Sticky 1+1 path protection method by dynamic disjoint path discovery

Our goal is to maintain 1+1 path protection as much as possible after a single failure occurs for ensuring carrier-grade reliability. An obvious approach is preparing a third path that is disjoint with the primary and backup paths, but applicability to actual networks with this approach is extremely restricted. From our evaluation, the recovery ratio for reconstructing 1+1 path protection decreases to 13-30% in the worst case. We propose a dynamic disjoint path discovery algorithm for possibly repairing 1+1 path protection. The dynamic path does not provide a path-disjoint but failed-link-disjoint path. The disjoint constraint is relaxed; therefore, our algorithm can provide a high recovery ratio to reconstruct 1+1 path protection. Our analysis identified the dominant elements for maintaining the high recovery ratio: the number of nodes whose node degrees are less than three and the distance between those nodes. This dynamic approach, which uses mature protocols, is applicable to various networks, and automatic preparation of the new backup path can reduce the OPEX.