59
Figure 22
MLD snooping related ports
Ports involved in MLD snooping, as shown in
, are described as follows:
•
Router port
—Layer 3 multicast device-side port. Layer 3 multicast devices include designated
routers (DRs) and MLD querier. In the figure, Ethernet 1/0/1 of Switch A and Ethernet 1/0/1 of
Switch B are router ports. The switch registers all its router ports in its router port list.
Do not confuse the "router port" in MLD snooping with the "routed interface" commonly known as
the "Layer 3 interface." The router port in MLD snooping is the Layer 2 interface.
•
Member port
—Multicast receiver-side port. In the figure, Ethernet 1/0/2 and Ethernet 1/0/3 of
Switch A and Ethernet 1/0/2 of Switch B are member ports. The switch registers all its member
ports in its MLD snooping forwarding table.
Unless otherwise specified, router ports and member ports in this document include both static and
dynamic router ports and member ports.
NOTE:
An MLD snooping-enabled switch deems that the all its ports that receive MLD general queries with the
source address other than 0::0 or that receive IPv6 PIM hello messages are dynamic router ports.
Aging timers for dynamic ports in MLD snooping and related messages and actions
Timer Description
Message before expiry
Action after expiry
Dynamic router
port aging timer
For each dynamic router port,
the switch starts an aging timer.
When the timer expires, the
dynamic router port ages out.
MLD general query of
which the source address
is not 0::0 or IPv6 PIM
hello.
The switch removes this
port from its router port
list.
Dynamic member
port aging timer
When a port dynamically joins
a multicast group, the switch
starts an aging timer for the
port. When the timer expires,
the dynamic member port ages
out.
MLD report message.
The switch removes this
port from the MLD
snooping forwarding
table.
