A multicast device starts a timer for each (S, G) entry. If the multicast device does not receive any multicast packets from a multicast source within the set lifetime of the multicast source, it considers that the (S, G) entry becomes invalid and the multicast source stops sending multicast data to the multicast group.
pim [ vpn-instance vpn-instance-name ]
source-lifetime interval
If a FW does not receive any (S, G) packet in the lifetime of the source, the FW considers that the source stops sending multicast data to G and the (S, G) entry becomes invalid.
When State-Refresh is enabled, the lifetime of the multicast source is prolonged to about the value of interval.