Fault tolerance method for any set of simultaneous link faults in dynamic wdm optical networks with wavelength continuity constraint

A computer implemented method for conferring fault tolerance to a dynamic wavelength division multiplexing (WDM) optical network having wavelength continuity constraints, CHARACTERIZED in that it comprises the steps of:

• obtaining, by means of a computational device, a topology of said network, wherein said network is represented by a graph =(, ) comprised of a set, , of nodes interconnected by a set, , of links;
• obtaining, by means of said computational device, a set of users of said network, wherein a user is defined as a pair of nodes, source and destination, and a traffic load associated with said user;
• obtaining, by means of said computational device, a set of primary routes, each primary route corresponding to a user, and a set of capacities, each capacity corresponding to a link of said set of links;
• obtaining, by means of said computational device, a failure scenario, said failure scenario corresponding to a subset of links or nodes in failed state;
• generating, by means of said computational device, a second topology corresponding to the topology of said network in which the links in failed state, corresponding to said failure scenario, are removed;
• calculating, by means of said computational device and for each user of said network whose primary route uses any of said links in failed state, corresponding to said failure scenario, a new cheaper route;
• and
• storing, by means of said computational device, said cheaper routes as secondary routes, corresponding to said set of users in said failure scenario, in a database;
• wherein said step of calculating by means of said computational device said cheaper route comprises the steps of:
• selecting, by means of said computational device, one of said users whose primary route uses any of the links in failed state;
• calculating, by means of said computational device, a cost for each link in said new topology, said cost being defined as the sum of the traffic loads of the primary routes using said link and the traffic loads of the secondary routes using said link;
• obtaining, by means of said computational device, a new cheaper route for said selected user, using said new topology and the costs of each link;
• and
• repeating the above steps until a cheaper route has been obtained for all users whose primary route uses any of the links in failed state.