Additional IGMP Features
FastLeave
IGMP Filtering
Configuring the Range
520
G8264 Application Guide for ENOS 8.4
The following topics are discussed in this section:
"FastLeave" on page 520
"IGMP Filtering" on page 520
"Static Multicast Router" on page 521
In normal IGMP operation, when the switch receives an IGMPv2 Leave message, it
sends a Group‐Specific Query to determine if any other devices in the same group
(and on the same port) are still interested in the specified multicast group traffic.
The switch removes the affiliated port from that particular group, if the switch
does not receive an IGMP Membership Report within the query‐response‐interval.
With FastLeave enabled on the VLAN, a port can be removed immediately from
the port list of the group entry when the IGMP Leave message is received.
Note: Only IGMPv2 supports FastLeave. Enable FastLeave on ports that have only
one host connected. If more than one host is connected to a port, you may lose
some hosts unexpectedly.
Use the following command to enable FastLeave.
#
RS G8264(config)
ip igmp fastleave <VLAN number>
With IGMP filtering, you can allow or deny certain IGMP groups to be learned on
a port.
If access to a multicast group is denied, IGMP Membership Reports from the port are
dropped, and the port is not allowed to receive IPv4 multicast traffic from that
group. If access to the multicast group is allowed, Membership Reports from the
port are forwarded for normal processing.
To configure IGMP filtering, you must globally enable IGMP filtering, define an
IGMP filter, assign the filter to a port, and enable IGMP filtering on the port. To
define an IGMP filter, you must configure a range of IPv4 multicast groups, choose
whether the filter will allow or deny multicast traffic for groups within the range,
and enable the filter.
Each IGMP filter allows you to set a start and end point that defines the range of
IPv4 addresses upon which the filter takes action. Each IPv4 address in the range
must be between 224.0.0.0 and 239.255.255.255.