Abstract
To alleviate the impact of network component failures, many fast IP local recovery schemes have been proposed to reroute traffic in the event of failure. Tunnel-based fast IP local recovery is one of the most commonly adopted techniques. In IP-in-IP tunneling, when a failure occurs, the nodes adjacent to a failure are activated to encapsulate and reroute the affected traffic to the endpoint along the shortest path. Once the endpoint receives the affected traffic, it décapsultes and delivers the packets to original destination along the shortest path. These shortest paths are computed based on link weights. Therefore the design of link weights for tunnel-based fast IP local recovery is a critical issue. The goal of this paper is to determine a set of link weights in a tunnel-based fast IP local recovery system to jointly achieve: (1) load balance in the normal state (i.e., non-failure state) and (2) protection of any single link failure without incurring link overload during the failure recovery. We first formulate this problem as a mixed integer programming (MIP). Due to the NP-hard property of the MIP, a Simulated Annealing based Tunneling (SATu) scheme is proposed to obtain the solution of the MIP. In SATu, only the nodes adjacent to a failure are activated to encapsulate the affected packets and forward them to endpoint without disturbing regular traffic. Numerical results show that the proposed scheme improves tunnel-based IP fast reroute approach to achieve high rate of fault recovery in protecting single link failures without incurring link congestion in the non-failure state. © 2011 IEEE.