Evaluation of IP oriented HFC access protocols

The proliferation of HFC access systems enriching with digital bi-directional services the old analog cable TV plants, coupled with the emergence of the Internet as the dominant interactive application, make expedient the optimization of the access protocols for TCP/IP. The shared medium in the upstream and the buffer management policies in the cable modem need to implement mechanisms adapted to the bursty nature of traffic and the loss-oriented congestion avoidance mechanisms of TCP. Several packet discard policies are evaluated in conjunction with the MAC protocol, showing that significant throughput improvements can be achieved over the plain tail drop policy in the modem queue.