An efficient recovery mechanism for MPLS-based protection LSP

Network reliability and survivability have been very important issues to provide for application services that may require a real-time service or high priority QoS (quality of service) in the Internet. IETF has proposed largely two recovery mechanisms for MPLS-based protection label switching path (LSP), which are protection switching and rerouting models. However, from the viewpoint of TE (traffic engineering), IETF's recovery mechanisms have not considered the optimal backup path for the recovery of an LSP in the occurrence of a network failure. This paper suggests an efficient pre-qualified recovery mechanism, which optimizes the network performance by considering link usage. Since an existing recovery mechanism, pre-qualified rerouting, selects a backup path only once at the LSP setup time, it may not reflect the exact status of network resources at the time of a fault. In contrast, our approach exchanges network status information among LSRs so that the backup path selection engine can use up-to-date information and decide an optimal backup path for a possible failure. The performance of the proposed recovery method has been demonstrated by simulation using MNS (MPLS network simulator). The new proposed recovery mechanism can always maintain an optimized network state regardless of the fault occurrence.