Reliable and fast rerouting mechanism for a protected label switched path

We present a reliable, fast and efficient mechanism for rerouting traffic when there is a link/node failure or congestion problem in multiprotocol label switching (MPLS) networks. This proposal is able to guarantee rigorous QoS criteria for high-priority data traffic by eliminating packet loss and disorder, and minimizing packet delay. This directly translates into an improvement of important quality measure attributes, such as performance, reliability and fault tolerance, in MPLS-based networks. We use a predefined, alternative label switched path (LSP) in order to restore traffic (protection switching or fast rerouting). A theoretical model is formulated for the failure scenario in a protected LSP segment and we validate it through simulations using the MPLS network simulator (MNS). Further simulations show that our mechanism is able to eliminate packet loss and disorder completely while reducing the full restoration time. The potential cost in terms of the important issue of buffer requirements is also studied. Even for the worst case, buffer requirements are well within justifiable limits for guaranteeing QoS for high-priority data traffic in protected LSPs. The combination of these improvements helps to minimize the effects of link failure. This facilitates satisfying rigorous QoS requirements, increasing the throughput, rapid release of network resources and enhancement of the end-to-end performance of MPLS networks.