Toward Shortest Backup Paths for IP Fast ReRoute

Abstract

The slow convergence under intra-domain link or router failures is a challenge for latency-sensitive applications in the IP networks. A variety of IP Fast Re-Route (IPFRR) schemes have been proposed to address the issue in the literature. Our paper reviews several of these IPFRR schemes: Loop Free Alternate, U-Turn Alternate, and in particular, NotVia addresses. Having observed issues caused by the selection of the end-points of backup tunnels in the NotVia scheme, we explored a variety of designs that improve NotVia by changing the end point of the tunnel. In particular, tunneling to the destination yields the shortest backup paths in the survived subgraph. However, it introduces significant increase of the routing table size, shedding light on the unbalanced trade-off between the length of the backup path and the routing table size.