HITLESS RECONFIGURATION OF A WAVELENGTH DIVISION MULTIPLEXED OPTICAL COMMUNICATION NETWORK

A method of reconfiguring a multi-wavelength communication network. The transition includes determining the union of the old and new topologies. During at least the start of the transition, the network supports the union topology. New connections are connected according to the new topology, and the old topology, as its connections expire, is gradually removed. In allocating wavelengths to a new topology, two algorithms are developed which assign wavelengths which do not color clash with the wavelength assignments of the old topology.