Patent ID: 7477843

Claim:
A method of selecting an optically viable path through which to route a connection from a first node to a second node of a photonic network, the method comprising: selecting a plurality of optically viable photonic paths in the photonic network, at least one of the optically viable photonic paths comprising a plurality of consecutive optical links; selecting a path from the first node to the second node taking account of the plurality of optically viable photonic paths as at least part of the topological context when selecting the path wherein the step of selecting a plurality of optically viable photonic paths comprises passing data identifying a first possible path in the photonic network to an optical viability checking function; in response, receiving data indicating a measure of optical viability of the first possible path from the optical viability checking function; and determining whether to include the first possible path in the plurality of optically viable photonic paths in dependence on the received data.