HP FlexNetwork NJ5000, User Manual

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205
Figure 205 IGMP snooping related ports
The following describes the ports involved in IGMP snooping:
•
Router port
—Layer 3 multicast device-side port. Layer 3 multicast devices include designated
routers and IGMP queriers. In Figure 205 , GigabitEthernet 1/0/1 of Switch A and
GigabitEthernet 1/0/1 of Switch B are router ports. A 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 the Layer 2 interface.
•
Member port
—Multicast receiver-side port. In Figure 205 , GigabitEthernet 1/0/2 and
GigabitEthernet 1/0/3 of Switch A and GigabitEthernet 1/0/2 of Switch B are member ports. A
switch records all its member ports in the IGMP snooping forwarding table.
Unless otherwise specified, router ports and member ports in this document include both dynamic
and static 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.
Aging timers for dynamic ports in IGMP snooping
Timer Description
Message received before
the timer expires Action after the
timer expires
Dynamic
router port
aging timer
When a port receives an
IGMP general query with the
source address other than
0.0.0.0 or 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 with the
source address other than
0.0.0.0 or PIM hello message. 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 or resets an
aging timer for the port. When
the timer expires, the
dynamic member port ages
IGMP membership report.
The switch removes this
port from the IGMP
snooping forwarding
table.