Internet Group Management Protocol (IGMP)

Internet Group Management Protocol (IGMP) Overview

IGMP was designed for hosts on multi-access networks to inform locally-attached routers of their multicast group memberships. Hosts inform routers of the groups of which they are members by multicasting IGMP Group Membership Reports. Once multicast routers listen for these reports, they can exchange group membership information with other multicast routers. This reporting system allows distribution trees to be formed to deliver multicast datagrams. The original version of IGMP was defined in RFC 1112, Host Extensions for IP Multicasting. Extensions to IGMP, known as IGMP version 2, include explicit Leave messages for faster pruning and are defined in RFC 2236. Advanced Routing Suite implements IGMP version 2, which includes interoperability with version 1 hosts, and version 3, which includes interoperability with version 2 and version 1 hosts. The original version of IGMP can be found at:

IGMP version 2 is described in:

IGMP version 3 is described in:

clear ip igmp group

Name

clear ip igmp group - removes IGMP join state

Syntax

clear ip igmp group [ group-name || group-address || type || number ]?

Mode

Privileged Execution

Parameters

group-name - the name of the multicast group, as defined in DNS host table. Entering this is optional.

group-address - the IPv4 address of the multicast group in dotted-quad format. Entering this is optional.

type - the interface type. Entering this is optional.

number - the interface number. Entering this is optional.

Description

Use clear ip igmp group to remove IGMP join state. This command has four forms, depending upon whether any or all of the optional parameters are provided. If only the group name or group address is specified, then the associated group entries will be deleted from all interfaces. If only the interface is specified, then all group entries will be deleted for the interface. If neither a group nor an interface is specified, then group memberships over all the IGMP interfaces will be deleted.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example shows a request to clear group entry for 224.1.1.1 on interface 192.168.10.1.

# clear ip igmp group 224.1.1.1 192.168.10.1

Example 2

The following example shows a request to clear group entries for interface Ethernet0/1.

# clear ip igmp group Ethernet0/1

Example 3

The following example shows a request to clear group entries for group 224.1.1.1 on interface Ethernet0/1.

# clear ip igmp group 224.1.1.1 Ethernet0/1

Example 4

The following example, a request is issued to clear the same group entries for group 224.1.1.1 on interface Ethernet0/1, as in Example 3. The difference is that in this example, the interface is specified first, followed by the group.

# clear ip igmp group Ethernet0/1 224.1.1.1

Example 5

The following example issues a request to clear group entry without any parameters. This essentially deletes all group entries over all interfaces.

# clear ip igmp group

ip igmp

Name

ip igmp - enables or disables the IGMP protocol

Syntax

ip igmp

no ip igmp

Mode

Interface Configuration

Parameters

none

Description

The ip igmp configuration enables the IGMP protocol on the associated interface with the default set of configurations. Its "no" form (no ip igmp) disables IGMP on the interface.

Default

IGMP is not run on interfaces by default.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example enables IGMP on interface fxp1 only.

(config)# interface fxp1

(config-if)# ip igmp

Example 2

With the command line still in Interface Configuration Mode for interface fxp1, the following example disables IGMP on that interface.

(config-if)# no ip igmp

(config-if)# exit

(config)#

ip igmp ignore-v1-messages

Name

ip igmp ignore-v1-messages - specifies whether to process IGMPv1 messages on the associated interface(s)

Syntax

ip igmp ignore-v1-messages

no ip igmp ignore-v1-messages

Mode

Interface Configuration

Parameters

none

Description

The ip igmp ignore-v1-messages configuration disables processing of all IGMPv1 messages on the associated interface. Note that this breaks interoperability with older IGMPv1 speakers on the network and should be done when it is important to maintain small group leave latencies.

Note: This configuration is meaningful only when the current version on the interface is IGMPv2 or IGMPv3. A warning will be given if you attempt to configure ignore-v1-messages and the current version is IGMPv1.

The negative form of this command resets the option such that IGMPv1 messages are not ignored.

Default

If ignore-v1-messages is not configured, it is the same as if the user had specified the following:
(config-if)# no ip igmp ignore-v1-messages

Command History

NGC 2.2 - This command was introduced.

Examples

In the following example, ip igmp ignore-v1-messages is used to disable processing of IGMPv1 messages on interface fxp0.

(config)# interface fxp0

(config-if)# ip igmp ignore-v1-messages

(config-if)# exit

(config)#

ip igmp ignore-v2-messages

Name

ip igmp ignore-v2-messages - specifies whether to process IGMPv2 messages on the associated interface(s)

Syntax

ip igmp ignore-v2-messages

no ip igmp ignore-v2-messages

Mode

Interface Configuration

Parameters

none

Description

The ip igmp ignore-v2-messages configuration disables processing of all IGMPv2 messages on the associated interface. Note that this breaks interoperability with older IGMPv2 speakers on the network and should be done when it is important to maintain small group leave latencies.

Note: This configuration is meaningful only when the current version on the interface is IGMPv3. A warning will be given if you attempt to configure ignore-v2-messages and the current version is not IGMPv3.

The negative form of this command resets the option such that IGMPv2 messages are not ignored.

Default

If ignore-v2-messages is not configured, it is the same as if the user had specified the following:
(config-if)# no ip igmp ignore-v2-messages

Command History

NGC 2.2 - This command was introduced.

Examples

In the following example, ip igmp ignore-v2-messages is used to disable processing of IGMPv1 messages on interface fxp0.

(config)# interface fxp0

(config-if)# ip igmp ignore-v2-messages

(config-if)# exit

(config)#

ip igmp last-member-query-count

Name

ip igmp last-member-query-count - specifies the number of queries sent out on startup, separated by the Last Member Query Interval

Syntax

ip igmp last-member-query-count value

no ip igmp last-member-query-count value?

Mode

Global Configuration

Interface Configuration

Parameters

value - an integer between 1 and 65535, inclusive

Description

The command configures the value of the Last Member Query Count as specified in RFC 3376. It specifies the number of queries sent out on startup, separated by the Last Member Query Interval.

The last-member-query-count and its no form configuration can be issued in both Global Configuration and Interface Configuration modes. If this is configured in Global Configuration mode, then it configures the default Last Member Query Count for all interfaces over which IGMP is running. If it is configured in Interface Configuration mode, then it configures the Last Member Query Count for the associated interfaces.

Use the no form of the configuration to return to the default last-member-query-count value. Note: Specifying a value in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If an interface-scoped last-member-query-count is configured, then that configured value is used on the interface. If an interface-scoped last-member-query-count is not configured, then the value used on the interface is the value specified in an interface-scoped robustness. If an interface-scoped robustness is not configured, then the value used on the interface is the value specified in the globally scoped last-member-query-count. If no globally scoped last-member-query-count is configured, then the value used on the interface is the value of the globally scoped robustness. Finally, if no globally scoped robustness is configured, then the value used on the interface is 2.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the Last Member Query Count to be 4.

(config)# ip igmp last-member-query-count 4

Example 2

In the following example, the globally scoped Robustness is configured to be 4. The globally scoped Last Member Query count is configured to be 5. Neither the interface-scoped Robustness nor the interface-scoped Last Member Query Count is configured for interface fxp1. The no ip igmp startup-query-count for fxp1 implies that the globally scoped Last Member Query Count value of 5 will be used on that interface.

(config)# ip igmp robustness 4

(config)# ip igmp last-member-query-count 5

(config)# interface fxp1

(config-if)# no ip igmp startup-query-count

(config-if)# exit

(config)#

ip igmp last-member-query-interval

Name

ip igmp last-member-query-interval - specifies the maximum amount of time that hosts are allowed to respond to Group-Specific query messages

Syntax

ip igmp last-member-query-interval time-milliseconds

no ip igmp last-member-query-interval time-milliseconds?

Mode

Global Configuration

Interface Configuration

Parameters

time-milliseconds - specifies a number of milliseconds. This value can be either 0 or an integer from 1000 to 31744000, inclusive.

Description

The ip igmp last-member-query-interval command configures the length of the Last Member Query Interval - the interval determining the maximum amount of time that hosts are given to respond to Group-Specific or Group-and-Source-Specific queries. This value is encoded in the Max Resp Code field of Group-Specific or Group-and-Source-Specific Query messages and can be either 0 or an integer from 1000 to 31744000, inclusive. Note: The value range 1 to 999 is not permitted.

The Last Member Query Interval configuration and its no form can be issued in both Global Configuration and Interface Configuration modes. If this is configured in Global Configuration mode, then it configures the default Last Member Query Interval for all interfaces over which IGMP is running. If this is configured in Interface Configuration mode, then it configures the Last Member Query Interval for the associated interfaces.

Use the no form of this configuration to return to the default value of the Last Member Query Interval. Note: Specifying a value for time-milliseconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If ip igmp last-member-query-interval is not specified, it is the same as if the user had entered the following:

(config)# ip igmp last-member-query-interval 1000
or
(config-if)# ip igmp last-member-query-interval 1000

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the default Last Member Query Interval to be 2000 milliseconds (20 seconds)

(config)# ip igmp last-member-query-interval 2000

Example 2

The following example configures the default Last Member Query Interval to be 3000 milliseconds. This value is then overridden in interface fxp0, where it is configured to be 2000 milliseconds. The no ip igmp last-member-query-interval for interface fxp1 implies that the configured default value of 3000 will be used on that interface.

(config)# ip igmp last-member-query-interval 3000

(config)# interface fxp0

(config-if)# ip igmp last-member-query-interval 2000

(config-if)# exit

(config)# interface fxp1

(config-if)# no ip igmp last-member-query-interval

(config-if)# exit

(config)#

ip igmp query-interval

Name

ip igmp query-interval - specifies the value of the query interval in seconds

Syntax

ip igmp query-interval time-seconds

no ip igmp query-interval time-seconds?

Mode

Global Configuration

Interface Configuration

Parameters

time-seconds - specifies a number in seconds between 1 and 3174, inclusive. Note: This value cannot be less than the Query Response Interval.

Description

This command specifies the value of the Query Interval in seconds. The Query Interval is the interval between General Queries sent by the Querier. It is encoded in the Query Interval Code (QQIC) field of General Queries. The Query Interval cannot be less than the Query Response Interval (configured using ip igmp query-response-interval). The maximum value of the Query Interval is 3174 seconds.

The Query Interval configuration and its no form configuration can be issued in both Global Configuration Mode and Interface Configuration Mode. If it is configured in Global Configuration Mode, it configures the default Query Interval for all interfaces over which IGMP is running. If it is configured in Interface Configuration Mode (in other words, at the (config-if)# prompt), then it configures the Query Interval for the associated interfaces.

Use the no form of the configuration to return to the default value of 125 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If ip igmp query-interval is not specified, it is the same as if the user had specified the following:
(config)# ip igmp query-interval 125
or
(config-if)# ip igmp query-interval 125

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the default Query Interval for all interfaces to be 200 seconds.

(config)# ip igmp query-interval 200

Example 2

The following example configures the default Query Interval to be 200 seconds and the Query Interval for interface fxp0 to be 210 seconds. The no igmp query-interval command for fxp1 implies that the configured default value of 200 seconds will be used on that interface.

(config)# ip igmp query-interval 200

(config)# interface fxp0

(config-if)# ip igmp query-interval 210

(config-if)# exit

(config)# interface fxp1

(config-if)# no ip igmp query-interval

ip igmp query-max-response-time

Name

ip igmp query-max-response-time - configures the maximum amount of time allowed before a host sends a report message

Syntax

ip igmp query-max-response-time time-seconds

no ip igmp query-max-response-time time-seconds?

Mode

Global Configuration

Interface Configuration

Parameters

time-seconds - a number between 0 and 3174 seconds, inclusive. Note: This value must be less than or equal to the Query Interval.

Description

The ip igmp query-max-response-time command configures the length of the Query Response Interval, the maximum amount of time allowed before a Host sends a Report message in response to a received General Query. This interval is encoded in the Max Resp Code field of General Query messages. The interval can have a value from 0 to 3174 seconds. This value must be less than or equal to the Query Interval.

The ip igmp query-max-response-time command and its no form can be issued in both Global Configuration Mode and Interface Configuration Mode. When issued in Global Configuration Mode, it configures the default Query Response Interval for all interfaces over which IGMP is running. If it is configured in Interface Configuration Mode, it configures the Query Response Interval for the associated interfaces.

Use the no form of the configuration to return to the default value of 10 seconds. Note: Specifying a value for time-seconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Note: There is forward and backward conversion between the Advanced Routing Suite CLI and the Advanced Routing Suite XML for this item. The equivalent XML command, <query-response-interval>, is configured in units of deciseconds. When this value is configured in the Advanced Routing Suite CLI, the CLI converts it from seconds to deciseconds before sending the configuration to XML. Then, in show running, the CLI receives deciseconds from the XML configurator and converts it back to seconds, rounding it down to the nearest second. For example, if this value is configured in XML as 31712 deciseconds, then it will be read in the CLI as 3171 seconds.

Default

If ip igmp query-max-response-time is not specified, it is the same as if the user had specified the following:

(config)# ip igmp query-max-response-time 10
or
(config-if)# ip igmp query-max-response-time 10

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the default Query Response Interval to be 10 seconds (or 100 deciseconds).

(config)# ip igmp query-max-response-time 100

Example 2

The following example configures the default Query Response Interval to be 11 seconds and the Query Response Interval for interface fxp0 to be 12 seconds. The no ip igmp query-max-response-time command for fxp1 implies that the configured default value of 110 deciseconds will be used on that interface.

(config)# ip igmp query-max-response-time 110

(config)# interface fxp0

(config-if)# ip igmp query-max-response-time 120

(config-if)# exit

(config)# interface fxp1

(config-if)# no ip igmp query-max-response-time

ip igmp require-router-alert

Name

ip igmp require-router-alert - specifies whether to ignore messages that do not contain the Router Alert option, thereby improving protocol security

Syntax

ip igmp require-router-alert

no ip igmp require-router-alert

Mode

Global Configuration

Interface Configuration

Parameters

none

Description

The require-router-alert configuration specifies whether to ignore messages that do not container the Router Alert option, thereby improving protocol security. If this command is configured, then the following messages are ignored if they do not contain the Router Alert option:

• State-Change Report
• Current-State Report
• Leave Message in IGMP version 2 mode
• Report Message in IGMP version 2 mode

This configuration and its no form configuration can be issued in both Global Configuration and Interface Configuration modes. If this is configured in Global Configuration mode, then it configures the default for all interfaces over which IGMP is running. If it is configured in Interface Configuration mode, then it configures the parameter for the associated interfaces.

Use the no form configuration to return to the default value.

Default

If require-router-alert is not specified, it is the same as if the user had specified the following:

(config)# ip igmp require-router-alert
or
(config-if)# ip igmp require-router-alert

Command History

NGC 2.2 - This command was introduced.

NGC 2.3 - The default for this command changed from off to on.

Examples

The following example turns require-router-alert off for interface fxp0 and on for all other interfaces.

(config)# interface fxp0

(config-if)# no ip igmp require-router-alert

(config-if)# exit

(config)# ip igmp require-router-alert

ip igmp robustness

Name

ip igmp robustness - allows for tuning of the IGMP protocol or interface to accommodate a lossy subnet

Syntax

ip igmp robustness value

no ip igmp robustness value?

Mode

Global Configuration

Interface Configuration

Parameters

value - an integer between 2 and 7, inclusive

Description

The ip igmp robustness command allows you to tune IGMP for the expected loss on a network. IGMP is robust to (Robustness - 1) packet losses, and this value is advertised in the Querier’s Robustness Variable (QRV) field of Query.

The ip igmp robustness configuration and its no form can be issued in both Global Configuration and Interface Configuration modes. If this command is configured in Global Configuration mode, it configures the default Robustness for all interfaces over which IGMP is running. If it is configured in Interface Configuration mode, it configures the Robustness for the associated interfaces.

Use the no form of this configuration to return to the default value of Robustness. Note: Specifying a value in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If ip igmp robustness is not specified, it is the same as if the user had specified the following:

(config)# ip igmp robustness 2
or
(config-if)# ip igmp robustness 2

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the default Robustness to be 3.

(config)# ip igmp robustness 3

Example 2

The following example configures the default Robustness to be 3 and the Robustness for interface fxp0 to be 4. The no ip igmp robustness for interface fxp1 implies that the configured default value of 3 will be used on that interface.

(config)# ip igmp robustness 3

(config)# interface fxp0

(config-if)# ip igmp robustness 4

(config-if)# exit

(config)# interface fxp1

(config-if)# no ip igmp robustness

ip igmp send-router-alert

Name

ip igmp send-router-alert - specifies whether sent IGMP packets will include the Router Alert option in the IP packet header

Syntax

ip igmp send-router-alert

no ip igmp send-router-alert

Mode

Global Configuration

Interface Configuration

Parameters

none

Description

Use the ip igmp send-router-alert option to specify that sent packets should include the router alert option in the IP packet header.

Default

If ip igmp send-router-alert is not specified, it is the same as if the user had specified the following:
(config)# no ip igmp send-router-alert
or
(config-if)# no ip igmp send-router-alert

Command History

NGC 2.2 - This command was introduced.

Examples

The following example turns the send-router-alert option on for all of IGMP, then explicitly turns it off for interface fxp1.

(config)# ip igmp send-router-alert

(config)# interface fxp1

(config-if)# no ip igmp send-router-alert

(config-if)# exit

(config)#

ip igmp startup-query-count

Name

ip igmp startup-query-count - specifies the number of queries sent out on startup, separated by the Startup Query Interval

Syntax

ip igmp startup-query-count value

no ip igmp startup-query-count value?

Mode

Global Configuration

Interface Configuration

Parameters

value - an integer between 1 and 65535, inclusive

Description

This configuration specifies the value of the Startup Query Count as specified in RFC 236 and RFC 3376. It configures the number of queries sent out on startup, separated by the Startup Query Interval. The number of queries can be an integer between 1 and 65535, inclusive.

This configuration, and its no form configuration can be issued in both Global Configuration and Interface Configuration modes. If this is configured in Global Configuration mode, then it configures the default Startup Query Count for all interfaces over which IGMP is running. If it is configured in Interface Configuration mode, then it configures the Startup Query Count for the associated interfaces.

Use the no form of this configuration to return to the default value of Startup Query Count. Note: Specifying a value in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If an interface-scoped startup-query-count is configured, then the configured value is used on the interface. If an interface-scoped startup-query-count is not configured, then the value used on the interface is the value specified in an interface-scoped robustness. If an interface-scoped robustness is not configured, then the value used on the interface is the value specified in the globally scoped startup-query-count. If no globally scoped startup-query-count is configured, then the value used on the interface is the value of the globally scoped robustness. Finally, if no globally scoped robustness is configured, then the value used on the interface is 2.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the globally scoped Startup Query Count to be 4.

(config)# ip igmp startup-query-count 4

Example 2

In the following example, the globally scoped Robustness value is configured to be 4. The no ip igmp startup-query-count for interface fxp1 implies that the globally scoped Robustness value of 4 will be used on that interface.

(config)# ip igmp robustness 4

(config)# interface fxp1

(config-if)# no ip igmp startup-query-count

(config-if)# exit

(config)#

ip igmp startup-query-interval

Name

ip igmp startup-query-interval - specifies the time between successive General Query messages on startup.

Syntax

ip igmp startup-query-interval time-deciseconds

no ip igmp startup-query-interval time-deciseconds?

Mode

Global Configuration

Interface Configuration

Parameters

time-deciseconds - a number in tenths of a second between 10 and 317440

Description

This command configures the value of the Startup Query Interval as specified in RFC3376. This parameter determines the time between successive General Query messages on startup. This value is expressed in units of deciseconds (1/100 of a second) and is encoded in the Max Resp Code field of Query messages. The range of this parameter is 10 to 317440 deciseconds. All values between 10 and 1270 deciseconds are exactly configurable. Above 1270 deciseconds, only intervals for which integer values of 'e' and 'm' exist to satisfy the equation below are exactly configurable.

interval = (16 + m) * 2^(e + 3)

where

0 <= e <= 7

0 <= m <= 15

If no values of m and e exist to exactly represent the configured value, then Advanced Routing Suite will round down to the next lower, representable value is used.

The Startup Query Configuration and its no form configuration can be issued in both Global Configuration and Interface Configuration modes. If this is configured in Global Configuration mode, then it configures the default Startup Query Interval for all interfaces over which IGMP is running. If this is configured in Interface Configuration mode, then it configures the Startup Query Interval for the associated interface.

Use the no form of this configuration to return to the default value of Startup Query Interval. Note: Specifying a value for deciseconds in the no form has no effect on the configuration. Thus, it is displayed above as optional.

Default

If an interface-scoped startup-query-interval is configured, then the configured value is used on the interface. If an interface-scoped startup-query-interval is not configured, then the value used on the interface is one-fourth (1/4) the value specified in an interface-scoped query-interval. If an interface-scoped query-interval is not configured, then the value used on the interface is the value specified in the globally scoped startup-query-interval. If no globally scoped startup-query-interval is configured, then the value used on the interface is one-fourth the value of the globally scoped query-interval. Finally, if no globally scoped query-interval is configured, then the value used on the interface is 31 seconds.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the default Startup Query Interval to be 120 deciseconds (12 seconds).

(config)# ip igmp startup-query-interval 120

Example 2

The following example, the default Startup Query Interval is configured to be 120 deciseconds. The Startup Query Interval for interface fxp0 is configured to be 110 deciseconds. The no ip igmp startup-query-interval for fxp1 implies that the globally scoped Startup Query Interval value of 120 will be used on that interface.

(config)# ip igmp startup-query-interval 120

(config)# interface fxp0

(config-if)# ip igmp startup-query-interval 110

(config-if)# exit

(config)# interface fxp1

(config-if)# no ip igmp startup-query-interval

Example 3

In the following example, an attempt is made to configure the Startup Query Interval for fxp0 to 274. No values of m and e satisfy the equation below.

247 = (16 + m) * 2^(e + 3)

Therefore, the value that Advanced Routing Suite will actually use will be the next lowest representable value, 272 (m = 1, e = 1)

Attempted configuration:

(config)# interface fxp0

(config-if)# ip igmp startup-query-interval 274

(config-if)# exit

(config)#

See Also

"ip igmp query-interval"

ip igmp static-group

Name

ip igmp static-group - causes the router to establish a static join to the multicast group

Syntax

ip igmp static-group group-address [ source source-address ]?

no ip igmp static-group group-address [ source source-address ]?

Mode

Interface Configuration

Parameters

group group-address - a valid multicast group address in dotted-quad notation

source source-address - a valid multicast source addresses in dotted-quad notation. Specifying this is optional. Note that when specifying a source address, the source keyword is required.

Description

The ip igmp static-group command causes the router to establish a static join to the multicast group. Note that the group is not actually joined. In other words, no IGMP messages are triggered in response to this command. Instead, this command causes multicast routing to behave as if there were a local member of the indicated group (and source) reachable via the associated interface.

The group-address value is the address of the multicast group in dotted-quad notation. The source keyword allows you to specify a (source, group) pair to be forwarded out of the interface if the group is within the SSM range.

Use the negative form of this command, no ip igmp static-group, to cancel a static join for a multicast group.

Default

none

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example configures the router to join group 224.1.1.1 on interface fxp0.

(config)# interface fxp0

(config-if)# ip igmp static-group 224.1.1.1

(config-if)# exit

(config)#

Example 2

In the following example, the router is configured to cancel its membership for group 224.1.1.1.

(config)# interface fxp0

(config-if)# no ip igmp static-group

(config-if)# exit

(config)#

Example 3

In the following example, the router is configured to forward packets from source 192.168.11.1 for group 232.1.1.1 on interface fxp0.

(config)# interface fxp0

(config-if)# ip igmp static-group 232.1.1.1 source 192.168.11.1

(config-if)# exit

(config)#

ip igmp trace file

Name

ip igmp trace file - specifies file options when tracing in IGMP

Syntax

ip igmp trace file file_name [no-timestamp || overwrite]?

no ip igmp trace file name file_name [no-timestamp || overwrite]?

Mode

Global Configuration

Parameters

file_name - specifies the name of the file to receive the tracing information. Note that the file name is not specified in quotes.

no-timestamp - specifies that a timestamp should not be prepended to all trace lines

overwrite - specifies to begin tracing by appending or truncating an existing file

Description

The trace file command is associated with each protocol, so that information pertaining to a single protocol can be written to its own file. For IGMP, the ip igmp trace file command specifies a file for tracing of all IGMP events. The negative form of this command disables this tracing. The specific events that are traced are controlled by the ip igmp trace flag command.

The no-timestamp option disables the pre-pending of a timestamp to all lines written to the trace file. The default is to prepend a timestamp to all lines written to a trace file.

The overwrite option specifies whether to start tracing by truncating or appending to an existing file.

Note: These options are not cumulative across multiple commands. Consider the following example:

(config)# ip igmp trace file /var/log/igmp.log no-timestamp

(config)# ip igmp trace file /var/log/igmp.log

The option given in the second command completely replaces that given in the first.

Default

IGMP tracing is turned off by default.

Command History

NGC 2.2 - This command was introduced.

Examples

In the following example, IGMP tracing is written to the file "/var/tmp/igmp.log"(config)# ip igmp trace file /var/tmp/igmp.log

ip igmp trace flag

Name

ip igmp trace flag - specifies IGMP-specific tracing options as well as options that are common across all protocols

Syntax

ip igmp trace flag ( [ route | normal | state | policy |
task | timer | all ] ) | ( [ query | report | leave |
packets ] [ send | receive | send-receive ]? [detail?] )

no ip igmp trace flag ( [ route | normal | state |
policy | task | timer | all ] ) | ( [ query | report |
leave | packets ] [ send | receive | send-receive ]? [detail?] )

Mode

Global Configuration

Parameters

Flags common to all protocols:

[ route | normal | state | policy | task | timer | all ] - These tracing flags are common to all protocols. They cannot be associated with a send, receive, or send-receive action item. Similarly, you cannot specify to show detailed information when tracing these flags. These flags are defined as follows:

• route - trace routing table changes for routes installed by this protocol or peer
• normal - trace normal protocol occurrences. Note: Abnormal protocol occurrences are always traced.
• state - trace state machine transition in the protocol
• policy - trace the application of protocol and user-specified policy to routes being imported or exported
• task - trace system interface and processing associated with this protocol
• timer - trace timer usage by this protocol
• all - turns on all trace flags

IGMP-specific flags:

[ leave | query | report | packets ] - The IGMP-specific flags can be associated with the send, receive, or send-receive action items. These flags are defined as follows:

• leave - trace all IGMPv3 Leave messages.
• query - trace IGMPv3 Membership Query messages.
• report - trace IGMPv3 Membership Report messages.
• packets - trace all IGMPv3 packets

[ send | receive | send-receive ]? - optionally specify whether to limit the tracing to packets sent, received, or both

[detail?] - optionally specify to use a more verbose format when displaying information about the contents of packets instead of one or two lines

Description

Use the ip igmp trace flag command to specify tracing flags for IGMP tracing. Each flag must reside on its own configuration line. For example, you cannot specify to trace both query and leave packets in the same command.

Default

The default is for no flags to be explicitly configured.

Command History

NGC 2.2 - This command was introduced.

Examples

In the following example, trace flags specify that both the sent and received query and report messages are traced in detail. This tracing information will be written to the file /var/tmp/igmp.log.

(config)# ip igmp trace file /var/tmp/igmp.log

(config)# ip igmp trace flag query send-receive detail

(config)# ip igmp trace flag report send-receive detail

ip igmp version

Name

ip igmp version - specifies the version of IGMP to run

Syntax

ip igmp version [ 1 | 2 | 3 ]

no ip igmp version

Mode

Interface Configuration

Parameters

1 | 2 | 3 - specifies whether to run version 1, version 2, or version 3 of IGMP

Description

Use the ip igmp version configuration to specify the version of IGMP that you want to run.

Default

If ip igmp version is not specified, it is the same as if the user had specified the following:

(config-if)# ip igmp version 3

Command History

NGC 2.2 - This command was introduced.

Examples

The following example configures IGMP version 2 to run on interface fxp0.

(config)# interface fxp0

(config-if)# ip igmp version 2

(config-if)# exit

(config)#

show ip igmp groups

Name

show ip igmp groups - displays IGMP information regarding multicast group membership

Syntax

show ip igmp groups [group-name || interface
(ipv4_address | interface_name)] [detail]?

show ip igmp groups [group-address || interface
(ipv4_address | interface_name)] [detail]?

Mode

Privileged Execution

Parameters

group-name - the name of the multicast group, as defined in DNS host table. If a group-name is specified, an optional interface can also be specified to view group information for that interface.

group-address - the IPv4 address of the multicast group in dotted-quad format. Entering this is optional. If a group-address is specified, an optional interface can also be specified to view group information for that interface.

interface (ipv4_address | interface_name) - optionally specify to view information for a specific interface or for a specific interface within a specific group

detail - displays IGMPv3 style group information and source information. Entering this is optional. Otherwise, IGMPv2 style group information is given.

Description

Use show ip igmp groups to obtain IGMP information regarding multicast group membership. Queries can be submitted in multiple forms, as shown in the examples that follow. If a query is issued without specifying a group, then group membership information for all groups that are connected to this router will be returned. Alternatively, a query can be issued with the name of the multicast group, the IPv4 address of the multicast group, and/or the interface specified, with or without the detail option. If detail is specified, the response will contain IGMPv3 specific information, including the group mode and other source information.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example queries information pertaining to IGMP or all groups on all interfaces.

# show ip igmp groups

IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
224.1.1.1 fxp1 00:00:32 00:01:32 10.2.25.159
224.1.1.1 fxp0 00:00:33 00:01:33 10.2.12.31
224.1.1.2 fxp0 00:00:32 00:01:32 10.2.12.31
224.1.1.3 fxp1 00:00:31 00:01:31 10.2.25.159

Example 2

The following example is a query for group information pertaining to IGMP for multicast group 224.1.1.1.

# show ip igmp groups 224.1.1.1

IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
224.1.1.1 fxp1 00:01:30 00:02:30 10.2.25.159
224.1.1.1 fxp0 00:01:31 00:02:31 10.2.12.31

Example 3

The following query requests group information pertaining to IGMP for interface eth1.

# show ip igmp groups interface eth1

IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
224.1.1.1 fxp0 00:02:20 00:03:20 10.2.12.31
224.1.1.2 fxp0 00:02:19 00:03:19 10.2.12.31

Example 4

The following query is a request for group information pertaining to group 224.1.1.1 on interface eth1.

# show ip igmp groups 224.1.1.1 interface eth1

IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter
224.1.1.1 fxp0 00:02:57 00:03:57 10.2.12.31

Example 5

The following example is a query for group information pertaining to IGMP in detail for all groups on all interfaces.

# show ip igmp groups detail

IGMP connected Group Membership
Interface: Ethernet0/1 (192.168.11.1)
Group: 224.1.1.1
Uptime: 00:00:34
Expires: 00:00:40
Last reporter: 192.168.11.2
Last-member-query-counter: 1
Last-member-query-timer-expiry: off
Group mode: EXCLUDE
Version1-host-present-timer-expiry: 00:00:20
Version2-host-present-timer-expiry: off
Source list is empty

Interface: Ethernet0/2 (192.168.12.1)
Group: 224.2.2.2
Uptime: 00:00:34
Expires: 00:00:40
Last reporter: 192.168.12.2
Last-member-query-timer-expiry: off
Group mode: EXCLUDE
Version1-host-present-timer-expiry: 00:00:20
Version2-host-present-timer-expiry: off
Source list is empty

Interface: Etherent0/2 (192.168.13.1)
Group: 224.3.3.3
Uptime: 00:00:34
Expires: 00:00:40
Last reporter: 192.168.13.2
Last-member-query-counter: 0
Last-member-query-timer-expiry: off
Group mode: INCLUDE
Version1-host-present-timer-expiry: 00:00:20
Version2-host-present-timer-expiry: off
Source list:
Source: 10.1.1.1
Uptime: 00:00:34
Expires: 00:00:40
Last reporter: 192.168.13.2
Last-member-query-counter: 0
Last-member-query-timer-expiry: off

Source: 10.11.11.11
Uptime: 00:00:34
Expires: 00:00:40
Last reporter: 192.168.13.2
Last-member-query-counter: 1
Last-member-query-timer-expiry: 00:00:05

Example 6

In the following example, group information pertaining to group 224.1.1.1 on interface eth3, in detail, is requested.

# show ip igmp groups 224.1.1.1 interface eth3 detail

IGMP connected Group Membership
Interface: Ethernet0?1 (192.168.13.2)
Group: 224.1.1.1
Uptime: 00:00:34
Expires: 00:00:40
Last reporter: 192.168.13.2
Last-member-query-counter: 0
Last-member-query-timer-expiry: off
Group mode: INCLUDE
Version1-host-present-timer-expiry: 00:00:20
Version2-host-present-timer-expiry: off
Source list
Source: 10.3.3.3
Uptime: 00:00:34
Expires: 00:00:40
Last reporter: 192.168.13.2
Last-member-query-counter: 0
last-member-query-timer-expiry: off

Source: 10.33.33.33
Uptime: 00:00:34
Expires: 00:00:40
Last reporter: 192.168.13.2
Last-member-query-counter: 1
Last-member-query-timer-expiry: 00:00:02

Example 7

In the following example, group information in details pertaining to group 224.1.1.1 on interface eth3 is requested. The response indicates that IGMP is not running on the router.

# show ip igmp groups 224.1.1.1 interface eth3 detail

IGMP is not running.

Field Descriptions

The following table describes the fields that appear in the IGMP Group Information Query.

show ip igmp interface

Name

show ip igmp interface - displays multicast-related information about a specific interface or all interfaces

Syntax

show ip igmp interface [ interface-name | ipv4_address ]?

Mode

User Execution

Parameters

interface-name - optionally specify a physical interface

ipv4_address - optionally specify the logical interface address

Description

The show ip igmp interface query displays multicast-related information about a specific interface or all interfaces.

This query has two forms. If the query is issued without arguments, then information on about all interfaces over which IGMP is running is returned. Alternatively, the query can be issued with a specific interface. If this is the case, then the reply will contain information pertaining only to that referenced interface.

Note that if interfaces are added to the set of interfaces over which IGMP is running after this query has been issued but before the query is finished, it is not guaranteed that the new interfaces will be reported. Similarly, if IGMP is de-configured on an interface after the query has been issued but before the query is finished, then the interface may or may not be reported.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example displays interface information for all interfaces on which IGMP is running.

# show ip igmp interface

eth0 is up
Internet address: 10.129.10.26/9
IGMP on this interface: disabled
Multicast routing on this interface: disabled
Multicast TTL threshold: 0
Multicast groups joined: 0

eth1 is up
Internet address: 192.168.11.1/24
IGMP on this interface: enabled
Current IGMP router version: 2
IGMP query interval: 60 seconds
IGMP max query response time: 10 seconds
Last member query response interval: 1000 ms
IGMP activity: 1 joins, 0 leaves
Multicast routing on this interface: enabled
Multicast TTL threshold: 0
Multicast designated router (DR): 192.168.11.1 (this
system)
IGMP Querier: 192.168.11.1 (this system)
Robustness: 2
Require-router-alert: no
Last-member-query-interval: 30 deciseconds
Startup-query-interval: 300 deciseconds
Startup-query-count: 2
General-query-timer-expiry: 00:00:20 (hours:minutes:
seconds)
Startup-query-timer-expiry: off
Other-querier-present-timer-expiry: off
Multicast groups joined (number of users):
224.0.0.2(1)
224.1.1.1(1)

fxp0 is up
Internet address: 192.168.12.1/24
IGMP on this interface: enabled
Current IGMP router version: 3
IGMP query interval: 125 seconds
IGMP max query response time: 10 seconds
Last member query response interval: 1000 ms
IGMP activity: 1 joins, 0 leaves
Multicast routing on this interface: enabled
Multicast TTL threshold: 0
Multicast designated router (DR): 1922.168.12.1 (this
system)
IGMP Querier: 129.168.12.1 (this system)
Robustness: 2
Require-router-alert: no
Last-member-query-interval: 30 deciseconds
Startup-query-interval: 300 deciseconds
Startup-query-count: 2
General-query-timer-expiry: 00:00:20 (hours:minutes:
seconds)
Startup-query-timer-expiry: off
Other-querier-present-timer-expiry: off
Multicast groups joined (number of users):
224.0.0.2(1)
224.2.2.2(1)

Example 2

In the following example, a query is issued for interface eth1 only. The reply indicates that IGMP is running on this interface, and it has two groups joined.

# show ip igmp interface eth1

eth1 is up
Internet address: 192.168.11.1/24
IGMP on this interface: enabled
Current IGMP router version: 2
IGMP query interval: 60 seconds
IGMP max query response time: 10 seconds
Last member query response interval 1000 ms
IGMP activity: 1 joins, 0 leaves
Multicast routing on this interface: enabled
Multicast TTL threshold: 0
Multicast designated router (DR): 192.168.11.1 (this
system)
IGMP Querier: 192.168.11.1
Robustness: 2
Require-router-alert: no
Last-member-query-interval: 30 deciseconds
Startup-query-interval: 300 deciseconds
Startup-query-count: 2
General-query-timer-expiry: 00:00:20 (hours:minutes:
seconds)
Startup-query-timer-expiry: off
Other-querier-present-timer-expiry: off
Multicast groups joined (number of users)
224.0.0.2(1)
224.1.1.1(1)

Example 3

In the following example, a query is issued for interface eth2 only. The reply indicates that IGMP is not running on the router.

# show ip igmp interface eth2

IGMP is not running

Field Descriptions

The following table describes the fields that appear in the IGMP Interface Information Query.

show ip igmp interface-summary

Name

show ip igmp interface-summary - displays simple summary information pertaining to IGMP interfaces

Syntax

show ip igmp interface-summary

Mode

User Execution

Parameters

none

Description

The show ip igmp interface-summary command displays the number of interfaces on which IGMP is running.

Command History

NGC 2.2 - This command was introduced.

Examples

Example 1

The following example issues an interface summary query. The response indicates that IGMP is running on five interfaces.

# show ip igmp interface-summary

Number of active interfaces: 5

Example 2

The following example issues an interface summary query on a router on which IGMP is not running.

# show ip igmp interface-summary

IGMP is not running

show ip igmp static-groups

Name

show ip igmp static-groups - displays IGMP information regarding multicast static-group state

Syntax

show ip igmp static-groups

Mode

User Execution

Parameters

none

Description

The show ip igmp static-groups query displays information about all configured IGMP multicast static groups.

Command History

NGC 2.2 - This command was introduced.

Examples

The following example displays information pertaining to IGMP for all groups on all interfaces.

> show ip igmp static-groups

IGMP CONNECTED Static-Group Membership
Group Address Interface Expires Last Reporter
224.1.1.1 fxp1 never 0.0.0.0
224.1.1.1 fxp0 never 0.0.0.0
224.1.1.2 fxp0 never 0.0.0.0
224.1.1.3 fxp1 never 0.0.0.0