Multi-constrained routing based on simulated annealing

Multi-constrained quality-of-service routing (QoSR) is to find a feasible path that satisfies multiple constraints simultaneously, as an NPC problem, which is also a big challenge for the upcoming next-generation networks. In this paper, we propose SA_MCP, a novel heuristic algorithm, by applying simulated annealing to Dijkstra's algorithm. This algorithm first uses a nonlinear energy function to translate multiple QoS weights into a single metric and then seeks to find a feasible path by simulated annealing. The paper outlines simulated annealing algorithm and analyzes the problems met when we apply it to QoSR. Extensive simulations demonstrate that SA_MCP has good scalability regarding both network size and the number of QoS constraints with high performance. Furthermore, when most QoS requests are feasible, the running time of SA_MCP is about O(k(m+nlogn)), which is only k times that of the traditional Dijkstra's algorithm, where k is the number of QoS constraints. Keywords-Simulated annealing, energy function, QoS routing, multiple constraints, scalability