55
Figure 23 MLD snooping related ports
The following describes the ports involved in MLD snooping, as shown in
:
•
Router
port
—Layer 3 multicast device-side port. Layer 3 multicast devices include designated
routers and MLD queriers. In
, GigabitEthernet 1/0/1 of Switch A and GigabitEthernet
1/0/1 of Switch B are the router ports. A Layer 2 device records all its local router ports in a
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 a Layer 2 interface.
•
Member
port
—Multicast receiver-side port. In
, GigabitEthernet 1/0/2 and
GigabitEthernet 1/0/3 of Switch A and GigabitEthernet 1/0/2 of Switch B are member ports. A
Layer 2 device records all its local 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:
When MLD snooping is enabled, all ports that receive IPv6 PIM hello messages or MLD general
queries with a source IP address other than 0::0 are considered dynamic router ports.
Aging timers for dynamic ports in MLD snooping
The following are aging timers for dynamic ports in MLD snooping:
•
Dynamic router port aging timer
—The Layer 2 device starts this timer for a port that receives
an MLD general query with the source address other than 0::0 or an IPv6 PIM hello message. If
the port does not receive either of these messages before the timer expires, the Layer 2 device
removes the port from its router port list.
•
Dynamic member port aging timer
—The Layer 2 device starts this timer for a port that
receives an MLD report. If the port does not receive a report before the timer expires, the Layer
2 device removes the port from the MLD snooping forwarding entries.
NOTE:
In MLD snooping, only dynamic ports age out. Static ports never age out.
Router A
Switch A
Switch B
GE1/0/1
GE1/0/2
GE1/0/3
GE1/0/1
GE1/0/2
Receiver
Receiver
Host A
Host B
Host C
Host D
Source
IPv6 multicast packets
Router port
Member port
