IGMP Snooping: What is It and How Does it Help?

When dealing with network traffic, especially those dealing with multicast traffic, understanding the concept of IGMP Snooping can be a lifesaver.

This article will cover everything you need to know about IGMP Snooping, from what it is to how it works and why you should consider implementing this into your network. Let’s get started!

What is IGMP Snooping?

Internet Group Management Protocol (IGMP) snooping is a process that helps optimize the performance of L2 multicast networks by limiting bandwidth consumption and reducing the processing load on end systems.

It functions as an Ethernet layer 2 switch feature that listens for Internet Protocol (IP) multicast traffic and can interact with the IP multicast routing protocol.

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How Does IGMP Snooping Work?

IGMP snooping works by controlling which port on a switch forwards IP multicast traffic to prevent unnecessary flooding of packets out of all ports.

By default, Layer 2 switches broadcast all packets out of all ports, so it’s necessary to send only those packets that should be received by connected hosts.

In order for this process to happen, the switch must understand which ports have devices that are interested in receiving specific types of multicast traffic.

When a host wants to join or leave a multicast group, it sends an IGMP membership report to the switch. The switch then stores this information in a snooping table for later use.

Whenever the multicast traffic comes in, the switch can then forward that packet out only to those ports that have registered hosts that are interested in receiving it.

Benefits of Implementing IGMP Snooping

IGMP Snooping is a powerful tool that provides two main benefits:

Network performance optimization

One of the primary benefits of using IGMP snooping is improved network performance and reduced bandwidth consumption.

Since only relevant traffic is being sent out to connected devices, there isn’t as much unnecessary data clogging up your network.

This helps speed up communication between devices on your network as well as make more efficient use of your available internet bandwidth.

Network Security

In addition to improving network performance, IGMP snooping can also help improve security on your network.

Limiting the amount of IP multicast traffic being sent out, helps reduce the risk of malicious actors attempting to exploit any vulnerabilities in these types of networks.

It also reduces the chances of broadcast storms occurring, which can take down an entire network if left unchecked.

IGMP Snooping On or Off

IGMP Snooping is a network feature that can be either enabled or disabled on network switches.

When IGMP Snooping is turned ON, the switch monitors the Internet Group Management Protocol (IGMP) messages exchanged between multicast routers and hosts.

This intelligent monitoring enables the switch to determine which ports have active multicast group members.

Consequently, the switch forwards multicast traffic only to the specific ports where group members reside, optimizing bandwidth usage and reducing unnecessary multicast flooding.

By doing so, IGMP Snooping helps to improve network efficiency and reduce potential network congestion.

On the other hand, if IGMP Snooping is turned OFF, the switch treats all ports as if they have active multicast group members.

This can result in the flooding of multicast traffic to all ports, which may lead to wasted bandwidth and increase the likelihood of network bottlenecks.

IGMP Snooping Unifi

IGMP Snooping is a crucial feature in the UniFi networking ecosystem. UniFi, developed by Ubiquiti Networks, offers a range of products for managing and optimizing network performance, and IGMP Snooping is one of its key components.

With IGMP Snooping enabled on UniFi switches, the network becomes more intelligent in handling multicast traffic. The feature allows switches to listen to Internet Group Management Protocol (IGMP) messages exchanged between multicast routers and hosts.

By doing so, the switches can dynamically learn the multicast group memberships of connected devices.

IGMP Snooping in the UniFi environment is particularly beneficial in scenarios where bandwidth-intensive applications such as video streaming or online gaming are prevalent. By optimizing multicast traffic delivery, UniFi networks can ensure a smoother and more reliable user experience.


Overall, implementing IGMP Snooping is a great way to optimize the performance and security of your L2 multicast networks.

Not only does it prevent unnecessary flooding of packets out of all ports, but it also helps make more efficient use of available internet bandwidth as well as reducing the chances of broadcast storms occurring.

If you’re looking for an easy and effective way to manage your multicast traffic, then IGMP Snooping is definitely worth considering.

Ultimately, with careful planning and proper implementation, IGMP Snooping can be a great tool that helps keep your network running smoothly and securely.

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