Posts

How Much Air-Time Do Beacons Actually Burn?

Image
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 actual user d

5GHz Unlicensed WiFi Channels in the UK - White Paper

(Note: this white paper has been superseded with this new updated version ) I put together a few articles a few months ago talking about how the unlicensed 5GHz band is used for WiFi here in the UK. I thought it might be a good idea to consolidate all of the information that I found in to one place, so that people researching the topic could find and digest it more easily. Therefore I put together a white paper about how 5GHz is used for WiFi here in the UK. You can download it from here. There will no doubt be errors, omissions and other facts that folks would like to suggest. So, please feel free to drop me a note and I'll update this document from time to time to improve the quality of information that it contains. Nigel. Download the document from the following sources: Scribd Google Docs

802.11ad - Just for Home Cinema...Right?

Image
One of the things I love about Twitter is that once in a while you stumble across something that completely shifts your view of the world. I spotted this little nugget (posted by  @wifichef ) a couple of days ago, which made me significantly re-assess my view of the application of 802.11ad technology: " A deeper dive in to High Capacity WLANs:  http://t.co/L6kcx5oMI9 " Expecting another deep dive in to 802.11n high density WLANs (...small cell sizes, using 5GHz, band steering, disabling lower speeds etc.) I clicked through the link to see if I could find any new information. However, I was completely surprised to find myself looking at a  whitepaper  discussing the merits of 802.11ad! In fact, it actually highlighted the disadvantages of a traditional 'legacy' WiFi network - this had me hooked :) I must admit that I had dismissed 802.11ad (which uses the 60GHz band) as a niche technology that I'd probably hardly ever see in the Enterprise environments that