Detour Computations

Computing and setting up detours is done independently at each node. On a node, if an LSP has fast reroute enabled and if a downstream link or node can be identified, the router performs a CSPF computation using the information in the local traffic engineering database (TED). For this reason, detours rely on your IGP's supporting traffic engineering extensions. Without the TED, detours cannot be established.

Detour computations might not succeed the first time. If a computation fails, the router recomputes detours approximately once every refresh interval until the computation succeeds.