Configuration Guide User guide

FastIron Configuration Guide 1471
53-1002494-02
IGMP snooping configuration
To specify a list of ports, enter each port as ethernet <port> followed by a space. For example,
ethernet 1/24 ethernet 6/24 ethernet 8/17
To specify a range of ports, enter the first port in the range as ethernet <port> followed by the last
port in the range. For example, ethernet 1/1 to 1/8.
You can combine lists and ranges in the same command. For example: enable ethernet 1/1 to 1/8
ethernet 1/24 ethernet 6/24 ethernet 8/17.
Disabling IGMP snooping on a VLAN
When IGMP snooping is enabled globally, you can still disable it for a specific VLAN. For example,
the following commands cause IGMP snooping to be disabled for VLAN 20. This setting overrides
the global setting.
Brocade(config)# vlan 20
Brocade(config-vlan-20)# multicast disable-multicast-snoop
Syntax: [no] multicast disable-multicast-snoop
Disabling transmission and receipt of IGMP packets
on a port
When a VLAN is snooping-enabled, all IGMP packets are trapped to the CPU without hardware
VLAN flooding. The CPU can block IGMP packets to and from a multicast-disabled port, and does
not add it to the output interfaces of hardware resources. This prevents the disabled port from
receiving multicast traffic. However, if static groups to the entire VLAN are defined, the traffic from
these groups is VLAN flooded, including to disabled ports. Traffic from disabled ports cannot be
blocked in hardware, and is switched in the same way as traffic from enabled ports.
This command has no effect on a VLAN that is not snooping-enabled because all multicast traffic is
VLAN flooded.
To disable transmission and receipt of IGMP packets on a port, enter the following commands.
Brocade(config)# interface ethernet 3
Brocade(config-if-e1000-3)# ip-multicast-disable
The above commands disable IGMP snooping on port 1/5 but does not affect the state of IGMP on
other ports.
Syntax: [no] ip-multicast-disable
Modifying the age interval for group membership entries
When the device receives a group membership report, it makes an entry for that group in the IGMP
group table. The age interval specifies how long the entry can remain in the table before the device
receives another group membership report. When multiple devices connect together, all devices
must be configured for the same age interval, which must be at least twice the length of the query
interval, so that missing one report won't stop traffic. Non-querier age intervals must be the same
as the age interval of the querier.
To modify the age interval, enter the following command.
Brocade(config)# ip multicast age-interval 280