On line routing of guaranteed bandwidth with restoration

In this paper the problem of finding a pair of link (node) disjoint active Label Switched Path (LSP) and backup LSP in Multi Protocol Label Switching (MPLS) networks is considered. It was assumed that capacity on the links of the backup Label Switched Paths can be shared. We focus on online algorithms for routing of guaranteed bandwidth of active LSPs and backup LSPs under partial information model in order to optimize the total amount of bandwidth consumed in the MPLS network. We consider only the case of protection against single link (node) failure. In this paper the comparison of two known routing algorithms was carried out. The first of them is based on Integer Linear Programming [3, 4]. The second one is based on active-path-first heuristics [8]. In order to avoid the trap-problem the concept of Conflicting Link Set is used. Moreover, new algorithm based on active-path-first heuristics was proposed too. In this paper special attention has been paid to bandwidth consumed in the network, number of rejected connection set-up requests and running time of considered algorithms. The obtained results have proved that the proposed algorithm is comparable to the other algorithms but it has shorter running time then the existing ones.