The IGMPLevel parameter sets the level that the system supports IP multicast and participates in the Internet Group Management ...

The IGMPLevel parameter sets the level that the system supports IP multicast and participates in the Internet Group Management Protocol. At level 0, the system provides no multicast support. At level 1, the system may only send IP multicast packets. At level 2, the system may send IP multicast packets and fully participate in IGMP to receive multicast packets.