Thursday, December 20, 2012

Breathing Wi-Fi

I often get asked "What's with the velcro on your laptop?"

They are referring to this velcro:

Why the velcro, dude?

The answer is simple: I'm a Wi-Fi engineer.

You see, Wi-Fi engineers are not your typical run-of-the-mill network engineer. Sure, we carry the requisite rollover console cable, USB-to-Serial adapter, know most vendors' CLI interfaces through reflex alone, can whip up a discontiguous wildcard mask for an ACL without blinking an eye, and can diagnose spanning-tree problems in our sleep.

But unlike most other network engineers, we have a very intimate relationship with Layer 1. Whereas route/switch engineers have learned and long since forgotten about Ethernet's physical properties largely because they're not the source of many issues, Wi-Fi engineers eat, sleep, and breath air (you see what I did right there!) Wi-Fi engineers must know the ins-and-outs of RF propagation, signal strength, free space path loss, signal attenuation through various objects, channel planning, and the intricacies of co-channel interference in order to design a network that works.

This requires tools... Wi-Fi tools. Ask any Wi-Fi engineer and they'll show a plethora, nay a smorgasbord, of various WLAN adapters, antennas, and spectrum analyzers. We've all got too many to count; some Cardbus, some USB, some with internal antennas, some with external, some from companies that no longer exist, and some that have been obsolete so long that nobody else remembers them... except for us! Because there's always a chance we'll run into that one customer that still uses legacy equipment that we need to support, test, and emulate.

So when we roll into action, we light the place up!

Light it up!


So when you ask: "What's with the velcro, dude?"
I'll kindly reply: "I breath Wi-Fi, man!"


Breathing Wi-Fi

Until we Associate again!

10 comments:

  1. What brand and model is that cool USB hub?

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    1. It is the Rosewill RHB-330. It also happens to be the one that used to come with the AirMagnet 3-adapter kit.

      You can find it here:
      Rosewill 7-port USB 2.0 Hub

      Andrew

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    2. For some reason in the "Frequently bought together" section is also:
      ORiNOCO 8494 USB Client Adapter - USB - 300Mbps - IEEE 802.11n (draft) by Proxim
      Ubiquiti Networks SR71-USB WLAN USB 802.11a/b/g/n MIMO by Ubiquiti
      ... That's just normal consumers buying those, and nothing to do with wifi analysts, rigth?

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    3. That card is very popular, and is bundled with several WLAN utilities like AirMagnet and Ekahau.

      Andrew

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  2. Looks like the one that comes with AirMagnet
    @CableWiFi

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  3. it's funny that you use a Mac with windows OS and Wifi cards that only work in Windows...

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  4. Hey Andrew, Been meaning to ask about your set up since I saw this come across Twitter a month or so ago, but I assume the three wifi adapters are 802.11n and are capturing traffic on different channels, plus the WiSpy adapter is doing the raw RF capture... correct? Thanks, Dale

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    Replies
    1. Hi Dale,
      Yes, I use a Rosewill USB 2.0 hub and various wireless and spectrum analysis adapters. I have the AirPcap-NX adapters (Wireshark), Linksys USB adapters (Wildpackets), Proxim USB adapters (AirMagnet and Ekahau), Metageek WiSpy DBx (SpecAn), AirMagnet Spectrum XT (SpecAn), and various Wi-Fi adapters for use within the Windows VM for client access and scanning. I use 3 Wi-Fi adapters at once for packet capture on three different channels, which is great for roaming analysis. I will also use a SpecAn adapter at the same time when performing site surveys to cut down on the time required since it prevents having to make a second pass through the facility.

      I'm currently also waiting for better adapters to come out for 802.11ac capture. But 3SS (and more) will be increasingly hard to find in USB form-factor. I'm considering using USB adapters just for broadcast management frame collection and possibly moving to some other method for data frame analysis, such as capturing through a sniffer AP piping the pcap data to the analysis workstation. This might get a little cumbersome to carry one, two, or even three APs around to capture data. I'm not sure yet. Maybe we'll get lucky and a manufacturer will come out with a 3SS USB 3.0 adapter that has external antenna leads to facilitate the spatial separation required. If that happens then I'll buy them! It may look gnarly with 3 adapters and 9 antennas attached to my laptop, but it might be easier than hauling 3 APs around :) And it'll elicit funny looks from people (which would be fun to record on video)!

      Cheers,
      Andrew

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  5. Andrew, have you thought about trying the Surface Pro 2? I'd be interested to see how a hybrid laptop/tablet would perform. It would be easier to carry around that's for sure. Lots of good hardware is going to be released this coming holiday season

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    Replies
    1. Hi John,
      I haven't tried the Surface tablets for any of the Wi-Fi tools yet. I've pretty much standardized on a VM running inside Parallels on a MacBook. I just slimmed down by moving to a new 2013 MacBook Air and the VM runs smoothly as ever.

      Andrew

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