MVPN upstream PE or P node fast failover detection method is supported with RSVP P2MP I-PMSI only. A receiver PE achieves fast upstream failover based on the capability to subscribe multicast flow from multiple UMH nodes and the capability to monitor the health of the upstream PE and intermediate P nodes using an unidirectional multi-point BFD session running over the provider tunnel.
A receiver PE subscribes multicast flow from multiple upstream PE nodes to have active redundant multicast flow available during failure of primary flow. Active redundant multicast flow from standby upstream PE allows instant switchover of multicast flow during failure of primary multicast flow.
Faster detection of multicast flow failure is achieved by keeping track of unidirectional multi-point BFD sessions enabled on the provider tunnel. Multi-point BFD sessions must be configured with 10 ms transmit interval on sender (root) PE to achieve sub-50ms fast failover on receiver (leaf) PE.
UMH tunnel-status selection option must be enabled on the receiver PE for upstream fast failover. Primary and standby upstream PE pairs must be configured on the receiver PE to enable active redundant multicast flow to be received from the standby upstream PE.