Lantronix
SM12XPA Web User Guide
33848 Rev. A
Page
155
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473
MLD Snooping
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. The protocol is embedded in ICMPv6 instead of using a separate
protocol. MLDv1 is similar to IGMPv2 and MLDv2 is similar to IGMPv3. The protocol is described in IETF
which has been updated by
A network node that acts as a source of IPv6 multicast traffic is only an indirect participant in MLD snooping;
it just provides multicast traffic, and MLD doesn’t interact with it. (Note, however, that in an application like
desktop conferencing a network node may act as both a source and an MLD host; but MLD interacts with that
node only in its role as an MLD host.)
A source node creates multicast traffic by sending packets to a multicast address. In IPv6, addresses with the
first eight bits set (that is, “FF” as the first two characters of the address) are multicast addresses, and any node
that listens to such an address will receive the traffic sent to that address. Application software running on the
source and destination systems cooperates to determine what multicast address to use. (Note that this is a
function of the application software, not of MLD.)
When MLD snooping is enabled on a VLAN, the switch acts to minimize unnecessary multicast traffic. If the
switch receives multicast traffic destined for a given multicast address, it forwards that traffic only to ports on
the VLAN that have MLD hosts for that address. It drops that traffic for ports on the VLAN that have no MLD
hosts.
Figure 9-2: MLD snooping enabled
Web Interface
To configure MLD Snooping in the web UI:
1.
Click Multicast, MLD Snooping, and Basic Configuration.
2.
Set the Global Configuration parameters.
3.
Set the Port Related Configuration parameters.
4.
Click the Apply button to save the settings.
5.
To cancel the settings, click the Reset button. It will revert to previously saved values.