Nokia routers are capable of interoperating with routers and hosts running IGMPv1, IGMPv2, and/or IGMPv3. RFC 5186, Internet Group Management Protocol Version 3 (IGMPv3)/Multicast Listener Discovery Version 2 (MLDv2) and Multicast Routing Protocol Interaction explores the interoperability issues and how they affect the routing protocols.
IGMPv3 specifies that if a router receives an earlier version query message on an interface, it must immediately switch to a mode that is compatible with the earlier version. Because the previous versions of IGMP are not source-aware, should this occur and the interface switches to version 1 or 2 compatibility mode, any previously learned group memberships with specific sources (learned via the IGMPv3-specific INCLUDE or EXCLUDE mechanisms) must be converted to non-source specific group memberships. The routing protocol then treats the query as if there is no EXCLUDE definition present.