Multicast Listener Discovery | 607Leaving a Multicast GroupA receiver that is no longer interested in traffic for a particular group should leave the group by sending aDone message to the link-scope all-routers multicast address, FF02::02.When a Querier receives a Done message, it sends a Multicast-Address-Specific Query addressed to therelevant multicast group. Hosts still interested in receiving traffic for that group (according to thesuppression mechanism) so that the group table entry is maintained. If no reports are received in responseto the query, the group membership entry is cleared and the router stops forwarding traffic for that group.MLD version 2MLD version 2 (MLDv2) adds source-filtering capability. A node can report interest in multicast trafficonly from specific source addresses or from all sources except for specific source addresses. MLDv2 isbackwards compatible with MLD version 1.There are two types of MLDv2 messages• Multicast Listener Query — a message sent by the Querier to discover multicast listeners(Figure 27-2).• General Query — a query to which all listeners should respond.• Multicast-Address-Specific Query — a query to which listeners for the specified group shouldrespond to affirm their membership.• Multicast-Address-and-Source-Specific Query — a query to determine if there are any listenersinterested in a group and source pair.• Version 2 Multicast Listener Report — a response to a query indicating listening state or statechanges (Figure 27-3).Figure 27-2. MLDv2 Multicast Listener QueryVersion(6)Traffic Class Flow Label Payload Length Next Header(0)Hop Limit(1) ICMPv6 PacketPreamble Start FrameDelimiterDestination MAC Source MAC Ethernet Type IPv6 Packet PaddingMLD 002Type Code(0)Multicast AddressChecksumCode: 130: Multicast Listener Query131: Multicast Listener Report132: Multicast Listener DoneFCSNext Header(58)Header ExtensionLength(0)Options(Router Alert)Max. ResponseDelayReserved Reserved S Querier RobustnessVariableQuerier's QueryInterval CodeN Source Addresses
