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These querier addresses can be anything you want really. It is not any actual ip address. What is it then? It is used as part of an election process. There can only be one querier active in a network. If multiple queriers are configured then an election process will begin. Who will be elected the active querier? The switch that has the lowest ip address value configured, in the querier ip field.
So, it is not a good idea to set the querier ip to the same as the switch. It should instead be setup up as an election model. What I would do, is set querier address 1.1.1.1 on the switch I want to be igmp querier primarily. The others I would set 2.2.2.2, 3.3.3.3, etc. As a hierarchical system: if the current querier goes down then the switch with the next lowest querier ip value would take over as querier.
This is important because you probably want your core/distribution switch to be the main querier.
As far as I know, the best practice is to use the IP address of the appropriate switch virtual interface as the IGMP Querier Address. If ever the switch does not have a switch virtual interface, you can use an unused IP address within the same subnet as the target VLAN.
Let me share this forum thread and it might help as reference.
The switch virtual interface is the IP Address you have assigned on a specific VLAN. This is best described if you have configured VLAN Routing on the switch. In order to route between VLANs, VLAN interfaces must have IP addresses. For example: VLAN 10 has a network IP Address of 192.168.10.0. You can assign an IP Address to VLAN 10 such as 192.168.10.1 or 192.168.10.254.
These querier addresses can be anything you want really. It is not any actual ip address. What is it then? It is used as part of an election process. There can only be one querier active in a network. If multiple queriers are configured then an election process will begin. Who will be elected the active querier? The switch that has the lowest ip address value configured, in the querier ip field.
So, it is not a good idea to set the querier ip to the same as the switch. It should instead be setup up as an election model. What I would do, is set querier address 1.1.1.1 on the switch I want to be igmp querier primarily. The others I would set 2.2.2.2, 3.3.3.3, etc. As a hierarchical system: if the current querier goes down then the switch with the next lowest querier ip value would take over as querier.
This is important because you probably want your core/distribution switch to be the main querier.
Notice for your VLAN 10, the Querier VLAN Address is 0.0.0.0. The reason for this is because you can configure a querier two ways: 1. Set a "global" querier address for all VLANs on that switch, which is what you did. 2. Set a unique querier address for each individual VLAN. That can be useful in certain scenarios where you might want switch A to be the querier for VLAN x and switch B to be querier for vlan y.
Most people would probably be fine with the first option, as you have done as well.
Don't forget that you still need to configure IGMP snooping as well, on the switch(es).
I would set it up one of two ways: per VLAN or global.
Global Enable IGMP snooping. Enable IGMP snooping on your ports under the IGMP interface configuration. Enable multicast router mode on the ports that uplinks to the other switches. Enable IGMP Querier Set a global Querier IP address (1.1.1.1 and next switch 2.2.2.2, etc.)
Per VLAN Enable IGMP snooping. Enable IGMP snooping on your VLANs under the IGMP VLAN configuration. Enable multicast router mode on the ports that uplinks to the other switches. Enable IGMP Querier Leave the global address at 0.0.0.0. Set instead a Querier IP address per VLAN under the Querier VLAN configuration (VLAN10=1.1.1.10 and VLAN15=1.1.1.15. Next switch VLAN10=2.2.2.10 and VLAN15=2.2.2.15, etc). Make sure “Querier Election Participation Mode” is enabled for each VLAN.
My preference is per VLAN because it gives more control. Say, in some VLANs I might not want snooping to occur, while in others I do. So, I am more comfortable with that config.
