Research On Shared Path Protection Strategy And Algorithm Based On SRLG-disjoint

With the development of information technology, especially the strong promotion by the Internet to traffic increment, new and higher requirements of the modern optical network are needed. Then the automatically switched optical network (ASON) was proposed. Through the introduction of control plane and combination with the generalized multi-protocol label switching (GMPLS), ASON provides rapid fault recovery capabilities for the optical network. This becomes the key function demand and advantage of ASON. Protection and recovery become those of important technologies to guarantee the optical network. So they become the hot spot in the field.Shared risk link groups are the links shared with the same physical resources. The links in the same SRLG have the same risk to be failed. The protection algorithm based on SRLG is to find a couple of routes--one for work and one for protection--satisfied with the constraint of SRLG. When the work route is failed, the protection route transforms the information instead of the work route. But we can't always find a couple of routes completely SRLG-disjointed. Thus differentiated reliable partial SRLG-disjoint algorithms or best effort SRLG algorithms are needed. Protection algorithm should also give due consideration to the resource sharing and load balancing so as to make the best use of the network resource. Considering all above, the shared path protection algorithm based on reliability(SPBR) is proposed. SPBR algorithm gives different ways to calculate the back path in connection with different reliability requirements. Before computing work path and back path, the algorithm will judge whether the link request need 100% protection. If the link request needs 100% protection, it will compute the work path and back path according to complete SRLG-disjoint; else it wll use best effort SRLG-disjoint scheme to calculate work path and back path. The two schemes all consider the load balance and resource shared. Finally, this paper simulated SPBR algorithm in GLASS based on single SRLG failure condition. Simulation results indicate that, compared with the special protection DP and traditional SRLG-disjoint algorithm KSP-SRLG, SPBR algorithm can reduce blocking probability, and improve the network resource utilization on the premise of satisfying the reliability requirements.