Abstract:

There exists a waste of bandwidth resources due to the heuristic algorithms for the preemption in multiprotocol label-switching （MPLS） networks. In order to solve this problem, the preemption policy for the Diffserv- Aware Traffic Engineering in MPLS networks is analyzed and an optimized heuristic algorithm is proposed based on three main preemption optimization metrics, namely the number of label-switched paths （LSPs） to be preempted, the preemption priority of LSPs and the preemption bandwidth. The proposed algorithm, marked as B-PREPT （ Backtracking Preemption）, employs the backtracking method to solve the nondeterministic polynomial （NP） -complete problem. Simulated results indicate that, as compared with the well-known heuristic algorithm V-PREPT （Versatile Preemption）, the proposed algorithm is of lower cost, higher accuracy and almost equal efficiency. Thus, it is applicable in actual networks. A path selection scheme based on the preemption policy is also investigated .

Key words: traffic engineering, multi-protocol label-switching network, preemption, heuristic algorithm