Configuration Guide Configuring IGMP Snooping
Working Principle
A device running IGMP snooping can identify and handle the following types of IGMP packets:
Query Packets
An IGMP querier periodically send General Query packets. When the IGMP querier receives Leave packets, it sends
Group-Specific Query packets.
When the device running IGMP snooping receives the Query packets, it performs the following operations within the VLAN:
Forward the IGMP Query packets to all the ports (except the receiving port of these packets).
If the receiving port is a dynamic router port, reset the aging timer. If the timer expires, the port will no longer be used as
the dynamic router port.
If the receiving port is not a dynamic router port, use it as a dynamic router port and enable the aging timer. If the timer
expires, the port will no longer be used as the dynamic router port.
For general queries, reset the aging timer for all the dynamic member ports. If the timer expires, the port will no longer
be used as the dynamic member port for the general group. By default, the maximum response time carried by the
IGMP query packets is used as the timeout time of the aging timer. If ip igmp snooping query-max-response-time is
run, the time displayed is used as the timeout time of the aging timer.
For designated query packets, reset the aging timer for all the dynamic member ports of the designated profile. If the
timer expires, the port will no longer be used as the dynamic member port of the designated profile. By default, the
maximum response time carried by the IGMP query packets is used as the timeout time of the aging timer. If ip igmp
snooping query-max-response-time is run, the time displayed is used as the timeout time of the aging timer.
If dynamic router port learning is disabled, IGMP snooping will not learn the dynamic router port.
Report Packets
When a member host receives a query, it responds to the query with a Report packet. If a host requests to join a profile,
it will also send a report.
For the IGMPv3 Report packets, Ruijie products handle only the profile information but not the source information.
When the device running IGMP snooping receives the Report packets, it performs the following operations within the VLAN:
Forward the Report packets from all the router ports. After the ip igmp snooping suppression enable command is run
in one IGMP query cycle, only the first report received by each profile will be forwarded.
If the port on which Report packets are received is a dynamic member port, reset the aging timer. If the timer expires,
the port will no longer be used as the dynamic member port of the designated profile.
If the port on which Report packets are received is not a dynamic member port, use it as a dynamic member port and
enable the aging timer. If the timer expires, the port will no longer be used as the dynamic member port of the
designated profile.
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