Wireless Controllers and Roaming: What You Need to Know
It has become an undeniable reality that Wi-Fi access is a requisite part of everyday life. In order to satisfy our ever-increasing appetite for connectivity, wireless networks will continue to grow. Extending a Wi-Fi network for greater coverage can be as simple as adding another access point (AP). However, you may find that this has an adverse impact on network performance with client devices that do not roam well from one AP to the next.
With any discussion of roaming, it’s important to understand that the decision to roam is determined by the client device. Wi-Fi was originally conceived with the idea that there would be very few APs, so client devices were designed to hang on to an AP as long as possible. This means that even if a client can talk to an AP with better signal quality, it may stay attached to another AP.
Roaming in a Wi-Fi network occurs when the client device decides to detach from one AP and reattach to a different AP. You might think that if a client “sees” an AP with a stronger signal or better signal quality, it would initiate a roam and try to attach to the AP with the best network link. Unfortunately, this isn’t how roaming works.
Although a few standards have been proposed and even adopted to help roaming, most of these standards are not widely implemented in APs or client devices. Most device manufacturers try to tailor their drivers to get the best user experience from a device and tend to keep their roaming algorithms proprietary.
Standard Wi-Fi Roaming
Let’s look at how a typical device roams. When a device attempts to connect to a Wi-Fi network, it will first search for APs. When it finds an AP to which it can authenticate, it will connect and participate on the network. As the client device moves around and away from the connected AP, the signal level and quality will degrade.