Resource allocation in broadband networks-cell, burst or connection level?

Traditional data-communication services can be expected to consume only a small fraction of the available bandwidth when B-ISDN services become a reality. A variety of new communications services, ranging from continuous bit-rate digital video to highly bursty image traffic with very small activity ratios (typically close to 3%, with characteristics markedly different from data services are propelling the need for developing more efficient resource allocation and routing protocols. The level of granularity of bandwidth allocation for these bursty sources is the subject of investigation in this paper. The different choices for allocation granularity, viz., cell, burst and connection levels are discussed and compared. ON-OFF models are used to represent bursty sources. We employ MMPP models to approximate the superposition of several ON-OFF sources and investigate the delay performance of the different allocation policies at an ATM multiplexer. Results reveal that the multichannel allocation at the cell level) allocation offers an order of magnitude performance improvement compared to unichannel (allocation at the connection level) allocation