Sniff Wi-Fi

Wi-Fi is a technology used around the world and we, as Americans, respect all cultures and creeds.  That said, occasionally we like to celebrate ourselves (NSFW, as if the title didn't make it obvious): Unfortunately, America has been behind the times in Wi-Fi.  No longer!  We now have motherf*#king 2.4 GHz channels 12 and 13. This blog has a rigid rule to avoid politics, so I'll phrase this as apolitically as I possibly can: from January 20, 2009 to January 19, 2016, America's wireless authority -- the Federal Communications Commission (FCC) -- repeatedly authored rules that damaged Wi-Fi.  In 2010 the FCC banned Wi-Fi on channels 120 through 128, in 2014 the FCC messed up channels 52 through 144 by requiring additional dynamic frequency selection (DFS) scanning and in 2016 the FCC declined a proposal by satellite phone provider Globalstar to allow 2.4 GHz channels 12 and 13 to be used for "terrestrial, low power services" (TLPS), which just so happen t...

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 th...

There are times in life when I feel like I've been misunderstood, and I would like to just wish away the communication gap.  Unfortunately, there is no Wi-Fi Jambi, so instead I am going to use this short blog post to try to smooth things over with Jussi Kiviniemi, SVP of Ekahau. For those who are unfamiliar, Ekahau is site survey software .  You can do predictive surveying (sometimes called "planning") with it and you can do live surveying (the "walking survey") with it.  Either way, the result is a nice looking "heat map" showing Wi-Fi coverage over your floorplans, like so: Jussi Kiviniemi is the public face of Ekahau.  He's a Finnish guy and he goes to Wi-Fi conferences, hosts events, is active on Twitter , etc. There are days when I think that Jussi doesn't like me.  And being the rugged, pro-American American that I am, I take responsibility for things that happen to me. The root of Jussi's occasional distaste for m...

Recommending the exact opposite of what every enterprise Wi-Fi infrastructure vendor recommends can be awkward.  As awkward as the first meeting between Hank Kingsley (Jeffrey Tambor) and the Wu-Tang Clan?  (WARNING: extremely NSFW) Maybe not that awkward.   But while Hank had trouble relating to Wu-Tang member Ghostface Killah, Wi-Fi folks can avoid trouble by being aware of an increasingly common problem, the Ghost Frame Killah. Ghosts, as we all are well aware, are apparitions that can have a detrimental effect on buildings built on Indian burial grounds, while remaining unseen to our earthly eyes.  If you have Ghosts, you may need to call a Ghost Bouncer to solve the problem. Ghost Frames, on the other hand, are Wi-Fi frames ("packets") that can have a detrimental effect on Wi-Fi networks, while remaining unseen to our earthly Wi-Fi sniffing tools.  The solution to Ghost Frames is a simple one, but one that requires Wi-Fi folks to do th...

Far be it from me to hate on a Wi-Fi vendor... ...but seeing Cisco's Wi-Fi recommendations for iPhones (and other Apple iOS devices) has led me to wonder whether The Cisco (Kid) is a Friend of Mine. Cisco released a Best Practices doc for supporting iPhones, iPads, et al. back in November.  For whatever reason I missed it back then.  I'm bringing it up now because Keith Parsons had something about it on his Twitter feed and Ekahau has a webinar coming up on designing a Wi-Fi network for iOS devices.   I am happy that Cisco is bringing up the topic of device-centric Wi-Fi design.  Wi-Fi is (or, at least, should be) all about the end user, and device-centric design implicitly acknowledges this. I am less happy at several of Cisco's actual recommendations.  They seem to have fallen into the trap of believing (or, more perhaps more accurately, leading) the Latest Trendy Wi-Fi Disease, throughputitis .   Throughputitis , as you all ...

Yo, man.  There's a lot of Wi-Fi installers out there flakin' and perpetratin', but scared to kick reality... So what you want Wi-Fi engineers and admins to do? Assess Yourself!     To which you might respond, "Duh!" Any networking or Wi-Fi person worth a lick knows that a network should be assessed before (and, in many cases, after) deployment.  What is far, far, far less well known is HOW to assess a Wi-Fi installation.   Properly assessing a Wi-Fi installation involves two parts: assessing configuration settings and assessing the physical location of access points (APs) and antennas.  And if you don't assess both, you'll be  making a sucker and you equal .  While rolling through the streets of Searcy, AR in my main man  GT Hill 's 1984 Ferrari convertible, I was given some wise insight.  Not, "I only buy things that make money back," a former favorite quote of GT's prior to the purchase of said Ferrari.  Instead, ...

When using Wi-Fi spectrum analyzers, it's good to remember an old Russian proverb: Trust, but verify. Recently, I was doing some work for a company that needs BYOD Wi-Fi at several office spaces in multi-tenant buildings (insert: lame excuse for not blogging more) and we ran into what seemed to be an interference problem. Why did I think it was an interference problem? I had already completed the following checklist: 1. Cisco AP transmit power set to level 2 or 3 (that's 20 dBm to 17 dBm if you're using 3600/3700/3800 APs)? Check. 2. RRM channels 2, 3, 4, 5, 7, 8, 9 and 10 disabled? Check. 3. Excess 2.4 GHz radios disabled based on a survey done using an iPhone 4s? (What can I say? I'm a big softy for users who over-extend the life of their smartphones. They're the real MVPs of climate change.) Check. 4. OmniPeek captures, done from potential "neighbor" trouble areas, to look for channels occupied by large amounts of Retry frames? ...