31.3.3 Notes on IPv6 Multicast Forwarding Function

Note the following points when using the IPv6 multicast forwarding functionality.

• MTU length of the interface used in IPv6 multicasting

  If the MTU length of the forwarding destination interface is shorter than that of the receiving interface, IPv6 multicast packets whose MTU length is longer than the forwarding destination interface cannot be forwarded properly. Make sure that the same MTU length value is used for all interfaces that are used in IPv6 multicasting.