Introduction To Mld - Edge-Core ES3628EA User Manual

17.3 MLD

17.3.1 Introduction to MLD

MLD (Multicast Listener Discovery) is the multicast group member (receiver)
discovery protocol serving IPv6 multicast. It is similar to IGMP Protocol in IPv4 multicast
application. Correspondingly, MLD Protocol version1 is similar to IGMP Protocol version2,
and MLD Protocol version2 is similar to IGMP Protocol version3. Current firmware only
supports MLDv1.
The IPv6 multicast hosts can join or leave from multicast group at any location, any
time, regardless of the total number of group members. It is unnecessary and impossible
for multicast switch to store the relationship among all host members. Multicast switch
simply finds out via MLD protocol if there are receivers of certain multicast group on the
network segment connected to each port. The only thing host need to do is to keep the
record of which multicast groups it joined.
MLD is unsymmetrical between host and switch: the host needs to respond the MLD
query message of multicast switch with membership report message; the switch
periodically sends membership query message and determines if there is host joining a
specific group in its subnetworks according to the response message received, and after
it receives the report of a host quitting from the group, it sends out the query for the group
to confirm if there is no member left in it.
There are three types of protocol messages of MLD Protocol, that is, Query, Report
and Done (which is corresponding to Leave of IGMPv2). Like IGMPV2, the Query
messages include General Query and Specific Group Query. General Query uses the
multicast address FF02::1 of hosts as destination address, the group address is 0; and
Specific Group Query use its group address as destination address. The multicast
addresses of MLD use 130, 131 and 132 as data types denoting the three kinds of
messages mentioned above. Other logic is basically same as IGMPv2.
17.3.2 MLD Configuration Task List
1、 Start MLD (Required)
2、 Configure MLD auxiliary parameters (Required)
（1）Configure MLD group parameters
1）Configure MLD group filter conditions
（2）Configure MLD query parameters
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