Virtual links may be used to divert traffic within an
Ethernet network without affecting overall traffic patterns on the
Ethernet network. In one embodiment, the
virtual link may be established on the network via a routing
system in use on the network. Nodes on a defined path for the
virtual link will install forwarding state for the
virtual link so that traffic may follow the defined path through the network. The
logical view of the virtual link, from a routing perspective however, has the same cost as the shortest path between the endpoints of the virtual link and, accordingly, does not affect other traffic patterns on the network. Once established, the end nodes on the virtual path will have two equal cost paths through the network—one following the
shortest path tree and one along the path for the virtual link. The end nodes may use a tie breaking process in an Equal Cost
Multi Path (ECMP) selection process to preferentially select the virtual link over the shortest path.