Routing in optical mesh networks

Routing is a key control and operational aspect of optical mesh networks.

In transparent or all-optical networks, routing of connections is tightly linked to the wavelength selection and assignment process (so-called routing and wavelength assignment, or "RWA"). This is due to the fact that the connection remains on the same wavelength from end-to-end throughout the network (sometimes referred to as wavelength continuity constraint, in the absence of devices that can translate between wavelengths in the optical domain). In an opaque network, the routing problem is one of finding a primary path for a connection and if protection is needed, a backup path diverse from the primary path. Wavelengths are used on each link independently of each other's. Several algorithms can be used to determine a primary path and a diverse backup path (with or without sharing of resource along the backup path) for a connection or service, such as shortest path, including Dijkstra's algorithm, k-shortest path, edge and node-diverse or disjoint routing, including Suurballe's algorithm, and numerous heuristics.

July 19, 2011

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