OPN08-03: Backup Path Re-optimizations for Shared Path Protection in Multi-domain Networks

Within the context of dynamic routing models for shared path protection in multi-domain networks, we propose a backup path re-optimization phase with possible rerouting of the existing backup paths in order to increase the bandwidth sharing among them while minimizing the network backup cost. The re- optimization phase is activated periodically or when routing a new connection fails because of insufficient capacity. Three re- optimization models are discussed: i) Global rerouting where the re-optimization is performed once for the entire network; ii) Local rerouting where the re-optimization is serially performed on one domain at a time or on selected domains, and iii) Local rerouting with least effort, i.e., where the smallest possible number of backup path reroutings is performed in order to be able to handle new connection requests. The first model offers the best resource savings while the two others are more scalable in multi-domain networks. Comparative performance of the three models are conducted and numerical results are presented.