Operation Manual – Multicast Protocol
H3C S3610&S5510 Series Ethernet Switches
Chapter 2 IGMP Snooping Configuration
2-4
I. When receiving a general query
The IGMP querier periodically sends IGMP general queries to all hosts and routers
(224.0.0.1) on the local subnet to find out whether active multicast group members
exist on the subnet.
Upon receiving an IGMP general query, the switch forwards it through all ports in the
VLAN except the receiving port and performs the following to the receiving port:
z
If the receiving port is a router port existing in its router port list, the switch resets
the aging timer of this router port.
z
If the receiving port is not a router port existing in its router port list, the switch adds
it into its router port list and sets an aging timer for this router port.
II. When receiving a membership report
A host sends an IGMP report to the multicast router in the following circumstances:
z
Upon receiving an IGMP query, a multicast group member host responds with an
IGMP report.
z
When intended to join a multicast group, a host sends an IGMP report to the
multicast router to announce that it is interested in the multicast information
addressed to that group.
Upon receiving an IGMP report, the switch forwards it through all the router ports in the
VLAN, resolves the address of the reported multicast group, and performs the
following:
z
If no forwarding table entry exists for the reported group, the switch creates an
entry, adds the port as member port to the outgoing port list, and starts a member
port aging timer for that port.
z
If a forwarding table entry exists for the reported group, but the port is not included
in the outgoing port list for that group, the switch adds the port as a member port to
the outgoing port list, and starts a member port aging timer for that port.
z
If a forwarding table entry exists for the reported group and the port is included in
the outgoing port list, which means that this port is already a member port, the
switch resets the member port aging timer for that port.
