Patent ID: 7406032
Filing Date: 2008-07-29
Classification: H04L,Y04S

Abstract:
1. A method comprising: in a network comprising a plurality of link-coupled nodes, at a non-terminal node located on a label switched path of a plurality of label switched paths in the network; selecting an optimized backup path for rerouting traffic around a failure located immediately downstream of the non-terminal node, wherein the failure is one of a plurality of possible failures on the plurality of label switched paths, the optimized backup path comprising a subset of the plurality of link-coupled nodes of the network; and for each predetermined link of a plurality of links along the selected optimized backup path, reserving a backup bandwidth, wherein each predetermined link is comprised in a respective plurality of backup paths, wherein the backup bandwidth is sufficient to reroute traffic around a single failure on one of the plurality of label switched paths, wherein the backup bandwidth is determined by a value of a plurality of values, wherein each value of the plurality of values corresponds to a bandwidth associated with a particular failure of the plurality of possible failures, the method further comprising: determining a link weight for use in said activity of selecting the optimized backup path, the link weight calculated according to: where: T[i]=max(Failself(DR)[i], Failself(DL)[i]); Failself(DR)[i] a necessary bandwidth on link i to reroute traffic associated with all label switched paths affected by the failure of DR; Failself(DL)[i] a necessary bandwidth on link i to reroute traffic associated with all label switched paths affected by the failure of DL; DR is the immediately downstream node of the non-terminal node along the label switched path; DL is a link between the non-terminal node and node DR; {DR} is a set of links adjacent to node DR; {DP} is a set of links between the non-terminal node and the destination node of the label switched path; R[i] is a bandwidth reserved for link i to reroute traffic responsive to a single failure in the network; b is the requested bandwidth of the label switched path; W[i] is a prior weight for link i; ε is a small, non-zero weight in favor of selection of link i; and w[i] is a modified weight associated with a link i.