How Much Air-Time Do Beacons Actually Burn?
It’s a well known rule of thumb when designing WiFi networks that you need to try to keep the number of SSIDs broadcast by your wireless network down to a ‘reasonable’ number. In this article, I take a look at how much of an issue SSIDs (and their beacons) are in consuming valuable wireless air-time. Generally, it’s recommended to keep the number of SSIDs below around 5 (ish). The reason for keeping the number of SSIDs to a minimum is that each SSID is advertised using a type of management frame called a ‘beacon’. Beacons are generally sent 10 times per second for each SSID on the wireless network. Therefore, if you have 10 SSIDs, they will each be advertised 10 times per second, giving us 100 beacons per second. Air-time is a finite resource – there is only so much data that can be transferred across the air over a period of one second. If a large chunk of air-time is being consumed by SSID beacons, then that doesn’t leave a whole lot of time remaining for actu...