For PIM proxy configurations, VPLS PE routers perform the following:
snoop hellos and flood hellos in the fast data path
consume join/prune messages from CE routers
generate join/prune messages upstream using the IP address of one of the downstream CE routers
run an upstream PIM state machine to determine whether a join/prune message should be sent upstream
Join/prune suppression is not required to be disabled on CE routers, but it requires all PEs in the VPLS to have PIM proxy enabled. Otherwise, CEs behind the PEs that do not have PIM proxy enabled may not be able to get multicast traffic that they are interested in if they have join/prune suppression enabled.
When PIM proxy is enabled, if a VPLS PE router detects a condition where join/prune suppression is disabled on all CE routers, the PE router puts PIM proxy into a plain PIM snooping state to improve efficiency. A trap is generated to report the scenario to the operator and is logged to the syslog. If the condition changes, for example, join/prune suppression is enabled on a CE router, PIM proxy is placed back into the operational state. Again, a trap is generated to report the condition to the operator and is logged to the syslog.