Configuring MLD Settings for an Interface

When you start MLD on an interface, it operates with the default settings. You can, however, modify:

• The method that the router uses to remove hosts from multicast groups
• The time interval at which the querier sends multicast listener queries
• The time that a querier waits before sending a new query to hosts from which it receives multicast listener done messages
• The time that a non-querier waits for queries from the current querier before sending query messages to assume responsibility of querier
• The time that a host can take to reply to a query (maximum response time)
• The number of times that the router sends each MLD message from this interface

ipv6 mld immediate-leave

• Use to specify that, when the router receives a multicast listener done message from a host associated with this interface, the router immediately removes that host from the multicast group.

  Caution: Issue this command only on MLD interfaces to which one MLD host is connected. If more than one MLD host is connected to a LAN through the same interface, and one host sends a done message, the router removes all hosts on the interface from the multicast group. The router loses contact with the hosts that should remain in the multicast group until they send join requests in response to the router's next general multicast listener query.

• Use the MLD-Immediate-Leave RADIUS attribute (VSA 26-100) in RADIUS Access-Accept messages as an alternative method of configuring this value. The RADIUS setting takes precedence over a CLI setting.
• Example

  host1:boston(config-if)#ipv6 mld immediate-leave

• Use the no version to restore the default behavior, in which the router removes a host from a multicast group if that host does not return a multicast listener report within a certain length of time after receiving a multicast listener query from the router.
• See ipv6 mld immediate-leave.

ipv6 mld last-member-query-interval

• Use to specify the last-member-query-interval value, in the range 1–255 tenths of a second. When the router receives an MLDv1 leave message or an MLDv2 state change report, it sends out a query and expects a response within the time specified by this value.
• Using a lower value allows members to leave groups more quickly.
• Example

  host1:boston(config-if)#ipv6 mld last-member-query-interval 90

• Use the no version to restore the default, 10-tenths of a second (1 second).
• See ipv6 mld last-member-query-interval.

ipv6 mld querier-timeout

• Use to set the time, in the range 1–400 seconds, that the interface waits for queries from the current querier before sending query messages to assume responsibility of querier.
• Example

  host1:boston(config-if)#ipv6 mld querier-timeout 200

• Use the no version to set the time to the default, twice the query interval.
• See ipv6 mld querier-timeout.

ipv6 mld query-interval

• Use to specify how often, in the range 1–300 seconds, the interface sends group membership queries.
• Use the MLD-Query-Interval RADIUS attribute (VSA 26-98) in RADIUS Access-Accept messages as an alternative method of configuring this value. The RADIUS setting takes precedence over a CLI setting.
• Example

  host1:boston(config-if)#ipv6 mld query-interval 100

• Use the no version to set the polling interval to the default, 125 seconds.
• See ipv6 mld query-interval.

ipv6 mld query-max-response-time

• Use to specify the period in tenths of a second during which the host is expected to respond to a group membership query. The possible period ranges are as follows:
  • IGMPv1 and IGMPv2: 1–255 tenths of a second
  • IGMPv3: 1–31744 tenths of a second
• MLDv1 and MLDv2 include this value in MLD query messages sent out on the interface.
• Using a lower value allows members to join and leave groups more quickly.
• Use the MLD-Query-Max-Resp-Time RADIUS attribute (VSA 26-99) in RADIUS Access-Accept messages as an alternative method of configuring this value. The RADIUS setting takes precedence over a CLI setting.
• Example

  host1:boston(config-if)#ipv6 mld query-max-response-time 120

• Use the no version to restore the default, 100 tenths of a second (10 seconds).
• See ipv6 mld query-max-response-time.

ipv6 mld robustness

• Use to specify the number of times that the router sends each MLD message from this interface.
• Use a higher value to ensure high reliability from MLD.
• Specify a number in the range 1–4.
• Example

  host1:boston(config-if)#ipv6 mld robustness 2

• Use the no version to restore the default, 3.
• See ipv6 mld robustness.

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