Multiple Potential Igmp Queriers; Example - Allied Telesis AR400 Series How To Configure

Multiple potential IGMP queriers

To find out more about IGMP, we next investigate what happens when more than one router
or switch has an IGMP configuration.
RFC 2236, Internet Group Management Protocol, Version 2,
should have only one IGMP Querier. You may configure IGMP on more than router or
switch, perhaps for redundancy, but the routers and switches have a pseudo election and the
device with the lower IP becomes the operating IGMP Querier. This example describes a
network with two potential Queriers.

Example

The network for this example uses the same loop as for
shown in the following figure.
Both switch 1 and switch 2 are configured with IGMP, making both of them potential
Queriers. Switch 3, by default configuration, is an IGMP Snooper.
Page 15 | AlliedWare™ OS How To Note: IGMP
Rapier 24i
Switch 2:
Elected Querier
port 2
Client 1
Multicast Server
port 1
AT-8948
port 50
(blocked by STP)
port 26
port 25
Multiple potential IGMP queriers > Example
says that each Layer 2 network
"IGMP snooping" on page 9
Switch 1:
Potential Querier
port 49
port 26
Rapier 24i
port 25
port 3
Client 2
and is
Switch 3:
Snooper
igmp-querier.eps