Install guide

22 Software Reference
You can configure the IGMP proxy agent to monitor the reception of IGMP
general query messages on an interface, and to generate a log message and an
SNMP trap if an IGMP general query message is not received on the interface
within a specified time interval.
To enable monitoring on an interface and set the time interval, use the
command:
set ip igmp interface=interface querytimeout={none|0|
1..65535}
To display information about IGMP and the IGMP proxy agent, use the
command:
show ip igmp
IGMP Snooping
IGMP snooping lets switches intelligently forward multicast traffic instead of
flooding all ports in the VLAN. Because IGMP is an IP-based protocol,
multicast group membership for VLAN-aware devices is on a per-VLAN basis.
If at least one port in the VLAN is a member of a multicast group and IGMP
snooping is not enabled, multicast packets are flooded out all ports in the
VLAN.
When IGMP snooping is enabled, the switch listens to IGMP membership
reports, queries, and leave messages to identify which ports are members of
multicast groups. Multicast traffic is then forwarded only to ports that are
members of the multicast group.
IGMP snooping happens automatically at Layer 2 on VLAN interfaces. By
default, the switch forwards traffic from ports with multicast listeners, and
does not act as a simple hub and flood multicast traffic from all ports. IGMP
snooping is independent of the IGMP and Layer 3 configuration, so an IP
interface does not have to be attached to the VLAN, and IGMP does not have to
be enabled or configured.
IGMP snooping is enabled by default. To disable it, use the command:
disable igmpsnooping
Disabling IGMP snooping may be useful when filters are used extensively
because IGMP snooping uses a Layer 3 filter. When IGMP snooping is
disabled, this filter becomes available. See “Hardware Packet Filters” in the
Switching chapter of your Software Reference for information about filters.
Note that multicast packets flood the VLAN when IGMP snooping is disabled.
To enable IGMP snooping, use the command:
enable igmpsnooping
IGMP snooping can be enabled only when a free filter entry is available.
To display information about IGMP snooping, use the command:
show igmpsnooping [vlan={vlan-name|1..4094}]
To display counters for IGMP snooping, use the command:
show igmpsnooping counter [vlan={vlan-name|1..4094}]