On the performance of heuristic H MCOP for multi-constrained optimal-path qos routing

Network services for finding a feasible or an optimal path subject to multiple constraints on performance metrics such as delay, jitter, loss probability, etc. give rise to multipath-constrained (MCP) or multi-constrained optimal-path (MCOP) quality of service (QoS) routing problems, which are N P-complete. Heuristic algorithm H MCOP proposed by Korkmaz et al. has been widely recognized for its low time complexity and high probability of finding feasible solutions. In this paper, the performance of this heuristic is reinvestigated under several special cases. Simulation results indicate that in some cases its probability of finding feasible solutions is unexpectedly low. Such observation, which is further used to explain the performance of a heuristic based on H MCOP, would be of extreme importance when designing any higher-level QoS routing algorithms that need to use H MCOP to find feasible solutions. 1