In Search of an Accurate Site Survey

This week's big Wi-Fi news was Ekahau's introduction of the Sidekick, an easy-to-carry, laptop battery-conserving device designed to make Wi-Fi site surveying more elegant.  Unfortunately, it appears to do more to exacerbate Wi-Fi problems than to solve them.

What is the number one problem in enterprise Wi-Fi?

It surely can't be security.  Security is a hot topic, but Wi-Fi security isn't really a problem anymore.  Even security problems that Wi-Fi gets blamed on -- Pineapple hijacking, Wi-Phishing, man-in-the-middle -- either aren't problems for modern devices & applications, or are problems that extend beyond Wi-Fi.

Maybe it's user density?  Or supporting a variety of devices?  Maybe it's connection issues; when moving or when the device is idle for too long?

Whatever the answer, chances are it comes down to one overarching issue: different Wi-Fi devices behave differently.  Capacity testing gets done using laptops, then smartphones cause the Wi-Fi to go bad with fewer connected devices.  Connections with Windows laptops work great, but Chromebooks take forever to get an IP address.  And so on and so forth.

I would go even deeper.  I would say that the intrinsic problem is that Wi-Fi professionals don't care enough about Wi-Fi users.  Why else would someone capacity test using a laptop, if it is known that Wi-Fi users will be on smartphones?  Why else would someone use a Windows laptop to survey a classroom that will be full of Chromebooks or iPads?  Either the Wi-Fi guy (or gal) is unaware of the fact that different Wi-Fi devices behave differently, or they are what I said they are; people who don't care enough about Wi-Fi users.

To my eyes, Ekahau's Sidekick only exacerbates the problem.  It's a device that behaves differently from a Wi-Fi user's device, yet it's supposed to be used for surveying.  What's more, Ekahau promotes the Sidekick for *faster* surveying.  Faster surveying surely means faster walking, which means getting further astray from the Wi-Fi user's experience.  Students in classrooms and workers in offices don't need to know what RSSI (received signal strength indicator) a Sidekick saw when the Wi-Fi guy was walking really fast through an empty room.  They need their smartphones, tablets and laptops to get connected, stay connected and have adequate performance when running production applications.  Period.  Exclamation point.

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I want this blog to be helpful.

Is it helpful to say, "the Sidekick is counter-productive"?  Sure, in a way.  Just as it's helpful to say, "asking that waitress for her phone number isn't going to make your wife happy."  Hating is often helpful.  But let's go beyond that.  Let's also tell our friend, "marriage requires patience, so even though this waitress may seem like a more fun version of your wife, in the long run you'll be better off if you stay faithful."  In addition to hating, let's add a viable solution.

Here, then, is what I would recommend for a walking survey:

1. Get a production Wi-Fi device.  (If you have to support a number of device types, then choose a device that will provide an adequate baseline.  For a recent survey, I used an old iPhone that has an 802.11ac, non-MIMO Wi-Fi radio.)

2. Get a floorplan that you can write on.  (I get or make a PDF floorplan, then open it on a large screen iPad Pro using iAnnotate PDF.  I write using an Apple Pencil.)

3. Choose several "surveying" locations on the floorplan.  (Here's where an experienced Wi-Fi professional can be helpful.  He/she should be able to choose locations that will validate the overall goal of the install: to have consistent, stable Wi-Fi anywhere for any device running any production application.)

4. "Survey" at each location.  (Connect at the location.  Check the RSSI at the location.  Check the RSSI of nearby APs at the location [for interference and redundancy].  Turn the device from portrait mode to landscape mode, at the location.  Hold the device in your hand, then lay it on the table [at the location].  Maybe even do a throughput test at the location, if you are working for someone who puts stock in throughput tests.  Again, this is a step where having an experienced Wi-Fi professional on site can help.)

5. Write down the results of your "survey".  (Definitely RSSI and notes about nearby AP redundancy and/or interference.  Additional notes may be added.  This is yet another step where being an experienced Wi-Fi professional helps.)

6. Repeat steps 5 and 6 at one of the other surveying locations.  (Lather, rinse, repeat.  Lather, rinse, repeat.)

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You may find that this blog comes off negatively towards Ekahau's new product, the Sidekick, and towards Ekahau in general.  I'll respond to that straw man by saying the same thing I said in my last blog (two months ago!  Sheesh, I've got to do more blogging): Ekahau is a great DOCUMENTATION tool for Wi-Fi surveys and it looks to me like the Sidekick will make Wi-Fi survey documentation faster and simpler.

The recommended survey steps I listed above are for surveying, only.  Meaning, for getting a gauge of real world Wi-Fi coverage, access and stability.  I said nothing about documentation.

Use Ekahau Site Survey and an Ekahau Sidekick for documentation.  Or use what I use from time to time: Netscout AirMagnet Survey and a couple of Proxim 8494 USB adapters for documentation.  Just make sure you avoid those things if you are in search of an accurate Wi-Fi site survey.

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Twitter: @Ben_SniffWiFi

ben at sniffwifi dot com