An Efficient Recovery Mechanism for MPLS-based Protection LSP for Network Reliability and survivability

Network reliability and survivability have been very important issues to provide application services that my require a real-time service or high priority QoS (Quality of Service) in Internet. IETF has proposed largely two recovery mechanisms (Protection Switching and Rerouting) for MPLS-based protection LSP, to support reliable and survivable network services in the occurrence of a network failure. However, in the viewpoint of TE (Traffice Engineering), IETF's recovery mechanisms have not considered efficient used of network resources for the recovery of LSP. This paper suggests an efficient pre-qualified recovery mechanism, which optimizes the network performance by considering several parameters, such as path hop count, link usage rate, delay, and resource usage etc. 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 the fault. On the contrary, our approach exchanges network status information among LSRs periodically so that the backup path decision engine can used up to date information and maintain 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 a stabel and optimized network state regardless of the fault occurrence.