IGMP/MLD Snooping is Layer 2 functionality but IGMP/MLD are Layer 3 multicast protocols. It requires that in a network setup there should be a multicast router (which can act as a querier) to be present to solicit the multicast group registrations. However some network setup does not need a multicast router as multicast traffic is destined to hosts within the same network. In this situation, the software has an IGMP/MLD Snooping Querier running on one of the switches and Snooping enabled on all the switches. For more information, see "IGMP Snooping Configuration Commands" on page 453 and "MLD Snooping Commands" on page 463.
ipv6 mld router
Use this command, in the administrative mode of the router, to enable MLD in the router.
Default: Disabled
Format: ipv6 mld router
Mode:
Global Config
Interface Config
no ipv6 mld router
Use this command, in the administrative mode of the router, to disable MLD in the router.
Default: Disabled
Format: no ipv6 mld router
Mode: Global Config
ipv6 mld query-interval
Use this command to set the MLD router’s query interval for the interface or range of interfaces. The query-interval is the amount of time between the general queries sent when the router is the querier on that interface. The range for query-interval is 1 to 3600 seconds.
Default: 125
Format: ipv6 mld query-interval query-interval
Mode: Interface Config
no ipv6 mld query-interval
Use this command to reset the MLD query interval to the default value for that interface.
Format: no ipv6 mld query-interval
Mode: Interface Config
ipv6 mld query-max-response-time
Use this command to set the MLD querier’s maximum response time for the interface or range of interfaces and this value is used in assigning the maximum response time in the query messages that are sent on that interface. The range for query-max-response-time is 0 to 65535 milliseconds.
This command resets the MLD query max response time for the interface to the default value.
Format: no ipv6 mld query-max-response-time
Mode: Interface Config
ipv6 mld last-member-query-interval
Use this command to set the last member query interval for an MLD interface or range of interfaces, which is the value of the maximum response time parameter in the group specific queries sent out of this interface. The range for last-member-query-interval is 0 to 65535 milliseconds.
Use this command to reset the last-member-query-intervalparameter of the interface to the default value.
Format: no ipv6 mld last-member-query-interval
Mode: Interface Config
ipv6 mld last-member-query-count
Use this command to set the number of listener-specific queries sent before the router assumes that there are no local members on an interface or range of interfaces. The range for no ipv6 mld last-member-query-interval is 1 to 20.
Use this command to reset the ipv6 mld last-member-query-count last-member-query-count parameter of the interface to the default value.
Format: no ipv6 mld last-member-query-count
Mode: Interface Config
ipv6 mld version
This command configures the version of MLD for an interface. The value for <version> is either 1 or 2.
Default: 2
Format: ipv6 mld version <version>
Mode: Interface Config
no ipv6 mld version
This command resets the version of MLD for an interface to the default value.
Format: no ipv6 mld version
Mode: Interface Config
show ipv6 mld groups
Use this command to display information about multicast groups that MLD reported. The information is displayed only when MLD is enabled on at least one interface. If MLD was not enabled on even one interface, there is no group information to be displayed.
Format: show ipv6 mld groups {unit/slot/port | group-address}
Mode: Privileged EXEC\User EXEC
Group Address: The address of the multicast group.
Interface: Interface through which the multicast group is reachable.
Up Time: Time elapsed in hours, minutes, and seconds since the multicast group has been known.
Expiry Time: Time left in hours, minutes, and seconds before the entry is removed from the MLD membership table.
When group-address is specified, the following fields are displayed for each multicast group and each interface.
Interface: Interface through which the multicast group is reachable.
Group Address: The address of the multicast group.
Last Reporter: The IP Address of the source of the last membership report received for this multicast group address on that interface.
Filter Mode: The filter mode of the multicast group on this interface. The values it can take are include and exclude.
Version 1 Host Timer: The time remaining until the router assumes there are no longer any MLD version-1 Hosts on the specified interface.
Group Compat Mode: The compatibility mode of the multicast group on this interface. The values it can take are MLDv1 and MLDv2.
The following table is displayed to indicate all the sources associated with this group.
Source Address: The IP address of the source.
Uptime: Time elapsed in hours, minutes, and seconds since the source has been known.
Expiry Time: Time left in hours, minutes, and seconds before the entry is removed.
show ipv6 mld interface
Use this command to display MLD-related information for the interface.
Format: show ipv6 mld interface [unit/slot/port]
Mode: Privileged EXEC\User EXEC
The following information is displayed for each of the interfaces or for only the specified interface.
Interface: The interface number in unit/slot/port format.
MLD Mode: Displays the configured administrative status of MLD.
Operational Mode: The operational status of MLD on the interface.
MLD Version: Indicates the version of MLD configured on the interface.
Query Interval: Indicates the configured query interval for the interface.
Query Max Response Time: Indicates the configured maximum query response time (in seconds) advertised in MLD queries on this interface.
Robustness: Displays the configured value for the tuning for the expected packet loss on a subnet attached to the interface.
Startup Query interval: This valued indicates the configured interval between General Queries sent by a Querier on startup.
Startup Query Count: This value indicates the configured number of Queries sent out on startup, separated by the Startup Query Interval.
Last Member Query Interval: This value indicates the configured Maximum Response Time inserted into Group-Specific Queries sent in response to Leave Group messages.
Last Member Query Count: This value indicates the configured number of Group-Specific Queries sent before the router assumes that there are no local members.
The following information is displayed if the operational mode of the MLD interface is enabled.
Querier Status: This value indicates whether the interface is an MLD querier or non-querier on the subnet it is associated with.
Querier Address: The IP address of the MLD querier on the subnet the interface is associated with.
Querier Up Time: Time elapsed in seconds since the querier state has been updated.
Querier Expiry Time: Time left in seconds before the Querier loses its title as querier.
Wrong Version Queries: Indicates the number of queries received whose MLD version does not match the MLD version of the interface.
Number of Joins: The number of times a group membership has been added on this interface.
Number of Leaves: The number of times a group membership has been removed on this interface.
Number of Groups: The current number of membership entries for this interface.
show ipv6 mld traffic
Use this command to display MLD statistical information for the router.
Format: show ipv6 mld traffic
Mode: Privileged EXEC\User EXEC
Valid MLD Packets Received: The number of valid MLD packets received by the router.
Valid MLD Packets Sent: The number of valid MLD packets sent by the router.
Queries Received: The number of valid MLD queries received by the router.
Queries Sent: The number of valid MLD queries sent by the router.
Reports Received: The number of valid MLD reports received by the router.
Reports Sent: The number of valid MLD reports sent by the router.
Leaves Received: The number of valid MLD leaves received by the router.
Leaves Sent: The number of valid MLD leaves sent by the router.
Bad Checksum MLD Packets: The number of bad checksum MLD packets received by the router.
Malformed MLD Packets: The number of malformed MLD packets received by the router.
