New approaches to service restoration in MPLS-based networks

Multiprotocol label switching (MPLS) has emerged as the technology of choice for future IP networks. As the demands put on networks increase, MPLS can serve as the basis for providing better reliability, manageability, and overall quality of service. This paper proposes a new approach to service restoration in MPLS networks based on the concept of domain protection, where protection of paths leading from all ingress routers to a common egress router is calculated in one step. The scheme allows a flexible protection path placement independent of the working path placement. Protection paths are calculated using an algorithm with low polynomial complexity. We discuss a mechanism for switching over to the protection paths after a failure is detected. It ensures faster switching time, minimal loss and packet re-ordering. A simulation study is used to evaluate the benefits of the proposed scheme and to compare it with two recently proposed schemes for MPLS restoration: RSVP (resource reservation protocol) backup tunnels and fast reroute. The results show that the proposed scheme provides a better solution than the fast reroute scheme and comparable protection to the RSVP backup tunnels while exhibiting lower algorithmic complexity. Unlike the proposed scheme, both fast reroute and RSVP backup tunnels require simultaneous calculation of working and protection paths in order to guarantee a link disjoint placement.