Usage Scenario
On a network with the mLDP MBB capability enabled, if mLDP FRR is disabled and an upstream node detects an outbound interface failure, this node delays the deletion of the primary entry because failing to converge to a new outbound interface and delivers an mLDP FRR entry over the direct IGP route to the downstream node so that multicast traffic is directed to the downstream node along a P2MP LSP. During the preceding process, a best-effort path is established to protect traffic on the link to the faulty outbound interface, which helps improve route convergence and reduce traffic loss.
Prerequisites
mLDP P2MP has been enabled globally using the mldp p2mp command.