Exploiting the temporal dimension in QoS-aware multicast routing

In this paper, we propose to exploit the temporal dimension in dynamic QoS-based multicast routing to significantly improve the performance of previous spatial-oriented protocols while using less control overhead. We describe the design of a new protocol named TTBP (temporally correlated ticket-based probing), which is extended from a previous proposal TBP (ticket-based probing) protocol [IEEE J. Sel. Areas Commun. 17 (1999)] that uses a spatial-oriented directed search framework. T-TBP exploits the temporal dimension based on path caching and tree adjustment mechanisms to improve the quality of constructed multicast tree and probability of successful tree construction for member joins in a highly dynamic environment. The cached path information and tree adjustment mechanisms circumvent the major difficulties facing current greedy spatial-oriented approaches, and involve minimal additional overhead. Through extensive simulation, our proposal is demonstrated to achieve superior performance than the original protocol. Notably, it is able to construct lower-cost trees when network load is light, and to achieve higher probability of success for finding feasible path when network load is heavy. q 2002 Elsevier Science B.V. All rights reserved.