Product and Software: This article applies to all Aruba controllers.
IGMP snooping is a method by which controller can "listen in" on IGMP conversations between hosts and routers. When the controller hears a group join message from a host, it notes the VLAN interface it heard the message on, and adds that VLAN interface to the group. Similarly, when the controller hears a group leave message or a response timer expires, the controller removes that host's switch interface from the group.
The multicast is still confined to each VLAN, but instead of being flooded, it is intelligently forwarded to ports in the join list.
Logically, IGMP does not need an IP address to forward the traffic. However for pre 6.1 code, an IP interface must be configured on the VLAN if IGMP snooping is enabled. This BUG 44433 has been fixed and integrated to the 6.1 code onwards.
NOTE: IGMP proxy does need an IP address to send out the traffic.