IGMP Snooping is a common advanced option available on most of the routers. In this Layman’s IGMP Snooping guide, we will go over what IGMP Snooping does, and when you might need to enable IGMP Snooping configuration.
What is IGMP Snooping
From the default router advanced settings tooltip on an Asus branded router:
When enabled, IGMP Snooping monitors IGMP communications among devices and optimizes wireless multicast traffic.
This definition does not really explain much. However, a simpler way to put it is that IGMP Snooping can be enabled so that your router acts as a mailman or gate for the multicast traffic.
When your network has plenty of multicast traffic, the performance for the entire network can take a hit because of excessive false flooding. IGMP Snooping optimizes that performance overhead. The Router decides which devices will receive the applicable multicast traffic to improve the overall network speed.
But if you have little multicast traffic to begin with, say your home based wireless network where you just use it for basic internet and gaming use. IGMP Snooping will not help with any of the wifi performance issue. It will in fact be wasted resources for your router to listen or monitor for nonexistent type of traffic on your wifi setup.
When to Enable IGMP Snooping for Home Use
For a home based network, you should enable it when you frequently use any kind of streaming or mirroring from your devices to stream to Apple TV or Chromecast. In some brand firmware such as Asus, enabling IGMP Snooping can fix some of the Apple TV Airplay mirroring issues.
One of the most commonly reported problem is that Apple TV’s streaming function does not work when you stream with Airplay mirroring from a device such as iphone, ipad, or mac connected with a 5 Ghz frequency. (However you can still use mirroring with a 2.4 Ghz frequency).
You should generally leave the IGMP Snooping option as disabled if you do not use mirroring functions or other type of multicast traffic. In this case, leaving IGMP Snooping as “enabled” has no advantage and can waste some of the processing power since your router will be constantly monitoring applicable multicast transmissions that simply do not exist on your network.