Patent ID: 8243586

Claim:
A method for reconfiguring a pre-computed multiprotocol label switch fast reroute backup path b (x,y) of a second network link (x,y) from head-end node x to node y, after failure of a first network link l, the method comprising: receiving at the head-end node x of the second link (x,y), from a head-end node of the first link l, a link state advertisement indicating decreased capacity on links along a backup path b l of the failed first network link l; determining at the head-end node x that the second link (x,y) is an impacted link, by determining that the pre-computed multiprotocol label switch fast reroute backup path b (x,y) of the second network link includes a link contained in the backup path b l of the failed first network link l; at the head-end node x, in response to determining that the backup path b (x,y) of the second network link (x,y) includes a link contained in the backup path b l of the failed first network link l, computing a new shortest path from node x to node y, ignoring links l, (x,y), and links common to b (x,y) and b l ; and in response to determining that the backup path b (x,y) of the second network link (x,y) includes a link contained in the backup path b l of the failed first network link l, replacing the pre-computed multiprotocol label switch fast reroute backup path b (x,y) with the new shortest path.