H3C Technologies H3C S12500 Series Switches - Manual (Page 30)

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Figure 12 IGMP snooping related ports
Ports involved in IGMP snooping, as shown in Figure 12 , are described as follows:
• Router port—Layer 3 multicast device-side port. Layer 3 multicast devices include DRs and IGMP
queriers. In
Figure 12 , GigabitEthernet 3/0/1 of Device A and GigabitEthernet 3/0/1 of Device B
are router ports. The switch records all its local router ports in its router port list.
Do not confuse the "router port" in IGMP snooping with the "routed interface" commonly known as
the "Layer 3 interface." The router port in IGMP snooping is a Layer 2 interface.
• Member port—Multicast receiver-side port. In Figure 12 , GigabitEthernet 3/0/2 and
GigabitEthernet 3/0/3 of Device A and GigabitEthernet 3/0/2 of Device B are member ports. The
switch records all the member ports on the local device in its IGMP 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 IGMP snooping is enabled, all ports that receive PIM hello messages or IGMP general queries with
the source addresses other than 0.0.0.0 are considered dynamic router ports. For more information about
PIM hello messages, see "Configuring PIM."
Aging timers for dynamic ports in IGMP snooping
Timer Description
Message before
expiration
Action after expiration
Dynamic router port
aging timer
When a port receives an
IGMP general query with
source address other
than 0.0.0.0 or a PIM
hello message, the switch
starts or resets an aging
timer for the port. When
the timer expires, the
dynamic router port ages
out.
IGMP general query
source address other
than 0.0.0.0 or PIM
hello.
The switch removes this
port from its router port
list.