Configuring IGMP ports

Configure IGMP for each interface to change default multicasting operations.

Note

When you configure the following IGMP parameters on the DvR enabled interface of a DvR Controller, the configuration is automatically pushed to the Leaf nodes within the domain.

ip igmp version
ip igmp query-interval
ip igmp query-max-response
ip igmp robust-value
ip igmp last-member-query-interval
ip igmp compatibility-mode

For more information on DvR, see .

Procedure

Enter GigabitEthernet Interface Configuration mode:

enable

configure terminal

interface GigabitEthernet {slot/port[/sub-port][-slot/port[/sub-port]][,...]}

Note

If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.
Enable IGMP v2-v3 compatibility mode:

ip igmp compatibility-mode
Configure the system to downgrade the version of IGMP:

ip igmp dynamic-downgrade-version
Configure message intervals and response times:

ip igmp last-member-query-interval <0–255> [query-interval <1–65535>] [query-max-response <0–255>]
Configure expected packet loss and IGMP version:

ip igmp robust-value <2–255> [version <1–3>]
Configure IGMP for a specific port:

ip igmp port {slot/port[/sub-port][-slot/port[/sub-port]][,...]}
Enable router alert:

ip igmp router-alert

Example

Configure message intervals and response times:

Switch(config-if)#ip igmp last-member-query-interval 30 query-interval 60 query-max-response 90

Configure expected packet loss and IGMP version:

Switch(config-if)#ip igmp robust-value 2 version 3

Configure IGMP for a specific port:

Switch(config-if)#ip igmp port 1/4

Enable router alert:

Switch(config-if)#ip igmp router-alert

Variable definitions

Use the definitions in the following table to use the ip igmp command.


Variable	Value
access-list `WORD<1–64>` {A.B.C.D/X} <eny-tx\|deny-rx\|deny-both\|allow-only-tx\|allow-only-rx\|allow-only-both>	Specifies the name of the access list from 1–64 characters. Creates an access control group entry for a specific IGMP interface. Specify the IP address of the host and the subnet mask used to determine the host or hosts covered by this configuration. You can use the host subnet mask to restrict access to a portion of the network for the host. Indicates the action for the specified IGMP interface. For example, if you specify deny-both, the interface denies both transmitted and received traffic
compatibility-mode	Activates v2-v3 compatibility mode. The default value is disabled, which means IGMPv3 is not compatible with IGMPv2. To use the default configuration, use the default option in the command: `default ip igmp compatibility-mode` , or use the no option to disable compatibility mode: `no ip igmp compatibility-mode`
dynamic-downgrade-version	Configures if the system downgrades the version of IGMP to handle older query messages. If the system downgrades, the host with IGMPv3 only capability does not work. If you do not configure the system to downgrade the version of IGMP, the system logs a warning. The system downgrades to the oldest version of IGMP on the network by default. To use the default configuration, use the default option in the command: `default ip igmp dynamic-downgrade-version` or use the no option to disable downgrade: `no ip igmp dynamic-downgrade-version`
igmpv3-explicit-host-tracking	Enables explicit host tracking on IGMPv3. The default state is disabled.
immediate-leave	Enables fast leave on a port.
last-member-query-interval <0–255>	Configures the maximum response time (in tenths of a second) inserted into group-specific queries sent in response to leave group messages. This value is also the time between group-specific query messages. You cannot configure this value for IGMPv1. Decreasing the value reduces the time to detect the loss of the last member of a group. The default is 10 tenths of a second. You should configure this value between 3–10 (equal to 0.3 – 1.0 seconds).
port `{slot/port[/sub-port] [-slot/port[/sub-port]] [,...]}`	Configures IGMP for a specific port. Identifies the slot and port in one of the following formats: a single slot and port (slot/port), a range of slots and ports (slot/port-slot/port), or a series of slots and ports (slot/port,slot/port,slot/port). If the platform supports channelization and the port is channelized, you must also specify the sub-port in the format slot/port/sub-port.
query-interval <1–65535>	Configures the frequency (in seconds) at which the VLAN transmits host query packets. The default value is 125 seconds.
query-max-response <0–255>	Configures the maximum response time (in tenths of a second) advertised in IGMPv2 general queries on this interface. You cannot configure this value for IGMPv1. Smaller values enable a router to prune groups faster. The default is 100 tenths of a second (equal to 10 seconds). Important: You must configure this value lower than the query-interval.
robust-value <2–255>	Configures the expected packet loss of a network. The default value is 2 seconds. Increase the value if you expect the network to experience packet loss.
router-alert	Instructs the router to ignore IGMP packets that do not contain the router alert IP option. When disabled (default configuration), the router processes IGMP packets regardless of the status of the router alert IP option. Important: To maximize network performance, configure this parameter according to the version of IGMP currently in use: IGMPv1—Disable IGMPv2—Enable IGMPv3—Enable
stream-limit stream-limit-max-streams `<0-65535>`	Configures multicast stream limitation on a port to limit the number of concurrent multicast streams on the port. The default is 4.
version <1–3>	Configures the version of IGMP for this interface. For IGMP to function correctly, all routers on a LAN must use the same version. The default value is 2 (IGMPv2).