Protection scheme for a communications network under multiple failures
A system and method for implementing a shared protection scheme under a scenario of multiple failures in an optical network. In one embodiment of the invention, a working path between an ingress node and an egress node is computed responsive to a connection request received in the network. One or more backup paths are computed between the ingress and egress nodes, which are activatable upon a failure condition associated with the working path or the backup paths. The backup paths may be based on link and/or node disjointedness, as well as resource-based cost constraints.
1. A method for providing protection in a communications network including a plurality of nodes coupled by communication links, comprising:
responsive to a connection request received by an ingress node, computing a working path between said ingress node and an egress node;
monitoring a quality of the nodes and the communication links;
detecting a first quality degradation event indicative of a failure prediction of one of the nodes or one of the communications links;
responsive to detecting the first quality degradation event, monitoring at least one of a temporal or spatial correlation of further possible quality degradation events with respect to the detected first quality degradation event to be able to detect a second quality degradation event indicative of another failure prediction of another one of the nodes or another one of the communication links; and
responsive to detecting the second quality degradation event, computing a plurality of backup paths between said ingress and egress nodes where the nodes and/or the communication links associated with the first and second quality degradation events are not used in a same backup path.
2. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said working path between said ingress node and said egress node is computed based on a Shortest Path First (SPF) algorithm.
3. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths are computed recursively until a predetermined number of backup paths is reached with respect to said working path.
4. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths comprise paths that are completely link-disjointed with respect to one another.
5. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths comprise paths that are partially link-disjointed with respect to one another.
6. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths comprise paths that are completely node-disjointed with respect to one another.
7. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths comprise paths that are partially node-disjointed with respect to one another.
8. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths comprise paths that are completely link-disjointed with respect to said working path.
9. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths comprise paths that are partially link-disjointed with respect to said working path.
10. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths comprise paths that are completely node-disjointed with respect to said working path.
11. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said backup paths comprise paths that are partially node-disjointed with respect to said working path.
12. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said working path and said backup paths are computed based on a cost parameter associated with said communication links, said cost parameter operating to penalize communication links that disallow sharing of paths.
13. The method for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 1 , wherein said working path and said backup paths are computed based on a prior-use cost parameter associated with said communication links, said prior-use cost parameter operating to penalize communication links that are already used.
14. A communication network including a plurality of nodes coupled by communication links, comprising:
a quality monitor that monitors a quality of the nodes and the communication links;
an ingress node, responsive to a connection request, that computes a working path between itself and an egress node;
said quality monitor further detects a first quality degradation event indicative of a failure prediction of one of the nodes or one of the communications links;
said quality monitor, responsive to detecting the first quality degradation event, monitors at least one of a temporal or spatial correlation of further possible quality degradation events with respect to the detected first quality degradation event to be able to detect a second quality degradation event indicative of another failure prediction of another one of the nodes or another one of the communication links; and
said ingress node, responsive to the detection of the second quality degradation event, computes a plurality of backup paths between said ingress and egress nodes where the nodes and/or the communication links associated with the first and second quality degradation events would not be used in a same backup path.
15. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said working path between said ingress node and said egress node is computed based on a Shortest Path First (SPF) algorithm.
16. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths are computed recursively until a predetermined number of backup paths is reached with respect to said working path.
17. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths comprise paths that are completely link-disjointed with respect to one another.
18. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths comprise paths that are partially link-disjointed with respect to one another.
19. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths comprise paths that are completely node-disjointed with respect to one another.
20. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths comprise paths that are partially node-disjointed with respect to one another.
21. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths comprise paths that are completely link-disjointed with respect to said working path.
22. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths comprise paths that are partially link-disjointed with respect to said working path.
23. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths comprise paths that are completely node-disjointed with respect to said working path.
24. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said backup paths comprise paths that are partially node-disjointed with respect to said working path.
25. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said working path and said backup paths are computed based on a cost parameter associated with said communication links, said cost parameter operating to penalize communication links that disallow sharing of paths.
26. The communication network for providing protection in a communications network including a plurality of nodes coupled by communication links as set forth in claim 14 , wherein said working path and said backup paths are computed based on a prior-use cost parameter associated with said communication links, said prior-use cost parameter operating to penalize communication links that are already used.
27. A network element disposed as an ingress node in an optical network formed from a plurality of nodes that are inter-coupled via optical communication links, said ingress node including a computer readable medium having a plurality of instructions which when executed by a computer cause said ingress node to perform operations comprising:
computing a working path between said ingress node and an egress node;
upon receiving an indication that at least two quality degradation events having at least a temporal or spatial correlation with respect to one another have occurred which are indicative of a failure prediction of one or more of the nodes or one or more of the communications links, computing a plurality of backup paths between said ingress and egress nodes where the nodes and/or the communication links associated with the at least two quality degradation events are not used in a same backup path.
28. The network element as set forth in claim 27 , wherein said instructions for computing said working path include instructions for determining a working path between said ingress node and said egress node based on a shortest path first algorithm.
29. The network element as set forth in claim 27 , wherein said instructions for computing said backup paths include instructions operable to determine multiple backup paths using a methodology in which said backup paths are completely link-disjointed with respect to one another.
30. The network element as set forth in claim 27 , wherein said instructions for computing said backup paths include instructions operable to determine multiple backup paths using a methodology in which said backup paths are completely node-disjointed with respect to one another but for said ingress and egress nodes.
31. The network element as set forth in claim 27 , wherein said instructions for computing said backup paths include instructions operable to determine multiple backup paths using a methodology in which said backup paths are partially node-disjointed with respect to one another but for said ingress and egress nodes.
32. The network element as set forth in claim 27 , wherein said instructions for computing said backup paths include instructions operable to determine multiple backup paths using a methodology in which said backup paths are partially link-disjointed with respect to one another.
33. The network element as set forth in claim 27 , wherein said instructions for computing said backup paths and said working path include instructions operable to calculate paths based on a cost parameter associated with said communication links, said cost parameter operating to penalize communication links that disallow sharing of paths.
34. The network element as set forth in claim 27 , wherein said instructions for computing said backup paths and said working path include instructions operable to calculate paths based on a prior-use cost parameter associated with said communication links, said prior-use cost parameter operating to penalize communication links that are already used.