×

Enhanced procedure to compute LFAs with IGP max metric

  • US 9,407,534 B2
  • Filed: 05/27/2014
  • Issued: 08/02/2016
  • Est. Priority Date: 05/27/2014
  • Status: Active Grant
First Claim
Patent Images

1. A method implemented by a network device in a network having a plurality of nodes, the method to calculate a loop free alternative (LFA) next hop as a backup for a next hop of a primary path for an interior gateway protocol (IGP), where the method enables consideration of the LFA next hop where a link to the next hop has a reverse cost that has a maximum value, where the maximum value is a maximum link metric defined for the network, a forward cost is a metric for an outbound direction from the network device on the link, the reverse cost is a metric for an inbound direction toward the network device on the link, the method comprising the steps of:

  • selecting a next candidate next hop from a set of candidate next hops in the network;

    checking whether a link to the next candidate next hop is an administratively allowable link;

    checking whether the link has a maximum forward cost, where the maximum forward cost is a value defined for the network as a maximum possible value for a forward link cost;

    checking whether the link is bi-directional;

    computing LFA using the next candidate next hop where the link is administratively allowable link, where the link does not have the maximum forward cost, where the link is bi-directional, and where the link is considered for the LFA when the link has a reverse cost with the maximum value; and

    updating a local routing information base of the network device to enable forwarding of data traffic using the computed LFA where the primary path has failed.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×