Protocols And Standards - H3C S3100 Series Operation Manual

Figure 3-3 Network diagram for MLD snooping proxying
As shown in Figure
the querier Router A, Switch A represents its attached hosts to send their membership reports and done
messages to Router A.
Table 3-2 describes how an MLD Snooping proxy processes MLD messages.
Table 3-2 MLD message processing on an MLD snooping proxy
MLD message
General query
Multicast-addres
s-specific query
Report
Done

Protocols and Standards

MLD snooping is documented in:
RFC 4541: Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener
Discovery (MLD) Snooping Switches
3-3, Switch A works as an MLD Snooping proxy. As a host from the perspective of
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 it
maintains and sends the report out all router ports.
In response to the MLD group-specific query for a certain IPv6 multicast group, the proxy
sends the report to the group out all router ports if the forwarding entry for the group still
contains a member port.
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 the forwarding entry is found with the
receiving port contained as a dynamic port in the outgoing port list, the proxy resets the
aging timer for the entry. If the forwarding entry is found but the outgoing port list does not
include the receiving port, the proxy adds the port to the outgoing port list as a dynamic
member port and starts an aging timer for it. If no forwarding entry is found, the proxy
creates the entry, adds the receiving port to the outgoing port list as a dynamic member port
and starts an aging timer for the port, and then, sends a report to the group out all router
ports.
In response to a done message for an IPv6 multicast group, the proxy sends a
multicast-address-specific query for the group out 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 all router ports.
Actions
3-6