It can be frustrating fighting multicast flooding issues because they are largely invisible and can cause widespread issues. The intent of this guide is to give you a few tips on how to make implementing a basic IGMP configuration as simple as possible. I want to preface this guide by letting you know that I am just showing the basics here that have showed tremendous results in less than ideal situations.


DISCLAIMER:
This is not meant to be a complete, flawless, in-depth guide, just sharing the basics that might help in a time crunch.

Here is the simple explanation of what you are looking to do.
On your Layer 3 interface of your VLAN (SVI), you are going to enable IGMP. On Layer 2, you will enable IGMP snooping.

Some important things to keep in mind:

1. If your switches do not have a Layer 3 interface, you need to specify the existing IGMP querier after enabling snooping.
2. Aruba CX switches use IGMPv3 by default. Unless your application requires SSM (Source-Specific Multicast), I recommend sticking with IGMPv2 to avoid possible issues and unnecessary complexity.

Let’s get started

1. SVI configuration
   switch# conf t
   switch(config)#
   switch(config)# int vlan 200 <—–(Select the layer 3 interface of your VLAN)
   switch(config-if-vlan)# ip igmp enable
   switch(config-if-vlan)# ip igmp version 2
   
   
2. VLAN configuration
   
   switch(config-if-vlan)# vlan 200 <—– (Select your VLAN)
   switch(config-vlan-200)# ip igmp snooping enable
   switch(config-vlan-200)# ip igmp snooping version 2
   
   
3. Show commands
   
   I’m not showing the full output of all commands, but here are some helpful ones for troubleshooting.
   
   
   switch(config)# show run int vlan 200
   interface vlan200
   ip address 10.0.0.1/24
   ip igmp enable
   ip igmp version 2
   exit
   
   
   switch(config-if)# show ip igmp
   
   VRF Name : default
   Interface : vlan200
   IGMP Configured Version : 2
   IGMP Operating Version : 2
   Querier State : Querier
   Querier IP [this switch] : 10.0.0.1 <—–(If everything is working correctly you should see the Querier)
   Querier Uptime : 7m 3s
   Querier Expiration Time : 0m 19s
   IGMP Snoop Enabled on VLAN : True
   
   switch(config-if-vlan)# show ip igmp snooping counters
   IGMP Snooping VLAN Counters
   
   Rx Counters :
   V1 All Hosts Queries 0
   V2 All Hosts Queries 0
   V3 All Hosts Queries 0
   V2 Group Specific Queries 0
   V3 Group Specific Queries 0
   Group And Source Specific Queries 0
   V1 Member Reports 0
   V2 Member Reports 0
   V3 Member Reports 0
   V2 Member Leaves 0
   
   
   switch(config)# show ip igmp snooping statistics
   
   IGMP Snooping Protocol Info
   
   Total VLANs with IGMP enabled : 1
   Current count of multicast groups joined : 0
   
   
   
   Multicast doesn’t have to be mysterious. This guide is meant to help when you’re dealing with multicast issues under real world pressure. I’m not an expert, and there’s always more to learn, but even a simple IGMP configuration can have a huge impact. Start simple!