Linux Makes Wi-Fi Happen in New York City
Public wireless networks are hacker community outreach. For hackers, it's a way to bring broadband Internet to public spaces. For users in streets and parks, it's a more civilized public life. Unwired from providers, public Wi-Fi makes the Net a gift—a civic grace akin to parks, sidewalks, boulevards and libraries.
In May 2003, when the FCC continued deregulating ownership of what we used to call the “public” air waves, the agency made a big deal about “saving” what was left of “free over-the-air” broadcasting. The Internet, however, needs no deregulation—or regulation—to make it free over the air. All it needs is generous technologists, citizens and civic organizations. That's what we have in New York City today. And, their work is remarkable to behold.
Some public Wi-Fi efforts are largely municipal. That's the case with Long Beach, California, which provides a large public “hot zone” in its downtown and another at its airport. Other efforts are driven by technically savvy volunteers, such as in Austin, London, Perth, Seattle, San Francisco and many other places. Companies also are doing their part. In Asheville, North Carolina, Natural Communications offers a public hot spot called the BeamPost. New York, however, is different breed. It's all the above.
Although New York ranks 27th on Intel's list of “most unwired” cities (Portland is first), it is perhaps the best example of a working consensus between hackers, businesses, government and nonprofits about the need for free public Wi-Fi. This consensus is what gave rise to NYCwireless, a self-described “loose collection of interested minds”. NYCwireless has two missions: to provide free public wireless Internet access and to provide a forum for wireless technology development.
The founders of NYCwireless are Anthony Townsend and Terry Schmidt, partners in Emenity, the company that has been building out the new NYCwireless infrastructure in New York. Both NYCwireless and Emenity are products of public and private symbiosis—same with its customers, which include publicly funded neighborhood associations created for the purpose, among other things, of building out infrastructural improvements, such as public Wi-Fi in the parks.
In May, New York's City Council issued a staff report that recommends a restructuring of the city's fractured broadband procurement methods, a new fiber/wireless metropolitan area network (MAN) and public Wi-Fi networks. As an example of the latter, it says a potential Prospect Park Wi-Fi network would cost $192,000 to create but little to maintain. That report opens with special thanks to Anthony Townsend, who is also a Research Scientist at NYU's Taub Urban Research Center, where he has produced a pile of wise and seminal papers about the growth of the Internet in urban settings. Terry Schmidt's job is turning Anthony's vision into reality. Terry is Emenity's CTO and the hacker behind Pebble Linux, the stripped-down Debian used in NYCwireless access points.
Pebble Linux: Debian for Wi-Fi
If you want to set up a public access point (AP), however, you'll need something that gives you a high level of functionality and control, in a compact and reliable system. Something, of course, that runs on a form of Linux. Pebble Linux is a tiny Debian-based Linux that's the basis of a load-and-go, fully-featured, (relatively) easy-to-customize, no-moving-parts AP. Created by Terry Schmidt of NYCwireless and maintained by a pack of user/hackers, Pebble is Debian, stripped down to a size and shape that fits cozily on a 128MB Flash card. Because it's Debian, adding and removing packages is relatively easy. Here's how Terry Schmidt says he did it:
I stripped out all the documentation, all the Perl stuff, a lot of the binaries, all the packages I didn't think were necessary. I got it down to 44MB. I wanted the functionality of a real distro like Debian in a size that would fit in a CompactFlash in something like a Soekris box. I could do apt-get install apache and bang, we'd have Apache. So the full package manager is there, with all the ease and functionality you'd expect.
Terry's README (www.nycwireless.net/pebble/pebble.README) file adds:
Its biggest advantage is that it mounts read-only. You don't have to worry as much about wearing down the CompactFlash, and you don't have to worry about doing proper shutdowns. Unplug and plug in as much as you want.
There are two packages in a base Pebble image that aren't installed as Debian packages:
HostAP: a driver for Prism-based 802.11 cards that provides the best support for running an AP, as opposed to a client. This is available as a Debian package, but Pebble uses the latest version from CVS, because it associates better with 802.11g clients.
NoCatAuth: more details below.
Three optional packages also are available:
“Pebble mesh” support, which allows multiple Pebble machines to form a transparent mesh. This means that a user can roam without changing IP addresses or losing network connectivity. AP mesh capability (which is, IMNSHO, unbelievably cool) is the most interesting add-on for people building public wireless networks. You can build an arbitrarily large wireless hot zone, and—best of all—the devices autoconfigure, so adding or removing a node doesn't require modifying the configurations of the other nodes.
Support for an ELAN SC520 watchdog timer. In particular, this addresses the built-in watchdog timer on the Soekris. This allows for automatic reboot in case of software glitches. It's particularly useful when the AP is mounted someplace that's hard to access (like in a kiosk in a public park), or the AP isn't actively monitored (like almost every AP). This, along with the read-only filesystem, makes a Pebble system close to zero-maintenance.
Support for running as a bridging firewall.
Pebble runs well on a 486 processor or better and requires no more than 32MB of RAM and 128MB of “disk” storage. It probably will run on that old 486 in your closet, but for less than $300, you can buy the very cool and very tiny Soekris 4511-20 and a wireless card—and be up and running in no time. If you're hard-core, you can buy the Soekris with no power supply or case and build your AP for less than $250.
Pebble is designed to work out of the box with any Intersil Prism2 or Prism2.5-based 802.11b card, such as the Linksys WPC11, the D-Link DWL-650 or the Compaq WL100 and WL200. With some simple configuration, it should work with any Linux-supported 802.11b card.
When you're ready to get started with Pebble, see the project site. As an alternative to Pebble for the /truly/ minimal-minded, you might consider WISP-Dist (Wireless ISP Distribution—leaf.sourceforge.net). WISP is incredibly tiny; it fits on an 8MB Flash ROM and 16MB of RAM. It's not nearly as full-featured as Pebble (it's a really-vanilla AP) nor is it as easy to customize.
To set up your own public AP, all you need is an ISP that doesn't care if you share bandwidth, an AP, a target service area, a directional antenna and motivation.
Some ISPs, like Bway.net in New York, are happy to let you share the bandwidth for which you pay. Others, like Time-Warner Cable and AT&T Broadband, crack down on users sharing bandwidth. A local public Wi-Fi organization can help you locate an ISP with suitable terms of service or help you lobby your ISP to change their terms of service. Freenetworks.org can help you find your nearest public Wi-Fi group.
NYCwireless' mission is to target outdoor public spaces, such as parks. Placement means everything. As Doc and Britt discovered when trying to reach Tudor City's park from high in a building half a block away, distance is a problem. A highly directional antenna can help by concentrating energy in a narrow beam, but a nearby omnidirectional (omni) antenna outperforms a distant directional antenna nearly every time. Bryant Park is served from a number of points by a combination of omni and sector (directional) antennas on the tops of kiosk buildings. City Hall Park is much better served by a sector antenna on the store across the street. Verizon gets great curbside service from simple omni antennas on public phone booths.
Antennas are not commodities, but they don't have to be expensive, either. And, sometimes simply putting an AP in a window does the job. Ben Hammersly did exactlly that for Kynance Mews in London and served a whole street, including two outdoor cafes. Motivation, of course, is up to you.
Doc Searls is Senior Editor of Linux Journal
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