix I, describing the impact of exceptional events on packet network limit.