Research On MPLS Fault Restoration

With the rapid development of computer network technology during the last few years, More and more kinds of traffic are transmitted in the Internet, and the demands of the traffic with QoS are enhanced. The traditional IP network architecture can seldom cope with the demand of bandwidth and transmimssion speed. The MPLS technology has solved this issue. The MPLS mechanism can transmit the traffic with high speed, and MPLS Traffic Engineering does well in using the network resources sufficiently, optimizing the performance of networks, reducing the probability of network congestion. MPLS can guarantee the QoS demand.As an important part of MPLS architecture, MPLS restoration technology has been the hot spots. Based on studying the architecture of MPLS and MPLS TE, this paper learns the principle and stagety of MPLS restoration, and proposed two MPLS restoration scheme and algorithm.Protection switching is an important method of MPLS restoration, and it can provide reliable end-to-end path protection. This paper studies two classic schemes called Haskin scheme and Fast Rerote scheme, based on which we propose an improved scheme called NHF scheme. NHF scheme integrated the golobal repair and local repair together, which could lower the delay of golobal repair and redude the number of reluctant paths made by loaol repair. This paper simulates NHF scheme with NS2 and compares the performances of Haskin Scheme and FRR scheme. The experiment result indicates that NHF scheme had low ene-to-end delay. It could reduce the rate of packet disordering and enhance the network throughput.Rerouting is another important kind of MPLS restoration method. Rerouting can provide fast responsing period and flexible restoration scheme, but it strongly demands the performance of routing algorithm to choose the best path. With learing the simulated annealing algorithm and Tabu search algorithm, we propose a rerouting algortithm based on the intellect srarching algorithm called NRRA. NRRA uses the method of SA algorithm and introduces the Tabu table.NRRA can choose the best path in the network and repeats this process when faults appear in the network. This article implenment NRRA with VC 6.0 and calculated the performance and the restoration time of NRRA. The experiment results had shown that NRRA could find the best path with fast algorithm convergence and low reaotration period.