Restrictions and guidelines: IPv6 PIM snooping configuration
As a best practice, do not configure IPv6 PIM snooping for secondary VLANs because IPv6 PIM snooping does not take effect on secondary VLANs. For more information about secondary VLANs, see Layer 2—LAN Switching Configuration Guide.
Make sure the maximum size of an IPv6 PIM join or prune message is smaller than the path MTU of devices connected to IPv6 PIM snooping devices. Otherwise, fragmented IPv6 PIM join or prune messages prevent IPv6 PIM snooping from correctly forwarding IPv6 multicast data. For more information about setting the maximum size of a join or prune message, see "Configuring IPv6 PIM."
IPv6 PIM snooping is supported only for IPv6 PIM-SM and IPv6 PIM-SSM. As a best practice, do not configure IPv6 PIM snooping in the IPv6 PIM-DM or IPv6 BIDIR-PIM network. For more information about IPv6 PIM, see "Configuring IPv6 PIM."
After you enable IPv6 PIM snooping for a VLAN, IPv6 PIM snooping takes effect only on ports that belong to the VLAN.