RESERVATION ARBITRATED ACCESS - A BANDWIDTH ON DEMAND PROTOCOL FOR MULTIPLEXING VARIABLE BIT-RATE ISOCHRONOUS TRAFFIC OVER DUAL BUS METROPOLITAN-AREA NETWORKS

With the advent of multimedia communication services, transport of rea l-time traffic over metropolitan area networks (MANs) is becoming an i mportant problem. We present a novel reservation arbitrated (RA) acces s protocol for multiplexing variable bit rate isochronous (VERI) traff ic such as packet voice and video over dual bus MANs in general and IE EE 802.6 MANs in particular. In combination with a cyclic release mech anism, RA access allows variable bit rate traffic sources (VBRSs) to c apture and reserve some isochronous channels on a bandwidth on demand basis in a round robin fashion. For a reasonable bus length suitable f or metropolitan coverage, it is possible to select operation parameter s which enable contention free access in the reservation process. Band width utilization can be further improved by employing a movable bound ary option to efficiently integrate VERI traffic with other traffic. S ystem performances including packet loss ratio, packet delay, delay ji tter, probability distribution of consecutive packet loss and channel utilization are analyzed by both theoretical computations and computer simulations for voice, video conference and motion video traffic. Res ults indicate that the protocol is fair and provides a nearly isochron ous transport service while ensuring efficient bandwidth utilization, yielding substantial capacity improvements over pre-arbitrated (PA) ac cess. Compared to queue-arbitrated (QA) access, RA access not only pro vides variable bit rate isochronous channels but also allows VBRSs to adapt to the reserved bandwidth during network congestion so that perf ormance degradation can be minimized, RA access complements existing P A and QA access methods in 802.6 MANs to provide a complete traffic tr ansport solution for all types of BISDN services. (C) 1997 Elsevier Sc ience B.V.