Protocols And Standards - HP FlexNetwork 7500 Series Configuration Manual

•
If a match is found but the receiving port is not an outgoing interface in the forwarding entry, the
Layer 2 device discards the MLD done message.
•
If a match is found and the receiving port is not the only outgoing interface in the forwarding
entry, the Layer 2 device performs the following actions:
Discards the MLD done message.
Sends an MLD multicast-address-specific query to identify whether the group has active
listeners attached to the receiving port.
Sets the aging timer for the receiving port to twice the MLD last listener query interval.
•
If a match is found and the receiving port is the only outgoing interface in the forwarding entry,
the Layer 2 device performs the following actions:
Forwards the MLD done message to all router ports in the VLAN.
Sends an MLD multicast-address-specific query to identify whether the group has active
listeners attached to the receiving port.
Sets the aging timer for the receiving port to twice the MLD last listener query interval.
After receiving the MLD done message on a port, the MLD querier resolves the IPv6 multicast group
address in the message. Then, it sends an MLD multicast-address-specific query to the IPv6
multicast group through the receiving port.
After receiving the MLD multicast-address-specific query, the Layer 2 device forwards the query
through all its router ports in the VLAN and all member ports of the IPv6 multicast group. Then, it
waits for the responding MLD report from the directly connected hosts. For the dynamic member port
that received the done message, the Layer 2 device also performs one of the following actions:
•
If the port receives an MLD report before the aging timer expires, the Layer 2 device resets the
aging timer for the port.
•
If the port does not receive any MLD report messages when the aging timer expires, the Layer
2 device removes the port from the forwarding entry for the IPv6 multicast group.

Protocols and standards

RFC 4541, Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener
Discovery (MLD) Snooping Switches
General configuration restrictions and guidelines
When you configure MLD snooping, follow these restrictions and guidelines:
•
For a VLAN configured with MLD snooping, if you change the VPN instance bound to the VLAN
interface, Layer 2 multicast traffic for the VLAN is interrupted. In this case, you must execute the
reset mld-snooping group command so that new MLD snooping forwarding entries can be
created.
•
For MLD reports received from secondary VLANs, the relevant MLD snooping forwarding
entries are maintained by the primary VLAN. Therefore, you need to configure MLD snooping
only for the primary VLAN. The configuration made in secondary VLANs will not take effect. For
more information about primary VLANs and secondary VLANs, see Layer 2—LAN Switching
Configuration Guide.
•
The MLD snooping configurations made on Layer 2 aggregate interfaces do not interfere with
the configurations made on member ports. In addition, the configurations made on Layer 2
aggregate interfaces do not take part in aggregation calculations. The configuration made on a
member port of the aggregate group takes effect after the port leaves the aggregate group.
230