CLI: Configuring and displaying IGMP

Viewing the Current IGMP Configuration. The show ip igmp config command lists the IGMP configuration for all VLANs configured on the switch or for a specific VLAN.

Syntax: show ip igmp config

IGMP configuration for all VLANs on the switch.

show ip igmp < vid > config

IGMP configuration for a specific VLAN on the switch, including per-port data.

(For IGMP operating status, see the appendix on monitoring and analyzing switch operation in the management and configuration guide.)

For example, given the following VLAN and IGMP configurations on the switch:

VLAN ID	VLAN Name	IGMP Enabled	Forward with High Priority	Querier
1	DEFAULT_VLAN	Yes	No	No
22	VLAN-2	Yes	Yes	Yes
33	VLAN-3	No	No	No

The following examples display the data for show ip igmp config, statistics, and group commands:

IGMP configuration for all VLANs on a switch

Switch> show ip igmp config
 IGMP Service
  VLAN ID    VLAN NAME    IGMP Enabled Forward with High Priority Querier 
  ---------- ------------ ------------ -------------------------- -------
  1          DEFAULT_VLAN Yes          No                         No
  22         VLAN-2       Yes          Yes                        Yes
  33         VLAN-3       No           No                         No

Displaying igmp high level statistics for all VLANs on a switch

Syntax:show ip igmp statistics

switch(config)# show ip igmp statistics
IGMP Service Statistic
  Total VLAN's with IGMP enabled:    33
  Current count of multicast groups joined:  21
IGMP Service Statistics
  VLAN ID VLAN Name        Total  Filtered Standard Static
  ------- ---------------- ------ -------- -------- -------
  1       DEFAULT_VLAN     52     50       0        2
  300     Office Client    80     75       5        0
  300     Data Center      1100   1000     99       1

Displaying igmp group address information

Syntax: show ip igmp groups

switch(config)# show ip igmp groups
IGMP Group Address Information
VLAN ID Group Address Expires         UpTime        Last Reporter  | Type
------- ------------- --------------- ------------- -------------- + -----
2       226.0.6.7     0h 2m 58s       1h 13m 4s     192.168.0.2    | Filter
2       226.0.6.8     0h 2m 58s       1h 13m 4s     192.168.0.2    | Standard
2       226.0.6.9     0h 2m 58s       1h 13m 4s     192.168.0.2    | Static

Displaying the IGMP configuration for a specific VLAN

The following show ip igmp command example shows the VLAN ID (vid) designation and the IGMP per-port configuration:

Displaying the IGMP configuration for a specific VLAN

Enabling or disabling IGMP on a VLAN. You can enable IGMP on a VLAN with the last-saved or default IGMP configuration (whichever was most recently set) or you can disable IGMP on a selected VLAN.


	NOTE: The `ip igmp` command must be executed in a VLAN context.

Syntax:[no] ip igmp

Examples of enabling and disabling IGMP on the default VLAN (VID = 1):

Command syntax	Task
`Switch(config)# vlan 1 ip igmp`	Enables IGMP on VLAN 1.
`Switch(vlan-1)# ip igmp`	Disables IGMP on VLAN 1.
`Switch(config)# no vlan 1 ip igmp`	Disables IGMP on VLAN 1.


	NOTE: If you disable IGMP on a VLAN and then later re-enable IGMP on that VLAN, the switch restores the last-saved IGMP configuration for that VLAN. For more information on switch memory operation, see the chapter on switch memory and configuration in the basic operation guide.

You can also combine the ip igmp command with other IGMP-related commands, as described in the following sections.

Configuring Per-Port IGMP Packet Control.

Command syntax	Task
`vlan < vid > ip igmp [ auto <port-list> \| blocked <port-list> \| forward <port-list> ]`	Use this command in the VLAN context to specify how each port should handle IGMP traffic.
`vlan < vid > ip igmp`	Enables IGMP on the specified VLAN. In a VLAN context, use only ip igmp without the VLAN specifier.
`vlan < vid > ip igmp auto <port-list>`(default)	Filter multicast traffic on the specified ports. Forward IGMP traffic to hosts on the ports that belong to the multicast group for which the traffic is intended. (Also forward any multicast traffic through any of these ports that is connected to a multicast router.) This is the default IGMP port configuration.
`vlan < vid > ip igmpblocked <port-list>`	Drop all multicast traffic received from devices on the specified ports and prevent any outgoing multicast traffic from moving through these ports.
`vlan < vid > ip igmp forward < port-list >`	Forward all multicast traffic through the specified port.

For example, to configure IGMP as follows for VLAN 1 on ports 1 - 6:

Ports 1 - 2: Auto
Ports 3 - 4: Forward
Ports 5 - 6: Block

Depending on privilege level, use the following commands to configure IGMP on VLAN 1:

Switch(config)# vlan 1 
switch(vlan-1)# ip igmp auto 1,2 
switch(vlan-1)# ip igmp forward 3,4 
switch(vlan-1)# ip igmp blocked 5,6

After executing the above commands, use the following command to display the VLAN and per-port configuration.

Configuring the querier function

The ip igmp querier command lets you disable or re-enable the ability for the switch to become querier on the specified VLAN. The default querier capability is “enabled”.

Syntax: [no] vlan <vid> ip igmp querier

For example, the following no vlan 1 command disables the querier function on VLAN 1.

Switch(config)# no vlan 1 ip igmp querier

The following show command displays results of the previous querier command.

Switch> show ip igmp config

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CLI: Configuring and displaying IGMP

​Configuring the querier function

Configuring the querier function