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Cisco IE 2000 Switch Software Configuration Guide
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Chapter 44 Configuring IPv6 MLD Snooping
How to Configure IPv6 MLD Snooping

Enabling or Disabling MLD Snooping

By default, IPv6 MLD snooping is globally disabled on the switch and enabled on all VLANs. When
MLD snooping is globally disabled, it is also disabled on all VLANs. When you globally enable MLD
snooping, the VLAN configuration overrides the global configuration. That i s, MLD snooping is enabled
only on VLAN interfaces in the default state (enabled).
You can enable and disable MLD snooping on a per-VLAN basis or for a range of VLANs, but if you
globally disable MLD snooping, it is disabled in all VLANs. If global snooping is enabled, you can
enable or disable VLAN snooping.

Multicast Router Port

Although MLD snooping learns about router ports through MLD queries and PIMv6 queries, you can
also use the command-line interface (CLI) to add a multicast router port to a VLAN. To add a multicast
router port (add a static connection to a multicast router), use the ipv6 mld snooping vlan mrouter
global configuration command on the switch.

MLD Immediate Leave

When you enable MLDv1 Immediate Leave, the switch immediately removes a port from a multicast
group when it detects an MLD Done message on that port. You should only use the Immed iate-Leave
feature when there is a single receiver present on every port in the VLAN. When there are multiple
clients for a multicast group on the same port, you shoul d not enable Immediate-Leave in a VLAN.

MLD Snooping Queries

When Immediate Leave is not enabled and a port receives an MLD Done message, the switch generates
MASQs on the port and sends them to the IPv6 multicast address for which the Done message was sent.
You can optionally configure the number of MASQs that are sent and the length of time the switch waits
for a response before deleting the port from the multicast group.
How to Configure IPv6 MLD Snooping
Note When the IPv6 multicast router is a Catalyst 6500 switch and you are using extended VLANs (in the
range 1006 to 4096), IPv6 MLD snooping must be enabled on the extended VLAN on the Catalyst 6500
switch in order for the switch to receive queries on the VLAN. For normal -range VLANs (1 to 1005), it
is not necessary to enable IPv6 MLD snooping on the VLAN on the C atalyst 6500 switch.

Enabling or Disabling MLD Snooping

Command Purpose
Step 1 configure terminal Enters global configuration mode.
Step 2 ipv6 mld snooping Globally enables ML D snooping on the switch.