HighWLAN: A Driving Wireless Networkby Casey West
It was one month before Yet Another Perl Conference (YAPC), and I had to decide if I was going to drive or fly from Pittsburgh to St. Louis. To help me decide I did what any other programmer would do, I jumped into an IRC channel about Perl and started talking about driving versus flying. If you know anything about Perl IRC channels, this quickly escalated into a Holy War with Emacs users on one side and Jeep Wrangler drivers on the other. It was hard to tell but I think Emacs came out as the better utility vehicle.
When the chaos subsided, I was greeted by a friendly, private message from Meng Wong saying he was organizing a road trip to YAPC from New York. Meng, Michael G. Schwern, and David H. Adler (dha) were driving my way so I was happy to add a second car and make it a caravan.
The Big Idea
Since we were taking two cars, we needed a decent form of communication. The first choice was using cell phones, but we quickly realized that it really isn't functional for long road trips. Making a phone call from Pittsburgh to New York while both parties are coasting down I-70 in Illinois wasn't my idea of a smart move. I'd be more inclined to run into them to get their attention; it would have cost the same.
It was obvious that we needed to liberate ourselves from the phone companies. Any normal person would have stopped at this point and bought two-way radios. For better or worse, I'm not a normal person. I'm a geek, a geek beyond reason. A wireless network was in order. After all, most wireless projects are created as a means to bypass the telco and their 800 pound gorilla ways.
Nuts and Bolts
I was on a mission. Create the first documented case of 802.11b networking at 85, scratch that, 65 mph. The most important goal of this project was to create a usable, local network between multiple vehicles. This network had to support some form of communication between computers. I had four nuts, Meng, Schwern, David, and me. I just needed a good way to bolt them together.
We needed a way to talk to one another. Between us we had five laptops and at least fourteen different operating systems stemming from the three major offerings. I originally planned to run IRC. IRC is where this idea came from and it was simple enough to get up and running. That is, it would have been simple enough to get up and running if one of us had actually remembered to download an ircd before we started. Since we had no ircd, we did what any resourceful set of programmers would do, we used talkd. Schwern created an extra account on his laptop, running Linux, for ssh access and started talkd on it. That's right folks, we resorted to a protocol invented in 1983. I was three years old when talkd hit the wire.
I talked with Schuyler Erle, a developer for O'Reilly Network and a contributor to the nocat project, about our wireless needs. Once we came up with an equipment list it was time to gather them all up and strap them into my car.
I needed a power source so I got a great deal on a 350 watt dc-to-ac power inverter for $35 USD. Next, I configured my Linksys wap11 wireless access point to work correctly, and I hacked it to 100mw since I don't have the second version of the wap11. I snaked an eight-port hub from my home office rendering my poor wife without a network at home. Last on my list, Aaronsen donated a HyperLink, a high-gain, amplified, omni-directional antenna.
I mounted all this equipment to my center console. On the bottom was the power inverter. Connected to my cigarette lighter I was able to get 180 watts out of it. On top of the power inverter sat my Access Point, the Linksys wap11. At the top of the stack sat the hub and the omni-directional antenna. I cut cardboard inserts to place between each layer then I secured the whole mess to the lid of my center console compartment with Coleman Sleeping Bag Straps and zip ties. This configuration allowed nearly all of the antenna's horizontal signal to escape out my car windows. It also allowed the wireless signal to be pumped to my brain faster than Grant took Richmond. I don't think I suffered any permanent damage. the Confederate Army on the other hand...
Next I began to construct the network. I connected the Linksys wap11 to the hub and the antenna to the wap11 with an RP-TNC to N-Male Pigtail. Then I plugged in all these devices, plus two laptops and a cell phone into two power strips connected to the power inverter.
I mentioned my cell phone because it was part two of my crazy plan. What fun is a network if you can't get it online? I bought a Data Kit for my Kyocera QCP-3035 cell phone. I decided to buy the serial kit hoping it would behave just like a serial modem in Linux; this was not the case. Booting my computer to Windows I installed the software and connected to the Internet via my cell phone. It was not speedy, but for an ssh client and limited browsing it did the trick. Then I connected my laptop to the hub in my car. I had to use a physical line because windows decided my wireless card wasn't good enough that day. After enabling connection-sharing for the cell phone uplink I booted my second laptop to Linux and connected to the wireless network. In seconds I was surfing from both computers over my cell phone. I had proof of concept, I was ready for the road trip.
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