End-to-End Protection Switching Mechanisms for MPLS Networks

In this paper we propose and investigate several end-to-end (e2e) protection switching mechanisms with application in Multiprotocol Label Switching (MPLS) networks. In case of local outages, the traffic of affected paths is switched to other e2e paths. In this case, Quality of Service can only be provided if sufficient extra capacity is available on the backup paths. If backup capacity can be shared among different backup paths, multi-path routing allows for considerable savings regarding this extra capacity. We propose simple e2e backup mechanisms based on multi-path routing and optimize the load balancing by polynomial-time algorithms to minimize the extra capacity. The mechanisms are simple because the multi-paths consist of disjoint paths that are easy to configure and only traffic of failed paths is switched onto backup paths. Our results illustrate that the savings potential depends on the network topology and that 20% additional resources are sufficient for full resilience against all single router and link failures in well designed networks.