Abstract:

The V-PREPT（Versatile Preemption) algorithm only concerns with minimizing the total cost of preemption leaving out the number of LSPs（Label Switching Paths) to be preempted, leading to excessive number of rerouting decisions. In this paper, an algorithm providing utilization rate of network resources and QoS（Quality of Service), named N-PREPT is proposed. The N-PREPT algorithm executes the preemption of LSPs according to the main preemption optimization criteria, under the premise of minimizing the total cost of preemption. It considers minimizing number of LSPs to be preempted and avoiding the occurrence of cascading preemption at first and uses hierarchical approximation method to raise restriction to the number of preemption. Simulation results show that the proposed algorithm significantly outperforms the V-PREPT algorithm when preemption occurs in the network.

Key words: differentiated services(DiffServ), traffic engineering, preemption algorithm, N-PREPT algorithm, label switching path