H3C Technologies H3C S7500E Series Switches - Manual (Page 260)

9-4
Aging timers for dynamic ports in MLD Snooping
Table 9-1 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 sets a timer
initialized to the dynamic
router port aging time.
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
an IPv6 multicast group, the
switch sets a timer for the
port, which is initialized to the
dynamic member port aging
time.
MLD report message.
The switch removes
this port from the MLD
snooping forwarding
table.
The port aging mechanism of MLD snooping works only for dynamic ports; a static port will
never age out.
How MLD Snooping Works
A switch running MLD snooping performs different actions when it receives different MLD
messages, as follows:
The description about adding or deleting a port in this section is only for a dynamic port. Static
ports can be added or deleted only through the corresponding configurations. For details, see
Configuring Static Ports .
General queries
The MLD querier periodically sends MLD general queries to all hosts and routers (FF02::1) on
the local subnet to find out whether IPv6 multicast group members exist on the subnet.
Upon receiving an MLD general query, the switch forwards it through all ports in the VLAN
except the port on which it received the MLD query and performs the following:
z If the port on which it the switch received the MLD query is a dynamic router port in its
router port list, the switch resets the aging timer for this dynamic router port.