Multicast Listener Discovery
Protocol for discovering IPv6 multicast listeners
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..
01Protocol
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.
02Support
Several operating systems support MLDv2:
- Windows Vista and later
- FreeBSD since release 8.0
- The Linux kernel since 2.5.68
- macOS
Sources and credits
This article is adapted from the Wikipedia article “Multicast Listener Discovery”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
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