One of the requirements for TE is the capability to reroute an established TE tunnel under various conditions. Such rerouting capabilities could include the following:
Setting administrative policies to allow the LSP to reroute, such as when the LSP does not meet QoS requirements.
Rerouting an LSP upon failure of a resource along the TE tunnel's established path.
Setting an administrative policy that might require that an LSP that has been rerouted must return to its original path when a failed link or router becomes available.
Network operation must not be disrupted while TE rerouting is in progress. This means that you need to establish backup tunnels ahead of time and transfer traffic from the old tunnel to the ...