Description: When the value of vRtrMplsLspFastReroute is 'true', fast reroute is enabled. A pre-computed detour LSP is created from each node in the primary path of this LSP. In case of a failure of a link or LSP between two nodes, traffic is immediately rerouted on the pre-computed detour LSP thus avoiding packet loss. Each node along the primary path of the LSP tries to establish a detour LSP as follows: Each upstream node will setup a detour LSP that avoids only the immediate downstream node and merges back onto the actual path of the LSP as soon as possible. The detour LSP may take one or more hops (upto the value of vRtrMplsLspFRHopLimit) before merging back onto the main LSP path.

When the upstream node detects a downstream link or node failure, it immediately send traffic for that LSP on the detour path and at the same time signals back to the ingress ESR about the failure.

Fast reroute applies only to the primary path of this LSP. No configuration is required on the transit hops of the LSP. The ingress ESR will signal all intermediate ESRs using RSVP to setup their detours.

When the value of vRtrMplsLspFastReroute is 'false', fast rerouting is disabled.