Three versions of IGMP are specified:
- IGMPv1, defined by RFC 1112, Host Extensions for IP Multicasting
- IGMPv2, defined by RFC 2236, Internet Group Management Protocol, Version 2
- IGMPv3, defined by RFC 3376, Internet Group Management Protocol, Version 3 and updated by RFC 4604, Using Internet Group Management Protocol Version 3 (IGMPv3) and Multicast Listener Discovery Protocol Version 2 (MLDv2) for Source-Specific Multicast
Relative to IGMPv1, IGMPv2 adds the ability for a host to leave a multicast group. Relative to IGMPv2, IGMPv3 adds support for source-specific multicast. For more information on IGMPv3 support for source-specific multicast, refer to Ciena Vyatta Network OS Multicast Routing Configuration Guide.