Using Discovery Software, Illustrated (with iOS Airport Utility)

I wrote about using Discovery software, and then it dawned on me: many people prefer pictures.

Here, then, is how I use Discovery software when troubleshooting Wi-Fi, illustrated.

First, I figure out which device needs troubleshooting.  In this case, let's pretend it's one or more iPhones.

(That #nofilter picture was taken by me at about 4:50 a.m. on the morning of January 20, 2009.  It was COLD a.f. out there.)

Notice how my iPhone shows RSSI instead of signal bars.  

Once I know which device needs troubleshooting (and, PLEASE, do not skip that first step.  Troubleshooting without using the actual device that needs to use the Wi-Fi is a big waste of time that annoys users), then I need some Discovery software.

iOS: Airport Utility (Apple)
Mac OS X: Wireless Diagnostics (Apple), WiFi Explorer (Adrian Granados - $15)
Windows: Acrylic WiFi (Tarlogic), inSSIDer (Metageek - $20)
Android: WiFi Analyzer (farproc)
Chrome OS: NONE

I am troubleshooting an iPhone, so I need Apple's Airport Utility, which is available in the iOS App Store.  

(It's free.)

Once I've installed Airport Utility, then I need to enable the "Wi-Fi Scanner" function.  To my knowledge, this is the ONLY way to do Discovery using a non-jailbroken iOS device.

Go into your iPhone/iPod/iPad's Settings, then find AirPort Utility...

...then enable "Wi-Fi Scanner" at the bottom of the screen.

Once "Wi-Fi Scanner" is enabled, Airport Utility will be able to act as Discovery software.  

Now, go to the location that needs troubleshooting (and, honestly, in a lot of cases Discovery software is great for PREVENTION.  If you know that there's a place where Wi-Fi is going to be heavily used or is super important, you can do a scan using Discovery software BEFORE users start complaining) and record a Scan in AirPort Utility.

Start by opening the AirPort Utility app...

...then choose "Wi-Fi Scan"...'ll want to choose how long to scan for (or, for site surveys, you'll want to use a "Continuous" scan, which is the default)...

...and then after you tap "Scan" and wait for your scan to finish, you'll get an output that looks something like this:

In the lower-left corner of my scan, notice that little button that lets me export.  I recommend emailing yourself the scan output...

...which will be exported in *.csv form.

To view the scan results in a more accessible form, I like to copy-and-paste the results into a text file...

...find the text file and use Get Info... change the file type to *.csv.

(It is at this point that I should note that I AM NOT A COMPUTER GUY.  I fully believe you when you tell me that there are quicker, more efficient ways to save AirPort Utility scans to *.csv.  GREAT.  Please, by all means, post them in the comments.  But I do stuff MY WAY.  Think of me as one of those little old ladies who was still paying AT&T $3.95/month to rent a landline phone in 1994.  The only thing I care about doing efficiently is making your Wi-Fi work.)

*.csv files can be opened in any spreadsheet application.  I use Numbers for Mac OS X:

Once your AirPort Utility scan is opened in your spreadsheet application, you will need to filter it so that each BSS only shows once:

Et voilá, you have effectively used Discovery software to troubleshoot an enterprise Wi-Fi network.  

From the information culled from a Discovery scan, you can often make adjustments that will fix your Wi-Fi:  

-If you see more than one of your own APs (at -80 dBm RSSI or higher) using the same/overlapping channel(s), then you can override your controller's auto-RF settings and change your APs' channels.  
-If you see more than three APs using the 2.4 GHz frequency band, then you can, again, override your controller's auto-RF settings and disable one or more of your APs' 2.4 GHz radios.  
-If you see that 5 GHz coverage is lacking, then you can go back to your site survey/design report and try to find a place to install a new AP.  

As you might expect from a tool that costs zero dollars, Discovery software has limits.  For example, when controllers' auto-RF settings keep APs' transmit power at low levels, Discovery software will be unable to diagnose an over-deployment of APs.  

To fill in your troubleshooting gaps, I strongly advise Wi-Fi people to have a Network analyzer (which is what I used to call a "Protocol analyzer", but I was told today that I'm using an outdated term) and a Spectrum analyzer at their disposal as well.  I'll cover those two Wi-Fi troubleshooting tools, with illustrations, in future blog posts.

If you like my blog, you can support it by shopping through my Amazon link.  You can also donate Bitcoin to 1N8m1o9phSkFXpa9VUrMVHx4LJWfratseU or to my QR code:

Twitter: @Ben_SniffWiFi
ben at sniffwifi dot com


Popular posts from this blog

Spectrum Deception

What's New (and Missing) in the WiFi for iPhone 6

Free Sniffing in Windows! (Kind Of)