This document describes the procedures and recommendations for VPLS
PEs to facilitate replication of multicast traffic to only certain
ports (behind which there are interested PIM routers and/or IGMP
hosts) via PIM Snooping and PIM Proxy.
With PIM Snooping, PEs passively listen to certain PIM control
messages to build control and forwarding states while transparently
flooding those messages. With PIM Proxy, PEs do not flood PIM Join/
Prune messages but only generate their own and send out of certain
ports, based on the control states built from downstream Join/Prune
messages. PIM Proxy is required when PIM Join suppression is enabled
on the CE devices and useful to reduce PIM control traffic in a VPLS
The document also describes PIM Relay, which can be viewed as light-
weight proxy, where all downstream Join/Prune messages are simply
forwarded out of certain ports but not flooded to avoid triggering
PIM Join suppression on CE devices.