P-LFA: A Novel LFA-Based Percolation Fast Rerouting Mechanism

Abstract

Loop Free Alternate (LFA for short) is designed to avoid the interruption of transmission paths during routing convergence when a network suffers from single point failures (e.g. node failure, or link failure). Unfortunately, once more than one associated failure occurs simultaneously, the LFA protocol cannot strictly guarantee lossless packets. Therefore, we propose a LFA-based percolation routing mechanism (P-LFA for short). It establishes the shortest paths and their backup paths by using distributed routing protocol and LFA, and uses a percolation rerouting algorithm to calculate the percolation paths. Once the shortest path and corresponding backup path are interrupted, the network node immediately selects the percolation paths to continue transmitting packets without dropping any packets. And this mechanism allows each node to cache packets. This way can efficiently avoid packet loss when the path to the destination node is unreachable. The experimental results show that P-LFA can effectively guarantee zero-loss packets when some related failures occur. Meanwhile, even though there do not exist reachable paths to the destination node, the P-LFA mechanism can cache unreachable packets into the network node that is the closest to the destination node, and continue to re-forward packets when paths recover.