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INS_CWGE24MS2_REV–
10/05/16 PAGE 73
INSTALLATION AND OPERATION MANUAL
CWGE24MS2
TECH SUPPORT: 1.888.678.9427
removed from multicast group membership.
IGMP Querier
There is normally only one Querier per physical network. All multicast routers start up as a Querier
on each attached network. If a multicast router hears a Query message from a router with a lower
IP address, it MUST become a Non-Querier on that network. If a router has not heard a Query
message from another router for [Other Querier Present Interval], it resumes the role of Querier.
Routers periodically [Query Interval] send a General Query on each attached network for which
this router is the Querier, to solicit membership information. On startup, a router SHOULD send
[Startup Query Count] General Queries spaced closely together [Startup Query Interval] in order
to quickly and reliably determine membership information. A General Query is addressed to the
all-systems multicast group (224.0.0.1), has a Group Address field of 0, and has a Max Response
Time of [Query Response Interval].
Port IGMP Querier Mode
» Auto:
The Switch uses the port as an IGMP query port if the port receives IGMP query packets.
» Fixed:
The Switch always treats the port(s) as IGMP query port(s). This is for when connecting an IGMP
multicast server to the port(s). The Switch always forwards the client’s report/leave packets to the
port.
Normally, the port is connected to an IGMP server.
» Edge:
The Switch does not use the port as an IGMP query port. The IGMP query packets received by
this port will be dropped.
Normally, the port is connected to an IGMP client.
Note: The Switch will forward the IGMP join and leave packets to the query port.
Configurations:
Users can enable/disable the IGMP Snooping on the Switch. Users also can enable/disable the
IGMP Snooping on a specific VLAN. If the IGMP Snooping on the Switch is disabled, the IGMP
Snooping is disabled on all VLANs even some of the VLAN IGMP Snooping are enabled.