Survey of Recovery Schemes in MPLS Networks

To provide dependable services MPLS networks make use of a set of procedures (detection, notification and fault recovery) which seek to ensure appropriate protection for the traffic carried in the LSPs. When a fault happens in the active LSP, the recovery scheme must redirect the traffic to a recovery path (the protection LSP or recovery LSP) which bypasses the fault. The two basic recovery models used to redirect traffic are rerouting and protection switching. Protection switching is faster than rerouting but cannot handle simultaneous faults in the active and the recovery path. On the other hand, rerouting is generally slow, and cannot offer QoS guaranties upon failure, but can use resources in a more efficient way. In this work we present a survey of several fault recovery schemes, firstly some approaches for protection switching is review and secondly the characteristics of some rerouting approaches is discuss. For these schemes, we also allude to the extensions required by the signalling and traffic engineering routing protocols. Finally, the reviewed recovery mechanisms are classified according to a set of characteristics considered relevant