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    immediate-leave (IGMP Snooping)

    Syntax

    immediate-leave;

    Hierarchy Level

    [edit protocols igmp-snooping vlan (all | vlan-name)]

    Release Information

    Statement introduced in Junos OS Release 9.1 for EX Series switches.

    Description

    Configure IGMP snooping immediate leave for the specified VLAN. When you configure immediate leave, host tracking is enabled, which allows the switch to track the hosts that send membership reports. The switch can then determine when the last host on an interface leaves the multicast group and immediately stop forwarding multicast traffic to the interface.

    Configuring immediate leave reduces the amount of time it takes for the switch to stop sending multicast traffic to an interface when the last host leaves the group. When immediate leave is disabled, the switch no longer tracks hosts. Instead, whenever it receives a leave report from a host, it sends out a group-specific query to all hosts. If it does not receive any membership reports on the interface in response to the group-specific query within a set interval, it stops forwarding multicast traffic to the interface.

    Note: Immediate leave is supported for both IGMP version 2 (IGMPv2) and IGMPv3. However, with IGMPv2, we recommend that you configure immediate leave only when there is only one IGMP host on an interface. In IGMPv2, only one host on a interface sends a membership report in response to a general query—any other interested hosts suppress their reports. Report suppression avoids a flood of reports for the same group, but it also interferes with host tracking because the switch knows only about one interested host on the interface at any given time.

    Default

    The immediate-leave feature is disabled.

    Required Privilege Level

    routing—To view this statement in the configuration.
    routing-control—To add this statement to the configuration.

    Modified: 2013-02-20