Amendment 1 to Recommendation ITU-T Y.1540 introduces Appendices VII and VIII.

Appendix VII builds on the fundamental Y.1540 definitions and concepts to describe a new set of performance parameters. The objective of the new parameters is to provide information relevant to the design and configuration of higher-layer (application-layer) techniques to compensate for packet loss due to various causes (including errors and delay variation). Thus, the design and/or optimization of application-stream repair techniques should be simplified if these new metrics for packet performance assessment meet their goal.

Appendix VIII builds on the definitions in Recommendation ITU-T Y.1540 and provides a complementary framework of performance parameters. This framework defines parameters related to IP characteristics of an exchange link and its extension into network paths. One of the parameters in this framework is the IP-layer available capacity which describes the amount of network capacity that is available for network applications to utilize without causing congestion.