A hierarchical restoration scheme with dynamic adjustment of restoration scope in an MPLS network

The paper proposes a hierarchical restoration scheme that can be applied to the restoration of working label switched paths (LSPs) and pre-provisioned backup LSPs. Our hierarchical restoration scheme is composed of two subsequent algorithms, one to determine the reasonable restoration scope (RS) and the other to compute an optimal alternative path that avoids the fault location. The first algorithm for dynamic RS determination increases the restoration speed by minimizing the complexity of the network topology for restoration as soon as possible. By increasing the reusability of the existing path, we can minimize the length of the new alternative path. In addition, the newly proposed concept of the hierarchical RS extension minimizes the probability of restoration failure by dynamically widening the restoration scope until the RS is equal to the whole network topology. Through simulation, we evaluate the performance of our restoration scheme and existing protection schemes (Huang, C. et al., 2000; Haskin, D. and Krishnan, R., 2000) in terms of the restoration speed, packet loss, network resource utilization, and resource reusability of the existing working LSP.