62
As shown in
, Switch A works as an MLD snooping proxy. As a host from the perspective of the
querier Router A, Switch A represents its attached hosts to send their membership reports and done
messages to Router A.
describes how an MLD snooping proxy processes MLD messages.
Table 7
MLD message processing on an MLD snooping proxy
MLD message Actions
General query
When receiving an MLD general query, the proxy forwards it to all ports but the receiving
port. In addition, the proxy generates a report according to the group memberships that it
maintains and sends the report out of all router ports.
Multicast-addres
s-specific query
In response to the MLD group-specific query for a certain IPv6 multicast group, the proxy
sends the report to the group out of all router ports if the forwarding entry for the group still
contains a member port.
Report
When receiving a report for an IPv6 multicast group, the proxy looks up the multicast
forwarding table for the entry for the multicast group.
•
If a forwarding entry matches the IPv6 multicast group, and contains the receiving port
as a dynamic member port, the proxy restarts the aging timer for the port.
•
If a forwarding entry matches the IPv6 multicast group but does not contain the receiving
port, the proxy adds the port to the forwarding entry as a dynamic member port and
starts an aging timer for the port.
•
If no forwarding entry matches the IPv6 multicast group, the proxy creates a forwarding
entry for the group, adds the receiving port to the forwarding entry as a dynamic
member port, and starts an aging timer for the port.
Then, the switch sends the report to the group out of all router ports.
Done
In response to a done message for an IPv6 multicast group, the proxy sends a
multicast-address-specific query for the group out of the receiving port. After making sure
that no member port is contained in the forwarding entry for the IPv6 multicast group, the
proxy sends a done message for the group out of all router ports.
Protocols and standards
RFC 4541,
Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener
Discovery (MLD) Snooping Switches
MLD snooping configuration task list
Task
Remarks
Configuring basic MLD
snooping functions
Required
Specifying the version of MLD snooping
Optional
Configuring IPv6 static multicast MAC address entries
Optional
Configuring MLD snooping port
functions
Configuring aging timers for dynamic ports
Optional
Optional
Configuring a port as a simulated member host
Optional
Enabling fast-leave processing
Optional