Patent ID: 9301028
Filing Date: 2016-03-29
CPC Classification: H04J,H04L,H04Q

Claim Text:
1. A method for implementing alternative routes, comprising: distributing, by a managing plane, a constraining condition which comprises must-be-passed-through network resource and Shared Risk Link Group; dividing, by a Path Computation Element (PCE) of Wavelength Switched Optical Network (WSON), a to-be-computed complete route from a source node to a destination node into subsegments according to the must-be-passed-through network resource of the constraining condition distributed by a the managing plane; wherein the PCE is a path computing unit of GMPLS (Generalized Multiprotocol Label Switching) and the alternative routing is a function that PCE needs to process under block crossing conditions in WSON; computing, by the PCE, alternative sub-routes of each subsegment independently based on the constraining condition distributed by the managing plane; wherein said computing alternative sub-routes of each subsegment comprising: satisfying the constraining condition distributed by the managing plane and when computing alternative sub-routes of a subsegment, taking the source node and the destination node of the complete route as must-be-avoided network resources and taking the must-be-passed-through nodes as must-be-avoided network resources, except that a head node and a tail node of the subsegment are not taken as must-be-avoided network resources, and not taking intermediate nodes that are passed through by the alternative sub-routes of other subsegments as must-be-avoided network resource; and after the computation, screening and combining, by the PCE, the computed alternative sub-routes of each subsegment so that no repetitive node and no repetitive link exist within any one of the combined complete alternative routes; implementing, by the PCE, alternative routing based on the computed alternative routes; wherein said method is applied in an optical transmission network of the WSON for designing appropriate RWA (Routing and Wavelength Assignment) to realize SPC (Soft Permanent Connection).