Processing Of Ipv6 Multicast Protocol Messages - HP 4800G Series Configuration Manual

If the forwarding table entry does not exist or if the outgoing port list does not contain the port, the
switch discards the MLD done message instead of forwarding it to any port.
If the forwarding table entry exists and the outgoing port list contains the port, the switch forwards
the MLD done message to all router ports in the native VLAN. Because the switch does not know
whether any other hosts attached to the port are still listening to that IPv6 multicast group address,
the switch does not immediately remove the port from the outgoing port list of the forwarding table
entry for that group; instead, it resets the aging timer for the port.
Upon receiving an MLD done message from a host, the MLD querier resolves the IPv6 multicast group
address in the message and sends an MLD multicast-address-specific query to that IPv6 multicast
group address through the port that received the MLD done message. Upon receiving the MLD
multicast-address-specific query, the switch forwards it through all the router ports in the VLAN and all
member ports for that IPv6 multicast group, and performs the following to the receiving port:
If any MLD report in response to the MLD multicast-address-specific query is received on the port
(suppose it is a dynamic member port) before its aging timer expires, this means that some host
attached to the port is receiving or expecting to receive IPv6 multicast data for that IPv6 multicast
group. The switch resets the aging timer for the port.
If no MLD report in response to the MLD multicast-address-specific query is received on the port
before its aging timer expires, this means that no hosts attached to the port are still listening to that
IPv6 multicast group address. The switch removes the port from the outgoing port list of the
forwarding table entry for that IPv6 multicast group when the aging timer expires.

Processing of IPv6 Multicast Protocol Messages

With Layer 3 multicast routing enabled, an MLD Snooping switch processes IPv6 multicast protocol
messages differently under different conditions, specifically as follows:
1) If only MLD is enabled, or both MLD and IPv6 PIM are enabled on the switch, the switch handles
IPv6 multicast protocol messages in the normal way.
2) In only IPv6 PIM is enabled on the switch:
The switch broadcasts MLD messages as unknown messages in the VLAN.
Upon receiving an IPv6 PIM hello message, the switch will maintain the corresponding dynamic
router port.
3) When MLD is disabled on the switch:
If IPv6 PIM is disabled, the switch deletes all its dynamic member ports and dynamic router ports.
If IPv6 PIM is enabled, the switch deletes only its dynamic member ports without deleting its
dynamic router ports.
On a switch with Layer-3 IPv6 multicast routing enabled, use the display mld group port-info
command to view Layer-2 port information.
For details about the display mld group port-info command, refer to MLD Commands in the IP
Multicast Volume.
4) When IPv6 PIM is disabled on the switch:
If MLD is disabled, the switch deletes all its dynamic router ports.
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