AN ATM-FRIENDLY MAC FOR TRAFFIC CONCENTRATION IN HFC SYSTEMS

Proliferating deployment of amphidromic broadband services over commer cial cable TV networks is bringing a taste of IBCN capabilities to vas t numbers of domestic customers. The fluctuating and unpredictable tra ffic of the new services favours TDMA multiplexing of traffic fi om ma nu customers inside each channel for flexible and dynamic bandwidth sh aring on the basis of a medium access protocol, As penetration grows, traffic aggregations will exceed the capabilities of store-and-forward switching bringing more and more into prominence fast switching techn iques and ATM networking. The first HFC systems designed primarily for LAN interconnection and Internet traffic are not optimised for ATM so urces even when they employ ATM cells as a unit of transport. A novel contention approach designed to greatly reduce the distortions to traf fic profiles characterising first generation HFC medium access protoco ls is the theme of this paper, The proposed method provides a high num ber of simultaneous orthogonal contention opportunities which allow qu ick identification of cell arrivals which is a key to preserving tempo ral relationships of contending traffic, vastly reducing cell delay va riations in line with the traffic control philosophy of ATM. (C) 1998 Elsevier Science B.V.