[Madlug] OT: Re: wireless implementation

[Marcin Antkiewicz]

> The scanners are intended to be mobile and I think there is
> an intent to replace the entire wired infrastructure in the
> building with the wireless one.

So, you will need roaming, and there will be more wireless than just 
what needs to be configured to allow for good coverage of the warehouse 
floor.

> Kismet has their own wispy too: http://www.kismetwireless.net/wispy.shtml

Yup, that's one of the clients. Wispy is just a usb wireless (802.11b/g) 
adapter, designed as a very basic spectrum "analyzer". It's a toy compared 
to a real one, but also costs LOTS less than even the real ones. Since 
it's trivial to receive data from it, and full documentation is available, 
there is a number of apps that use it. I like it because the difference 
between not seeing anything more than the wireless drivers report, and 
what wispy reports is HUGE, and well worth the $99, or even $399. I would 
not use it in your case for anything more than just to do a basic 
overview. Expensive electronics has it's benefits and software, and woule 
be far better than the USB dongle.

some links:
http://www.metageek.net/
http://www.kismetwireless.net/wispy.shtml
http://www.cookwareinc.com/EaKiu/
http://www.smallnetbuilder.com/content/view/30072/96/

> Is it more of an exact science to get the APs and antennas positioned
> correctly?  I seem to recall Dale's presentation featuring mostly a
> carpet-bombing approach to the AP placement.

With luck. If your warehouse is anything like others, you will have lots 
of metal (parts, shelves, walls, signs etc). Often such buildings try to 
use APs (anthennas) as if they were bulbs shining light into isles. 
Unfortunately, with wireless you need to worry about channel overlaps, 
interferences, and likely more. If you have machinery, or office network 
you may have to do a magic trying to get all to work. On top of that, 
there are external interferences.

> Kinda what I was wondering.  It would be fun to use openwrt on some
> linksys APs to implement this whole thing.  I'd really be pushing my
> luck though; my wireless-fu is not that strong.

If you can start small - it might be worth trying. Just make sure you will 
be comfortable supporting it once in full deployment. It's easier to find 
someone who will work on "CISCO Unified Wireless", rather than "Our Own 
Bunch of OpenWRTs".

> Um the AP software you mean?  (are you thinking about Openwrt, er..?)

No, whatever is in the barcode guns. Some is written under assumption that 
a modern wired network in in place and, for example, will run status 
checks after every lost frame. If the scanner moves out of the coverage 
range, the system can hang, or the codes get buffered on the scanne with 
no feedback, which results in multiple scans when people "try to get it 
right", and sent bulk once in the range again. But those are pathological 
cases present mostly on equipment that was grandfathered into wireless 
operation.

--
Marcin Antkiewicz