Multimedia Traffic Control with IP Multicast (IGMP)

How IGMP Operates

“X” member on that port. If the port does not receive a join request for that group within the forced-leave interval, the switch then blocks any further group “X” traffic to the port.

Setting Fast-Leave and Forced Fast-Leave from the CLI

In previous software versions, Fast-Leave and Forced Fast-Leave options for a port were set exclusively through the MIB. The following commands now allow a port to be configured for Fast-Leave or Forced Fast-leave operation from the CLI. Note that these commands must be executed in a VLAN context

Syntax: [no] ip igmp fastleave <port-list>

Enables IGMP Fast-Leaves on the specified ports in the VLAN (the default setting). In the Config context, use the VLAN specifier, for example, vlan < vid > ip igmp fastleave <port-list>. The “no” form disables Fast-Leave on the specified ports.

[no] ip igmp forcedfastleave <port-list>

Forces IGMP Fast-Leaves on the specified ports in the VLAN, even if they are cascaded.

To view the IGMP Fast-Leave status of a port use the show running-configor show configuration commands.

Setting Forced Fast-Leave Using the MIB

Fast-Leave and Forced Fast-Leave options for a port can also be set through the switch’s MIB (Management Information Base).

Feature

Default

Settings

Function

Forced Fast­

2

1

(enabled)

Uses the setmib command to enable or disable

Leave state

(disabled)

2

(disabled)

Forced Fast-Leave on individual ports. When

 

 

 

 

enabled on a port, Forced Fast-Leave operates only

if the switch detects multiple end nodes (and at least one IGMP client) on that port.

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