Patent ID: 9461909
Filing Date: 2016-10-04
CPC Classification: H04L

Claim Text:
1. A method to forward Ethernet frames at a node in a network supporting an implementation of shortest path bridging (SPB) protocol, wherein the node contains a filtering database (FDB) to guide Ethernet frame forwarding, wherein the FDB update is coordinated through a digest exchange between the node and one or more nodes of a plurality of neighboring nodes, the method comprising: starting a shortest path computation for the node, the shortest path computation selecting a shortest path from the node to a destination node in the network, wherein a neighboring node of the plurality of neighboring nodes that is on the shortest path is recorded; computing a loop-free alternate (LFA) node for an alternate path to reach the destination node, wherein the LFA node is one of the plurality of neighboring nodes and is closer to the destination node than the node, but not on the shortest path, and the node has an existing database digest agreement with the LFA node, wherein the LFA node has a set of permissible ports that link to an upstream node or nodes to receive unicast Ethernet frames, such that the set of permissible ports indicates that the Ethernet frame forwarding from the upstream node or nodes to the destination node through the LFA node is known not to cause a forwarding loop; and forwarding, from the node, a unicast Ethernet frame with a destination media access control (MAC) address corresponding to the destination node through the LFA node without computing another shortest path computation that removes the neighboring node, when connectivity to the neighboring node on the shortest path to the destination node is detected to be in an abnormal state for use in forwarding the unicast Ethernet frame, wherein the LFA node relaxes reverse path forwarding check (RPFC) and accepts the unicast Ethernet frame from the node, when the node is linked to the LTA node via one of the set of permissible ports.