State-of-the-art progress in developing survivable routing schemes in mesh WDM networks

This article introduces the state-of-the-art progress in developing survivable routing schemes in the optical layer of modern mesh WDM networks. Emphasis is placed on the requirements for achieving survivability that keep stringent service continuity for bandwidth provisioning under any unexpected failure of network infrastructure (e.g., a link, node, or device). We first review the reported dynamic survivable routing schemes that find the least-cost working and protection path-pair for both dedicated and shared protection. With the knowledge of shared risk link group (SRLG), we define the cost function and link-state for solving the protection path for a given working path. This article also discusses the survivable routing schemes for spare capacity allocation that deal with multiple working paths, in which both span-oriented and path-oriented spare capacity allocation schemes will be defined and discussed.