Use the ip igmp snooping global configuration command to enable Internet Group Management Protocol (IGMP) snooping. To disable IGMP snooping, use the no form of this command.
Syntax
ip igmp snooping
no ip igmp snooping
Default Configuration
IGMP snooping is disabled.
Command Mode
Global Configuration Mode
User Guidelines
None
Example
The following example enables IGMP snooping.
Console (config)# ip igmp snooping
ip igmp snooping (Interface)
Use the ip igmp snooping interface configuration command to enable Internet Group Management Protocol (IGMP) snooping on a specific VLAN. To disable IGMP snooping on a VLAN interface, use the no form of this command.
Syntax
ip igmp snooping
no ip igmp snooping
Default Configuration
IGMP snooping is disabled on all VLANs in the set context.
Command Mode
Interface Configuration (VLAN) Mode
User Guidelines
IGMP snooping can only be enabled on static VLANs.
Example
The following example enables IGMP snooping on VLAN 2.
Console (config)# interface vlan 2
Console (config-if)# ip igmp snooping
ip igmp snooping mrouter
The ip igmp snooping mrouter interface configuration command enables automatic learning of multicast router ports in the context of a specific VLAN. To remove automatic learning of multicast router ports, use the no form of this command.
Syntax
ip igmp snooping mrouter learn-pim-dvmrp
no ip igmp snooping mrouter learn-pim-dvmrp
Default Configuration
Automatic learning of mrouter ports is enabled.
Command Mode
Interface Configuration (VLAN) Mode
User Guidelines
Auto-learning is performed by either IGMP queries or by listening to PIM (Protocol Independent Multicast) and DVMRP (Distance Vector Multicast Routing Protocol) transmissions, even though these protocols are not participated in/supported on this device (transmission is simply eavesdropped on). The senders are multicast routers, so that ports that have mrouters connected to them may be identified by simply listening.
The following example enables automatic learning of multicast router ports on VLANs.
Console (config) # interface vlan 2
Console (config-if)# ip igmp snooping mrouter learn-pim-dvmrp
ip igmp snooping host-time-out
Use the ip igmp snooping host-time-out interface configuration command to configure the host-time-out. If an IGMP Report for a multicast group was not received for a host-time-out period, from a specific port, this port is deleted from the member list of that multicast group. To reset to default host-time-out, use the no form of this command.
Syntax
ip igmp snooping host-time-out time-out
no ip igmp snooping host-time-out
time-out—host timeout in seconds (Range: 1-2147483647).
Default Configuration
The default host-time-out is 150 seconds.
Command Mode
Interface Configuration (VLAN) Mode
User Guidelines
The timeout should be at least 3 times greater then the query period time of the IGMP device.
Example
The following example configures the host timeout.
Console (config)# interface vlan 2
Console (config-if)# ip igmp snooping host-time-out 300
ip igmp snooping mrouter-time-out
Use the ip igmp snooping mrouter-time-out interface configuration command to configure the mrouter-time-out. The mrouter-time-out is used for setting the aging-out time after multicast router ports are automatically learned. To configure the default mrouter-time-out, use the no form of this command.
Syntax
ip igmp snooping mrouter-time-outtime-out
no ip igmp snooping mrouter-time-out
time-out—mrouter timeout in seconds (Range: 1-2147483647)
Default Configuration
The default value is 300 seconds.
Command Mode
Interface Configuration (VLAN) Mode
User Guidelines
There are no user guidelines for this command.
Example
The following example configures the mrouter timeout.
Console (config)# interface vlan 2
Console (config-if)# ip igmp snooping mrouter-time-out 300
ip igmp snooping leave-time-out
Use the ip igmp snooping leave-time-out command to configure the leave-time-out. If an IGMP report for a multicast group is not received within the leave-time-out period after an IGMP leave message was received from a specific port, the current port is deleted from the member list of that multicast group. To configure the default leave-time-out, use the no form of this command.
Syntax
ip igmp snooping leave-time-out {time-out | immediate-leave}
no ip igmp snooping leave-time-out
time-out—leave-time-out in seconds (Range: 0-2147483647).
immediate-leave—Specifies that the port should be immediately removed from the members list after receiving IGMP Leave message.
Default Configuration
The default leave-time-out configuration is 10 seconds.
Command Mode
Interface Configuration (VLAN) Mode
User Guidelines
The leave timeout should be set to greater than the maximum time that a host is allowed to respond to an IGMP Query.
Use immediate leave only where there is only one host connected to a port.
The following example configures the host leave-time-out.
Console (config)# interface vlan 2
Console (config-if)# ip igmp snooping leave-time-out 60
show ip igmp snooping mrouter
Use the show ip igmp snooping mrouter privileged EXEC command to display information on dynamically learned multicast router interfaces.
Syntax
show ip igmp snooping mrouter [interface vlan-id]
vlan_id—VLAN ID value.
Default Configuration
This command has no default configuration.
Command Mode
Privileged EXEC Mode
User Guidelines
There are no user guidelines for this command.
Example
The following example displays IGMP snooping mrouter information on VLAN 1000.
Console # show ip igmp snooping mrouter interface 200
VLAN Ports
------- -----------------------------------------
200 1/e1, 2/e1
show ip igmp snooping interface
Use the show ip igmp snooping interface privileged EXEC command to display IGMP snooping configuration.
Syntax
show ip igmp snooping interface vlan-id
vlan_id—VLAN ID value.
Default Configuration
This command has no default configuration.
Command Mode
Privileged EXEC Mode
User Guidelines
There are no user guidelines for this command.
Example
The following example displays IGMP snooping information on VLAN 1000.
Console # show ip igmp snooping interface 1000
IGMP Snooping is globally enabled
IGMP Snooping is enabled on VLAN 1000
IGMP host timeout is 300 sec
IGMP Immediate leave is disabled. IGMP leave timeout is 10 sec
IGMP mrouter timeout is 300 sec
Automatic learning of multicast router ports is enabled
show ip igmp snooping groups
Use the show ip igmp snooping groups command to display the multicast groups learned by IGMP snooping.
Syntax
show ip igmp snooping groups [vlan vlan-id] [address ip-multicast-address]
vlan_id—VLAN ID value
ip-multicast-address—IP multicast address
Default Configuration
This command has no default configuration.
Command Mode
Privileged EXEC Mode
User Guidelines
To see the full multicast address table (including static addresses) use the show bridge address-table command.
Example
The following example displays IGMP snooping information on VLAN 1000.
