Chapter 25 Configuring IPv6 MLD Snooping

Configuring IPv6 MLD Snooping

The number of MASQs generated is configured by using the ipv6 mld snooping last-listener-query count global configuration command. The default number is 2.

The MASQ is sent to the IPv6 multicast address for which the Done message was sent. If there are no reports sent to the IPv6 multicast address specified in the MASQ during the switch maximum response time, the port on which the MASQ was sent is deleted from the IPv6 multicast address database. The maximum response time is the time configured by using the ipv6 mld snooping last-listener-query-intervalglobal configuration command. If the deleted port is the last member of the multicast address, the multicast address is also deleted, and the switch sends the address leave information to all detected multicast routers.

Topology Change Notification Processing

When topology change notification (TCN) solicitation is enabled by using the ipv6 mld snooping tcn query solicit global configuration command, MLDv1 snooping sets the VLAN to flood all IPv6 multicast traffic with a configured number of MLDv1 queries before it begins sending multicast data only to selected ports. You set this value by using the ipv6 mld snooping tcn flood query count global configuration command. The default is to send two queries. The switch also generates MLDv1 global Done messages with valid link-local IPv6 source addresses when the switch becomes the STP root in the VLAN or when it is configured by the user. This is same as done in IGMP snooping.

MLD Snooping in Switch Stacks

The MLD IPv6 group and MAC address databases are maintained on all switches in the stack, regardless of which switch learns of an IPv6 multicast group. Report suppression and proxy reporting are done stack-wide. During the maximum response time, only one received report for a group is forwarded to the multicast routers, regardless of which switch the report arrives on.

The election of a new stack master does not affect the learning or bridging of IPv6 multicast data; bridging of IPv6 multicast data does not stop during a stack master re-election. When a new switch is added to the stack, it synchronizes the learned IPv6 multicast information from the stack master. Until the synchronization is complete, data ingressing on the newly added switch is treated as unknown multicast data.

Configuring IPv6 MLD Snooping

These sections describe how to configure IPv6 MLD snooping:

Default MLD Snooping Configuration, page 25-6

MLD Snooping Configuration Guidelines, page 25-6

Enabling or Disabling MLD Snooping, page 25-7

Configuring a Static Multicast Group, page 25-8

Configuring a Multicast Router Port, page 25-8

Enabling MLD Immediate Leave, page 25-9

Configuring MLD Snooping Queries, page 25-10

Disabling MLD Listener Message Suppression, page 25-11

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

 

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Cisco Systems 3750E Configuring IPv6 MLD Snooping, Topology Change Notification Processing, MLD Snooping in Switch Stacks