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US 7,406,032 B2Granted
Bandwidth management for MPLS fast rerouting
AssigneeAT&T Corp.
InventorsGuangzhi Li, Dongmei Wang
Life of this patent
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Abstract
Certain exemplary embodiments provide a method comprising: in a network at a node located on a label switched path: selecting a backup path to respond to a failure; and for each link along the backup path, reserving a backup bandwidth, wherein the backup bandwidth is sufficient to reroute traffic around the failure.
Claims1
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:
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- 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.
129 more elements
Dependencies are inferred from the claim text.