A Queueing Model Framework of PCE-based Inter-area Path Computation

Path computation elements (PCE's) are used to compute end-to-end paths across multiple areas. Multiple PCE's may be dedicated to each area to provide sufficient path computation capacity and redundancy. An open problem is to which PCE to send the path computation request. This problem may be a non trivial problem if PCE's have uneven processing capacities. This paper presents a queueing model based on product form to estimate the latencies in path computation while accounting for the arrival rate of path computation requests. The model is used to find the PCE selection policy to minimize the overall expected latencies in path computation. Simulation studies demonstrate that the use of the simplistic product form approach yields reasonable approximations that are within up to 15% of the simulation results at practical offered loads.