An efficient hybrid recovery mechanism for MPLS-based networks

This paper proposes an improvement to the IETF (Internet Engineering Task Force) standard intra-domain recovery mechanisms based on a combination of the existing IETF standards. The proposed mechanism defines a new fast recovery process that ensures efficient resource utilization. Since the IETF protection switching mechanism follows a pre-planned approach, i.e., it selects a backup path only once at the LSP (Label Switched Path) setup time, it may not reflect the exact status of network resources at the time of a fault. Moreover, backup path computation may infer unsolicited delay before an available backup path can be selected. The proposed solution combines the pm-planned protection switching mechanism with an on-line computation of an available backup path that may be closer to the failing point. The backup path computation is ensured by an efficient and fast engine based on up-to-date network state and capability to support the required Forwarding Equivalence Class (FEC). Once found, a safe transition from protection model to the new backup path is performed. Simulations results prove that the proposed mechanism is able to ensure and maintain an optimized network state regardless of the fault occurrence.