This switch uses IGMP (Internet Group Management Protocol) to query for any
attached hosts that want to receive a specific multicast service. It identifies
the ports containing hosts requesting a service and sends data out to those
ports only. It then propagates the service request up to any neighboring multicast
switch/router to ensure that it will continue to receive the multicast service.
Use this command to statically configure a multicast router port. Use the no
form to remove the configuration.
Command Syntax
ip igmp snooping vlanvlan-idmrouterinterface no ip igmp snooping vlanvlan-idmrouterinterface
vlan-id - VLAN ID (1-4094)
interface
ethernetunit/port
unit - This is device 1.
port - Port number.
port-channelchannel-id (Range: 1-6)
Default Setting
No static multicast router ports are configured.
Command Mode
Global Configuration
Command Usage
Depending on your network connections, IGMP snooping may not always be able
to locate the IGMP querier. Therefore, if the IGMP querier is a known multicast
router/switch connected over the network to an interface (port or trunk) on
your switch, you can manually configure that interface to join all the current
multicast groups.
Example
The following shows how to configure port 11 as a multicast router port within
VLAN 1:
Use this command to configure the query count. Use the no form to restore the default.
Command Syntax
ip igmp snooping query-countcount no ip igmp snooping query-count
count - The maximum number of queries issued for which there has
been no response before the switch takes action to solicit reports. (Range:
2-10)
Default Setting
2 times
Command Mode
Global Configuration
Command Usage
The query count defines how long the querier waits for a response from a
multicast client before taking action. If a querier has sent a number of queries
defined by this command, but a client has not responded, a countdown timer
is started using the time defined by ip igmp snooping query-max- response-time.
If the countdown finishes, and the client still has not responded, then that
client is considered to have left the multicast group.
Example
The following shows how to configure the query count to 10:
Use this command to configure the snooping report delay. Use the no
form of this command to restore the default.
Command Syntax
ip igmp snooping query-max-response-timeseconds no ip igmp snooping query-max-response-time
seconds - The report delay advertised in IGMP queries. (Range:
5-30)
Default Setting
10 seconds
Command Mode
Global Configuration
Command Usage
The switch must be using IGMPv2 for this command to take effect.
This command defines the time after a query, during which a response is
expected from a multicast client. If a querier has sent a number of queries
defined by the ip igmp snooping query-count, but a client has not responded,
a countdown timer is started using an initial value set by this command. If
the countdown finishes, and the client still has not responded, then that
client is considered to have left the multicast group.
Example
The following shows how to configure the maximum response time to 20 seconds:
Use this command to configure the snooping query-timeout. Use the no
form of this command to restore the default.
Command Syntax
ip igmp snooping query-time-out seconds no ip igmp snooping query-time-out
seconds - The time the switch waits after the previous querier
stops before it considers the router port (i.e., the interface which had
been receiving query packets) to have expired. (Range: 300-500)
Default Setting
300 seconds
Command Mode
Global Configuration
Command Usage
The switch must be using IGMPv2 for this command to take effect.
Example
The following shows how to configure the default timeout to 300 seconds:
Use this command to configure the IGMP snooping version. Use the no
form to restore the default.
Command Syntax
ip igmp snooping version {1 | 2} no ip igmp snooping version
1 - IGMP Version 1
2 - IGMP Version 2
Default Setting
IGMP Version 2
Command Mode
Global Configuration
Command Usage
All systems on the subnet must support the same version. If there are legacy
devices in your network that only support Version 1, you will also have to
configure this switch to use Version 1.
Some commands are only enabled for IGMPv2, including ip igmp query-max-response-time
and ip igmp query-timeout.
Example
The following configures the switch to use IGMP Version 1:
Console(config)#ip igmp snooping
version 1 Console(config)#
Use this command to display information on statically configured and dynamically
learned multicast router ports.
Command Syntax
show ip igmp snooping mrouter [vlanvlan-id]
vlan-id - VLAN ID (Range: 1-4094)
Default Setting
Displays multicast router ports for all configured VLANs.
Command Mode
Privileged Exec
Command Usage
Multicast router port types displayed include Static or Dynamic.
Example
The following shows the ports in VLAN 1 which are attached to multicast routers:
Console#show ip igmp snooping
mrouter vlan 1
VLAN M'cast Router Port Type
---- ------------------ -------
1 Eth
1/11 Static
2 Eth
1/12 Dynamic
Console#
