Optimal recovery LSP design scheme for fast reroute methods

摘要

We propose the optimal recovery LSP design scheme for the MPLS LSP fast reroute methods. In the fast reroute methods, a node that detects a failure switches a primary LSP to a recovery path, and recovery LSPs are pre-established. Therefore, (N-1) recovery LSPs must be established per a primary LSP of hop N. The number of recovery LSPs will be large, so it is important to share resource for recovery LSPs as much as possible. We formulated recovery LSP design problems with three approaches: 1) shared over a network, 2) shared over recovery LSPs of the same primary LSP, 3) dedicated, as Integer Programming problem. Numerical evaluation showed the network designed by the shared over a network approach can accommodate more than double traffic demand than that by the dedicated approach, and sharing resources of recovery paths is essential.