A virtual overlay backup network is established to provide Fast Reroute
capability with guaranteed bandwidth protection to a network that employs
end-to-end circuits such as label switched paths (LSPs). In some
implementations, backup bandwidth is allocated from an available backup
bandwidth pool, as defined herein, available on each link. Complete
bandwidth protection may be provided rapidly upon detection of a failure
while available backup bandwidth is shared between independent failures.
In one embodiment, this is accomplished by provisioning backup tunnels to
protect all links and nodes, wherein total available backup bandwidth on
any link is not exceeded by the requirements of backup tunnels protecting
any single node but backup tunnels protecting different nodes may share
bandwidth.