Impact of Traffic Predictability on WDM EXC/OXC Network Performance

Recently several investigations in the field of multilayer traffic engineering (TE) mainly focusing on random traffic demands have been carried out. In this paper, we propose different TE strategies for EXC/OXC networks including electrical traffic grooming and lightpath rerouting. Unlike existing investigations that consider only random demands for TE, we consider simultaneously scheduled and random traffic demands. Scheduled demands correspond to guaranteed services whereas random demands correspond to best-effort services. In order to outline the impact of traffic predictability on TE efficiency, we introduce the new concept of semi-random traffic demand that corresponds to random demands with predictable holding time. For a given network and a given traffic scenario, numerical simulations outline the huge gap between the rejection ratio of random demands and that of semi-random demands. In order to improve the rejection ratio of random demands, we propose to proceed for such demands to a time limited resource reservation (TLRR). The choice of the value of reservation window Delta strongly depends on the arrival and life duration processes of random demands. We show that it is possible to achieve comparable rejection ratios for both random and semi-random demands