Summary

This annex includes descriptions of 256-QAM for downstream and 16-QAM for upstream in Physical Layer. These modulation functions enable cable television networks to transmit high speed programme data and IP Packets as well. However, the most significant change of this revised annex is an enhancement of MAC Layer the descriptions for QoS oriented services such as Voice over IP, Video over IP. The enhancement includes Extension of MAC Frame Format, Extension for QoS Control Function, Payload Header Suppression and Multicast Extension.