IGMP Proxy

IGMP Proxy provides a means for routers to receive any or all multicast traffic from an upstream device if the router is not able to run PIM and runs only IGMP. IGMP Proxy supports IGMP v1, v2, and v3.

IGMP Proxy enables the router to issue IGMP host messages on behalf of hosts that the router discovered through standard PIM interfaces. The router acts as a proxy for its hosts and performs the host portion of the IGMP task on the upstream interface as follows:

• When queried, the router sends group membership reports for the groups learned.
• When one of its hosts joins a multicast address group to which none of its other hosts belong, the router sends unsolicited membership reports to that group.
• When the last of its hosts in a particular multicast group leaves the group, the router sends an unsolicited leave group membership report to group (multicast IP address 224.0.0.2).