A distributed algorithm for path restoration in circuit switched communication networks

Path restoration is an important approach for building survivable telecommunication backbone networks. Path restoration is known for high restoration efficiency and its ability to protect against single link, multiple link and node failures. Path restoration can be formulated as the well-known multi-commodity network flow (MCNF) problem. While many centralized algorithms have been proposed for solving the MCNF problem, distributed algorithms have received very little attention. This paper presents an online distributed multi-commodity flow approximation algorithm specifically tailored for path restoration. Our algorithm uses O(|E|diam²) messages and O(diam²) time in the worst case, and substantially fewer messages and less time in practical networks. When simulated on a sample real-life backbone network similar to those used by the telecommunication service providers, our algorithm finds a solution significantly faster than many published algorithms.