Evaluation of medium access mechanisms in HFC systems with ATM cell transport.

An important element in the performance of the Medium Access and Control (MAC) layer of Hybrid Fibre Coax (HFC) systems are the medium access mechanisms employed: e.g. requests via contention mini-slots, piggybacking requests, request polling, etc. Therefore, the starting point in the design of the MAC of ATM cell based HFC systems, is an evaluation of the candidate mechanisms, which is presented in this paper. Furthermore, it is shown that different traffic types need different ideal MAC mechanisms, or different ideal combinations of them. Several proposals will be given for different traffic classes, and while in standardization and early deployment a lot of attention goes to Internet traffic today, this paper will consider in addition also the very different traffic of ATM terminals, which is rate controlled according to the ATM traffic characteristics.