Multicast Listener Discovery (MLD) is a component of the Internet Protocol Version 6 (IPv6) suite. MLD is used by IPv6 routers for discovering multicast listeners on a directly attached link, much like Internet Group Management Protocol (IGMP) is used in IPv4. Instead of being implemented as a separate protocol, the protocol is embedded in ICMPv6. MLDv1 is similar to IGMPv2 and MLDv2 similar to IGMPv3..

Protocol

The following ICMPv6 message types are used:

ICMPv6 message type values Message Type value Multicast Listener Query 130 MLDv1 Multicast Listener Report 131 MLDv2 Multicast Listener Report 143 Multicast Listener Done 132

All MLDv1/MLDv2 messages have a link-local IPv6 Source Address (fe80::/10). MLDv2 Reports may be sent from the unspecified address (::/128) if no valid link-local IPv6 source address is present.

MLDv2 Multicast Listener Reports are sent to ff02::16, to which all MLDv2-capable multicast routers listen.

Support

Several operating systems support MLDv2: