Tag Archives: Wi-Fi Troubleshooting

Newsflash: All 5 GHz Clients Don’t Work on All 5 GHz Channels

OK- this really shouldn’t be a newsflash. But, if you’ve never had to deal with what I’m about to summarize, then it may well be a headline story. But first, a word from today’s musical guest- Genesis, fronted by the great Phil Collins:

Talk to me, you never talk to me.
Ooh, it seems that I can speak.
I can hear my voice shouting out.
But there’s no reply at all.

Look at me, you never look at me,
Ooh, I’ve been sitting, staring, seems so long.
But you’re looking through me
Like I wasn’t here at all.
No reply, there’s no reply at all.

Phil and the boys know well what happens when you assume that any 5 GHz client will work on any 5 GHz access point. Rumor has it that Genesis was troubleshooting a wireless installation at a mall in Duluth when they were inspired to write the super-hit “No Reply at All”, but that’s a story for another time.

I’m here to tell you of- and show you- an example of a 5 GHz client that just can’t (and therefore WON’T) talk to anything but a few 5 GHz channels. If it’s not obvious, there is high potential for the “the network sucks!”  factor here. If you don’t know what you’re doing, you can foolishly add more APs, tweak every setting there is to tweak, RMA one client device after another, and end up with an over-radiating nonfunctional heap of squadoosh, baby.

Trouble in Po Po Land

Once upon a time, there was an awesome dual-band Wi-Fi network that few could match. The APs were pretty, the signals were clean, and the installation crew was a bunch of snappy gents. Thousands upon thousands of client devices used this high-performing WLAN daily- every kind of laptop under the sun, all sorts of common mobile devices, and smartphones aplenty.

Then the police cars came.

The Long Arm of the Law wanted in on that Wi-Fi goodness. The idea was simple: police cars would pull into their very wireless well-covered parking area at the end of shift, and dashcam video would automatically download to network servers via that sweet, sweet Fi. A vendor was hired to equip the cars, the police technical staff got the lowdown from the network folks on how to configure the client devices, and everything seemed good.

Except it didn’t work.

About That Police Car Wireless Client Device

The cruisers in question are equipped with the Ubiquiti Bullet M5 radio. These have a handy form factor, and can be had for less than $100 (then obscenely marked up and resold as something special).  And look- they are 802.11a and 11n-capable!

M5-2

Should be no issues on that robust dual-band network, as long as signal is coming out of the 5 GHz radios in theAPs and the 5 GHz radio in the M5- yes? I can stand next to the police car with my iPhone and connect on 5 GHz, so the car should work too! But… the cars weren’t working at first, despite their 5 GHz output being verified with a number of tools.

Curse you, fickle Fi! What dark magic is afoot?

5 GHz is a Big Range of Channels. You Gotta Understand Those Channels.

So, this big world-class WLAN uses a lot of 5 GHz channels (36, 40, 44, 48, 52, 56, 60, 64, 149, 153, 157,  and 161). But take a look at that graphic again. The M5 operates in the range of 5170 to 5825 MHz, whatever that means. And did you catch the footnote?

DID YOU CATCH THE FOOTNOTE? (* Only 5725 – 5850 MHz is supported in the USA)

If you didn’t know any better, you might expect that the entire range of 802.11a and .11n is 5725-5850 MHz, and that all of the channels on the WLAN would fit in that range. This is American Wi-Fi, and that’s an American client device!

It just isn’t that simple. Looky here (5 GHz channels, Wikipedia):
5 chans

It turns out that the M5 only works in one small slice of the entire 5 GHz range that 802.11a/n/ac Wi-Fi can function in. So… those police cars were hitting lower frequency channels from the WLAN that they don’t support. A quick channel change for the parking lot APs to the few that the M5 does support, and the video was soon flowing from the cars as desired.

This Happens Often on Utility Devices- Be Aware!

I’ve seen this same scenario play out on ticket scanners in stadiums, retail scanners in warehouses, and wireless cameras that all operate in only a slice of 5 GHz. You absolutely MUST understand what radio capabilities are in play when it comes to non-mainstream devices.

These are the cases that often separate WLAN pros from those who don’t understand the important nuances that unfortunately pervade modern Wi-Fi. And that lack of understanding can lead to a lot of wasted time and money trying to fix a problem that is nothing more than poor configuration born of ignorance.

Just how complicated is the question of which individual devices can operate on what specific 5 GHz channels? Let’s ask a good guy named Mike Albano.

 

Of Malfunctioning Boats and Wi-Fi Support

boats_230_odyssey_20742179I have an old power boat, and it has recently taught me a life lesson that very much applies to Wi-Fi support. Every boat should have a name, and this vessel is the Sweet Baboo. She’s a 22-foot Cuddy Cruiser, built in 1985. It’s powered by a 5.7L OMC motor (basically a Chevy 350). This is my first “real” boat, and it has humbled me… A boat like this is really just another vehicle to keep up, but it has mystique and mystery to the new boat owner and the passengers that ride on it, just like Wi-Fi often has mystique and mystery to many networkers and clients.

Just a bit more background, if you’ll indulge me. I consider myself a pretty good shade-tree mechanic, and I do everything I can on my vehicles when it comes to maintenance. I like to save money, and know HOW a job was done, in exchange for my time and skinned knuckles. But I do know my limits, and know when it’s time to get professional help.

Stay with me- I promise the Wi-Fi angle comes into play soon.

Something about being a new boat owner made me kind of silly. Every oddball problem this old boat has had seemed exotic somehow, until very recently. After all, every part on the thing is a “marine” component. It has a marine carburetor, a marine ignition system, a marine gearshift, etc. Which for a while made me think that somehow they were all forged by unicorns in Magic Marine Parts Land, and for whatever reason I’d get stupid when it came time to troubleshoot. I’ve seen Wi-Fi have the same effect on network troubleshooters… somehow everything they know about basic network troubleshooting goes out the window because Wi-Fi is also exotic and different.

Finally, working through one lingering, long-term headache I was able to get my boat mind right, and to draw parallels with Wi-Fi support.

I got through that problem, but I did some really knuckle-headed things along the way. I threw away money and time because my troubleshooting methods were not sound. I looked past “the basics”, and often got sparkly-eyed that my problem had to be some exotic marine thing, just like many people get sparkly-eyed and start dicking with controller settings, adding APs, and taking other fruitless steps to solve exotic Wi-Fi problems that often end up being not so exotic.

The boat problem? Well, Sweet Baboo would start nice, idle great, and run really well at low speed. Give her some gas to speed up this big beast, and the motor would stall or fall back to idle speed at 2,500 RPM every time. Put another way, I had crappy performance.

I went through the troubleshooting steps in the repair manual fairly diligently, but also (in retrospect) bit on many red herrings, hoping for an easy fix. But… even easy fixes can hide behind complex symptoms and pre-conceived notions. I fixated on “it’s GOTTA be this!” at least a half-dozen times after reading online user forums. In those user forums, I latched on to the sage advice of frequent-posters that seemed to be revered by the other folks in the forum. And it turns out they were wrong every time. Or rather, I wrongly applied their analysis to my situation because they seemed to know their stuff.

All the while, because this boat is an exotic marine craft, my brain refused to acknowledge that when I let myself apply sound troubleshooting techniques I have fixed a wide range of cars, computers, F-4 and A-10 aircraft, broken furniture, swimming pool pumps, blenders, and more over the course of my life. I wasn’t letting myself simply proceed as I would normally in the course of troubleshooting anything, because I had never worked on a real boat before. I made it into something it wasn’t, in my mind. I KNOW this happens in Wi-Fi support often.

I ended up needlessly replacing (or tearing into):

  • Every ignition component (some two or three times)
  • Fuel pump
  •  Carburetor
  • Shift cable
  • Electronic shift module
  • Throttle cable
  • Exhaust flapper valves
  • Fuel lines

I’m sure there were other things that I hosed up along the way, too. I broke things trying to fix things- but then again, I was dealing with an exotic marine situation so my buffoonery was OK, right? Well, no- it’s not OK. I’m somewhat embarrassed of my conduct, and I can’t describe the frustration I felt over two seasons of fighting this problem. But again, I have seen people approach wireless support in this same scattered, desperate way.

Anything and everything feels like a WIRELESS problem when you have a problem and happen to be using Wi-Fi. Those not trained or acclimated to the Layer 1 and Layer 2 implications of Wi-Fi can do really dumb, desperate, nonsensical things that they would NEVER do on wired networks. For some reason, we all have things that make us forget what we should know when we most need it. For me, it was this boat. For other folks, it’s troubleshooting Wi-Fi.

After replacing component after component, fiddling with this and adjusting that, I was SURE I had a bad carburetor. There was simply nothing else it could be. So I ordered a pricey replacement… and it changed nothing. Floundering around out in the middle of the lake after putting the new carb on the engine, I was livid. At me, at the boat, at the Boat Gods, and pretty much everyone and everything. I called my wife, and admitted defeat. I told her that we’d have to tow the pig off to a marine mechanic, and take our chances that we could find one that was reputable. But as I was limping the Baboo back to the dock, I had an epiphany. Two thoughts collided in my brain at the same time, and they would lead me to resolution.

I was filthy from repairs, hot from the sun, and pissed-off low-down feeling. I had dozens of hours, and at least a thousand mostly wasted dollars on this escapade. At my lowest, one part of my brain told me “Come on… you’re better than this.” And another asked “listen you schmuck, how would you approach a seemingly complicated wireless problem?” It might sound cheesy, but I was recharged. I pulled up at my dock with a plan. I WAS GOING BACK TO BASICS. This damn boat was the client, and I had a client problem. And it was a similar problem to hundreds of other boats/clients that I had read about online. The solutions were usually proven to be simple, and I empowered myself at that moment to start over, with simple in mind.

Early on in the troubleshooting process, I had pulled the fuel pick-up tube from the gas tank (a 60-gallon monster built into the floor of the boat). I had EXPECTED to find a filter screen at the bottom, but didn’t. Not knowing better, I assumed at that early point that there was no such filter on THIS boat. I was wrong- and simply looking closer at that pick-up tube a second time revealed that the filter was INSIDE the tube where you can’t see it. And it was gummed up with crud pretty good. It was letting enough gas into the system to allow for starting and low-speed operations, but was blocking the increased fuel needed at higher speeds. I had “looked” right at the problem before skipping over it because it didn’t match my assumptions, and at that fateful moment I also turned a simple fix (blow it out with compressed air and carb cleaner) into a two-season exercise in grasping at straws.

I’m not sure what specific analogy to make here to wireless troubleshooting, but I do know that THE ESSENCE of my boat problem and what happens when the unskilled or “blame the WLAN” types get involved with wireless performance problems are the same. Sometimes Wi-Fi doesn’t work because non-Wi-Fi components have faults, but if you lock on to blaming the APs or controller early on, you’ll often never find the issue. Assumptions, poor methodology, and not looking at the basics thoroughly and with an open mind can lead you down rabbit holes. It’s not fun when you do it to yourself, and I really should have known better after decades of honing my troubleshooting approaches.

Just like my boat really is not “exotic and mysterious”, neither is Wi-Fi. But to support either, you have to have the right mindset and not be afraid to just use good sense and thorough checks of the basics as you proceed.

But as I’ve just shown here, that is easier said than done- even for the best of us.

 

Loose Lips Sink Ships (and Network Credibility)

Stop me if you’ve heard this one… A manager- no a DIRECTOR, or a DEAN, or a CIO, or a DOCTOR, or some other person of title– walks into a bar. She tries to use the Wi-Fi, and it doesn’t immediately work, so she declares that the network sucks. And people hear her. Now, because people tend to listen to authority figures, her words get repeated. Pretty soon the off-hand comment, based in one user’s frustration, slowly becomes reality (well, maybe Kardashian-style not really reality).

But… it does become an accepted “fact” by the Person of Title’s circle that the bar has sucky Wi-Fi. And eventually, someone has to answer for that sucky Wi-Fi. It doesn’t matter that while The Legend of Sucky Wi-Fi is growing to epic proportion, hundreds of other of users are enjoying the bar’s Wi-Fi. They just aren’t talking about it, and they don’t have circles of followers that take their word as gospel and pass it on.

Maybe she didn’t mean to cause a kerfuffle, and maybe she did. For some people, if Wi-Fi isn’t working right, it’s everyone’s fault but their own (or their device’s). Regardless- the damage is done. That network has been labelled as bad, and therefor it IS bad, because of who labelled it. So now someone needs to fix what ain’t broke, even if it all amounts to is re-education and demonstration that the network isn’t problematic. That is- IF the person of title is even willing to be convinced (some are, some are not).

Unfortunately, there’s no punchline here.

If you’re reading this, and you are a leader of any sort (the kind that people listen to), the WLAN community asks this of you:

  • Remember that your Wi-Fi client device is like everyone else’s, even though it’s yours.
  • Wi-Fi client devices don’t always act the same way as you travel from network to network. This includes expensive client devices.
  • Not all Wi-Fi networks are set up the same, and sometimes what you expect based on your frame of reference isn’t what happens,
  • None of this means that the Wi-Fi network sucks or is broken.

At the same time, network problems DO occur. Sometimes they impact all wireless clients. Sometimes they impact just you. There’s no way to tell what’s going unless a system administrator gets involved. So… rather than declaring that the network sucks and invoking The Butterfly Effect From Hell For Wi-Fi Networkers, why not help us to help you? Report the problem, including symptoms and a specific time and very detailed location where you experienced your frustration, and wait to see what the outcome is.

A huge part of being a network administrator is basically proving that the network is OK, and solving client-specific problems. The first part often comes from off-hand comments that are blown up into issues bigger than they are because of who said them, and the second is often the reality behind the first.

So c’mon… give us a chance- before you trash the network.