A New Preemption Strategy with Re-routing Control for MPLS Networks

In this paper, we study the effects of preemption and re-routing on the performance of multi protocol label switching (MPLS) networks. MPLS with traffic engineering supports diversified quality of service (QoS) requirements and allows the setting up of explicit path through networks. Usually, traffic engineering is used to achieve load balancing where longer path may be used to route a connection to prevent part of the network from over-utilized. However, since a longer path needs more resources, this may increase the loss probability of a network. This is especially true if the connection routed is of high priority which cannot be preempted by future connections. We suggest that a high priority connection should always be routed on the shortest path to minimize the consumption of network resources. Preemption may be triggered to acquire the resources needed from the existing lower priority connections. The connections to be preempted can be re-routed to avoid the interruption of service. We introduce a new strategy to preempt the existing connections and control the re-routing process to avoid the explosion of re-routing process for a single preemption event. Finally, the simulation results show that the new strategy can limit the extent of re-routing process and improve the network performance significantly