How Igmp Snooping Works - H3C S5810 Series Operation Manual

Whenever mentioned in this document, a router port is a port on the switch that leads the switch to
a Layer 3 multicast device, rather than a port on a router.
Unless otherwise specified, router/member ports mentioned in this document include static and
dynamic ports.
An IGMP-snooping-enabled switch deems that all its ports on which IGMP general queries with the
source IP address other than 0.0.0.0 or PIM hello messages are received are dynamic router ports.
Aging timers for dynamic ports in IGMP Snooping and related messages and actions
Table 1-1 Aging timers for dynamic ports in IGMP Snooping and related messages and actions
Timer
Dynamic router port
aging timer
Dynamic member port
aging timer
The port aging mechanism of IGMP Snooping works only for dynamic ports; a static port will never age
out.

How IGMP Snooping Works

A switch running IGMP Snooping performs different actions when it receives different IGMP 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
Ports.
Description
For each dynamic
router port, the switch
sets a timer initialized
to the dynamic router
port aging time.
When a port
dynamically joins a
multicast group, the
switch sets a timer for
the port, which is
initialized to the
dynamic member port
aging time.
1-3
Message before
expiry
IGMP general query of
which the source
address is not 0.0.0.0
or PIM hello
IGMP membership
report
Action after expiry
The switch removes
this port from its router
port list.
The switch removes
this port from the IGMP
Snooping forwarding
table.
Configuring Static