System and method for finding partially disjoint paths for spare capacity allocation in shared backup path protection for dual fiber cuts

Abstract

System and method embodiments are provided herein to obtain minimum or optimal spare capacity allocation (SCA) using partial disjoint paths (PDP) for bi-connected network topology. Both an integer linear programming (ILP) optimization model and an approximation algorithm, referred to herein as Successive Survivable Routing (SSR), are formulated for resolving the SCA with PDP. The embodiments include assigning a working path and a primary backup path on two disjoint routes between two end nodes, and assigning a plurality of secondary backup paths that are partially disjoint and that each pass through one fiber cut group on one of the two disjoint routes and all remaining fiber cut groups on the other one of the two disjoint routes. Each of the fiber cut groups includes all fiber cut pairs on both disjoint routes that have the same effect of interrupting a flow on both disjoint routes.