Dell BigIron RX Series, Configuration Manual

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1068 BigIron RX Series Configuration Guide
53-1002253-01
Enabling IP multicast traffic reduction
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When you enable IP multicast for a specific VLAN instance, IGMP snooping is enabled. The device
uses IGMP to maintain a table of the Group Membership reports received by the device for the
specified VLAN instance. You can use active or passive IGMP mode. There is no default mode.The
IGMP modes are as follows:
•
Active – When active IGMP mode is enabled, the router actively sends out IGMP queries to
identify IP multicast groups within the VLAN instance and makes entries in the IGMP table
based on the Group Membership reports received from the network.
•
Passive – When passive IGMP mode is enabled, the router listens for IGMP Group Membership
reports on the VLAN instance specified but does not send IGMP queries. The passive mode is
called “IGMP snooping”. Use this mode when another device in the VLAN instance is actively
sending queries.
Modifying the query interval
If IP Multicast Traffic Reduction is set to active mode, you can modify the query interval, which
specifies how often a device enabled for active IP Multicast Traffic Reduction sends Group
Membership queries.
NOTE
The query interval applies only to the active mode of IP Multicast Traffic reduction.
To modify the query interval, enter a command such as the following.
BigIron RX(config)# ip multicast query-interval 120
Syntax: [no] ip multicast query-interval < interval >
The < interval > parameter specifies the interval between queries. You can specify a value from 10
– 600 seconds. The default is 125 seconds.
Modifying the age interval
When the device receives a Group Membership report, the device makes an entry in the IGMP
group table for the group in the report. The age interval specifies how long the entry can remain in
the table without the device receiving another Group Membership report.
To modify the age interval, enter a command such as the following.
BigIron RX(config)# ip multicast age-interval 280
Syntax: [no] ip multicast age-interval < interval >
The < interval > parameter specifies the interval between queries. You can specify a value from 10
– 1220 seconds. The default is 260 seconds.
Filtering multicast groups
By default, the BigIron RX forwards multicast traffic for all valid multicast groups. You can configure
a device to filter out all multicast traffic for groups other than the ones for which the device has
received Group Membership reports.