Multicast support provides the VPN Gateway the ability to collect IGMP group join/prune requests on the local VLAN. These IGMP requests are then converted to PIM-Sparse Mode requests and forwarded through the AT&T ANIRA IPSec tunnel to a statically defined RP (Rendezvous Point). PIM Shortest Path Tree (SPT) will be negotiated when the first multicast data packet is received from a source different from the RP. Only one multicast enabled IPSec tunnel is supported.