Linux Unwired

Alex Moskalyuk writes "Remember the Best Buy commercial where a puppet asks a woman for a laptop computer, and upon hearing that it's a 'wireless' laptop, starts imagining his life free of strings and limitations? That guy doesn't know it yet, but soon the harsh reality will kick in, ironically kicking him off the wireless network periodically if he uses Microsoft Windows Wireless Zero Configuration or if he wants to run Linux on a laptop with WiFi card that doesn't support Linux. This book, however, is not just about getting your Linux laptop onto the wireless network. Granted, WiFi plays a big role in today's business and personal networks, and three chapters are dedicated to exactly that purpose, but behind that wireless adjective we have a variety of technologies." Read on for the rest of Alex's review of Linux Unwired, from O'Reilly. Linux Unwired: A Complete Guide to Wireless Configuration author Roger Weeks, Edd Dumbill, Brian Jepson pages 300 publisher OReilly rating 8 reviewer Alex Moskalyuk ISBN 0596005830 summary Complete guide to wireless configuration on Linux

Infrared, Bluetooth, 802.11 (in current a, b and g offerings, 802.11i is also being discussed), wireless access points friendly to Linux, United States commercial cellular networks and GPS systems are all covered in a single title that surprisingly fits all of this information into 284 pages. All the chapters can be subdivided into two large parts - familiarizing yourself with the technology (the primer on GPS is pretty good) and running Linux on it (with code and shell command samples and lots of URLs).

Introduction

The authors start up with introduction to wireless, intended for Linux geeks who are not quite up to speed on radio technologies. The concepts of waves, spectrum and radio wave behavior are explained, so later the reader can explain what a retracted radio wave is. Then the first chapter moves on to explain antenna behavior, wireless infrastructure modes and some common problem, like a hidden node in ad-hoc infrastructure. The chapter is well-written, and you're not expected to have an advanced radio degree or ARRL membership to understand the terms.

WiFi cards

Chapters 2, 3 and 4 deal with connecting a Linux desktop or notebook to a wireless 802.11 network. The first issue is that of chipsets used in the wireless card, and even though enough research has been done already, authors discuss different quirks relevant to Intersil Prism, Lucent WavelLan/Orinoco, Aironet/Cisco, Symbol, Atmel, Atheros and Broadcom chipsets. We need to discuss chipsets instead of discussing the actual wireless cards, since some hardware may be shipped under the same brand name with different internals. "A good case in point: the D-Link DWL-650. This radio card initially shipped with a Prism II chipset and was very popular, because it worked on a Linux box. However, D-Link changed chipsets when it released the DWL-650 Version 2, choosing the ADMtek chipset. It is very difficult to tell from the packaging which version of the DWL-650 you are purchasing".

The chapters are done in traditional walk-through mode. They are not HOWTOs or compendia of reference information, available from the manufacturer's Web sites. The authors made an effort to ensure the reader is capable of starting up a wireless connection on Linux box, knowing nothing about it while learning important technology in the process. Certain wireless drivers need to be compiled into Linux kernel, so the task is not for the meek, but with detailed explanation, plenty of URLs and nice fonts and paragraph formatting O'Reilly Publishing uses to differentiate between the text, commands entered at the shell, and URLs, the book is easy to read.

Chapter 3 (available in PDF) teaches the reader how to connect to existing wireless network once the wireless card has been recognized by the system and proven functional. By the time the book hit the stores it was already a bit out of date, since the very first hotspot operator, Cometa Networks, shut down in May 2004. Chapter 4 discusses wireless security, touching WEP settings, a $20 Linuxant utility allowing the user to implement WiFi Protected Access, as well as authentication utilities wpa_supplicant and XSupplicant.

WiFi access points

The issue of WiFi access points is not trivial either, as many vendors out there will ship the product with a Windows app being the only way to set it up. However, for the access point setups that are Web-based, a browser in Linux will do the job. The most Linux-friendly access point include Linksys, Netgear, D-Link, Cisco, SMC, EnGenius, Belkin, US Robotics, Microsoft and ActionTec. Again, harsh reality kicked in between the time the book was written and went to press, and it's sad to see yet another Linux-friendly access point vendor quitting the market.

Not satisfied with commercial offerings out there? Chapter 6 takes the reader into the task of building your own access point. Don't forget that an access point doesn't need to be a compact portable - your old 486 with Linux on it and a wireless card connected to it might serve the purpose. Unfortunately, after all the hardware is bought and assembled, the final product might still cost you the quadruple (in case you go with smaller form-factor motherboards and CompactFlash cards for software storage), so consider this more as a geek project, not a viable solution. The authors use LinuxAP distribution for this task.

16 pages are dedicated to hacking Linksys WRT54G access point with Sveasoft, described as disruptive technology by Robert X. Cringely. The authors also take a brief look at Wifi-box and OpenWRT.

Other wireless technologies

Bluetooth, Infrared, cellular and GPS chapters follow the same chapter plan - first the basics of the technology and simple use case scenarios of what you might use it for, then the hardware needed to implement the wireless technology, available Linux software to do the jobs, accompanied with the list of shell commands to successfully talk to a wireless product, and after that typical applications of the working link.

The authors tested various wireless data plans in the United States, although this data, once again, is constantly changing as the operators buy one another and introduce new data plans. The winner of the quality and the fastest download tests, by the way, was a Motorola v120e phone on Verizon Wireless network. In upload speed tests a Merlin C201 PCMCIA card on Sprint PCS network won. T-Mobile also offers a PCMCIA card for its GPRS network, so the authors install and run it under Linux in Chapter 9.

The last chapter discusses using Linux computers with GPS devices and open-source GPSdrive project for reading GPS data.

The book

For those just venturing into the wireless world, the book would be useful. All the information provided on WiFi connectivity can perhaps be googled and found in various HOWTOs. With wireless operators, GPS systems and Infrared connection one would have to rely on enthusiast sites and newsgroups. Having such informative title that covers all of the technologies would be very useful to a Linux enthusiast.

With that, the book can be quite overwhelming, although it's probably not intended to be read from page 1 to the end. There's usually more than one correct way to do things in Linux, and for each successful project another competitor appears on SourceForge the next day. I like the authors' approach of dedicating most of the chapter space to one, leading, Linux package that seems to be dominant in the field, and then briefly mentioning the others. A notable omission is Intel's Centrino drivers for Linux, as the company is bound to become a leader in the chipset marketplace with 42% of notebooks shipped in 2003 running Centrino chipsets.

But overall the book proved to have a high informational and educational value, not only you follow the steps on setting up wireless technologies on Linux, but you also learn the internals of the technology and why certain things are done that way, but not another.

You can purchase Linux Unwired from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, carefully read the book review guidelines, then visit the submission page.

Comments

Easy solution

[foidulus]

Get an airport(or as I have, an AirMac) card!

/ducks!

Re:Easy solution

[NewNole2001]

If you are using Windows, then look at the link at the beginning of the article to see what might be causing your problems.

That's a genuine problem

[metlin]

From the article --

Microsoft disputes the notion that there's a problem with the way Windows XP works with Wi-Fi.

That's a blatant lie, typical Microsoft attitude.

For the longest time, the wi-fi connection of my notebook would keep dropping and I thought it was because of a bad wireless card.

I changed my wireless card, I tried everything possible.

What I had not noticed was everything I was in Linux, this never happened - no matter what! There are areas in my school where the wi-fi signal strength is particularly weak, and even in those areas I never lost connection from Linux.

Somehow, when I would boot into Windows, my wi-fi link would keep dropping. I still haven't figured the problem yet, I just use Linux instead everytime.

And so contrary to what Microsoft may say, there is a problem with Windows XP (I have the problem whether am on XP Home or XP Pro). I wonder whether they EVER admit their mistakes.

Re:That's a genuine problem

[__Maad__]

I have the same problem mentioned in the Wired article, have seen it in numerous places and know of others who have the same problem.

At the very end of the article they state that you can bring the connection back to life by stopping and starting XP's Wireless Zero Configuration service -- I wish I had known that during some very ill-timed outages! This suggests that XP has everything to do with the problem but I'd still be careful in blaming Microsoft outright. Still, what a disaster.

I wonder now if on my centrino-based Dell laptop it is possible to simply turn off XP's zero config option if Intel's PROSet tools are running. Anybody know?

Re:That's a genuine problem

[networkBoy]

Yes you can. The Intel PROSet driver works far better when compared to the zero config. Set up a list of preferred APs and the PROSet tools will connect in order of preference and NOT continue to bump you around to other APs when they show up as long as any on your preferences are available. If you wan't I beleive you can even turn that off and go for a fully static config.

HTH,
-nB

Re:That's a genuine problem

[jfmiller]

I would like to point all of you to this article at Ars Technica. It explains the problem and how to fix it.

Good Luck

JFMILLER

Re:That's a genuine problem

[swv3752]

The problem with the Zero Config service is a known issue. If your card has its own config util and you disable the zero config util, there is no problem. If you connect with the zero config and then disable zero config, there will be no problem. The zero config has a bug that will drop connections.

Re:That's a genuine problem

[ElForesto]

I could have told you that! *grins* WinXP's utility is useless. On a lot of systems, I couldn't get it to hook up to a router of the same brand 2 feet away with the default settings. I tell Microsoft what it can do with it's utility, install the one from the manufacturer, and BAM, it works.

I should have known better than to trust software from Microsoft over the software from the manufacturer.

Windows Wireless Zero Configuration Problem

[MBCook]

I (and probably everyone else with XP) have expirianced that problem of getting your connection dropped. I learned how to fix it a while ago (and then Ars Technica wrote on it).

The problem is if Windows can find a network that broadcasts it's SSID when yours doesn't, it will try to switch. There are three (or four) soltuions.

1. Find the other network and get the owner to turn off broadcasting
2. Turn broadcasting on for your network
3. Once you are connected to your network, disable the WZC service (set it to manual and disable it). Windows will KEEP the current settings (the ones that work) and won't change them every, so you'll stay on your network. You will have to re-enable WZC if you want to switch networks though
4. The fourth option is to use a 3rd party application to manage your wireless configuration (your WiFi vendor probably gave you one). But if your vendor doesn't have one for XP, this isn't an option.

I REALLY hope that they fix this in SP2, because it's my number one complaint.

Re:Windows Wireless Zero Configuration Problem

[crimbil]

Or #5. Open the properties for your wireless connection. Click the tab for wireless networks. Click the Advanced button. Remove the check from the box titled "Automatically connect to non-preferred networks."

Is it just me...

[Fooby]

or does wireless seem a bit overhyped? I don't own a single wireless device and I don't really see the need yet. Sure there have been times when it would be convenient to have a cell-phone, but most of the time when I'm not home I don't want people harassing me with phone calls anyway. As for 802.11*, the data rate and reliability of ethernet beats it every time for home networking use. Something about carrying around a laptop so I can browse the web at random hotspots just doesn't float my boat. I have wired access at home and at work, and if I need access when I'm at neither I'd go to an internet cafe.

Don't get me wrong, I'm not a luddite and I think these are great technologies, but for myself they just seem expensive and not terribly useful. What I do find interesting is use of WiFi for rural broadband. But that's still pretty novel.

Re:Is it just me...

[CompWerks]

It's just you...

Re:Is it just me...

[tcopeland]

> wireless seem a bit overhyped?

I thought the same thing for a while... but after working on my laptop at home with no wires for the kids to yank on/trip over, I'll never go back. If I run across something interesting, I can carry my laptop in to another room to show my wife. If the living room gets too loud, I can move into the dining room. It's very handy.

And for some reason I still get a kick out of printing something over a wireless LAN connection. Just something odd about clicking the "print" button, with no wires attached, and then hearing my printer downstairs leap into action :-) I don't know why that still amazes me, but it does :-)

Re:Is it just me...

[silas_moeckel]

It's a bit over hyped for big desktop replacement laptops (I own 3 of them) where they need to be pluged into power anyway. But for a PDA bluetooth or 802.11(abg) is rather usefull as they can get out get your mail sync etc, same goes for small light weight laptops that have decent battery life. As far as cell phones it's all about how you use it, I have a cell phone that nobody calls me on unless it's important as in router down (I'm a network guy) as in I take one or two phone calls a business day on it. It's about lifestyle as well, I take an hour plus ride on the train each way a cellphone with bluetooth, laptop and pda allows me to get on the internet to read my personal email web surfing etc without looking like a moron with piles of wires hanging around. At work wifi is nice for laptops that you might be taking around working on the network, and the usual PDA functions. I wouldent call it expensive tech either 802.11b devices run about 20 bucks less than a stack of DVD-R's or a decent sized USB key.

Re:Is it just me...

[GreyPoopon]

or does wireless seem a bit overhyped?

It all depends on your needs or work habits. Here are my personal reasons:

• Wireless LAN at home: I frequently have to work at home. The office where our internet access is downstairs. I like having a wireless signal so that I can either work at the kitchen table or while sitting on the couch in the family room. It allows me to at least be in the same room with my family while I work. I could install a couple ethernet jacks and run cable, but that's a hassle in my house and I would have to break my internet connection to move from the kitchen to the family room.
• Wireless Hotspots: I travel internationally for business. As such, I have rather long expense reports to file. The work needed to file an expense report is not taken into consideration when projects are assigned to me. At the moment, our expense reporting system requires an internet connection. It's nice to be able to handle my expense reporting while I'm in an airport or a cafe somewhere through wireless. It's also nice to be able to get to e-mail and communicate with people at work while sitting in the airport. This is especially true when I'm traveling during a business day.
• Cell Phones: OK, in my mind these are actually less useful. But good reasons to have them are:
  1. Unlimited calls to my wife's mobile regardless of where I am in the country.
  2. Nationwide long distance included
  3. Backup source of connectivity for my laptop (GSM + GPRS)
  4. A way to call for help in an emergency where there's no phone around

Re:Is it just me...

[Marble68]

On the same vein. My wife kept asking me to stand up WiFi @ home. I ended up getting the Microsoft 700 series (which they're not going to make anymore) and I must say I don't know what took me so long.

I love being outside by the pool and taking care of a backlog of emails or simply using my Mod points.

But speaking of printing; we have an upstairs game room thats my wife's office. My office is directly below hers. Anyway, the cats LOVE to lay on her desk and look out the window at the trees.
I get a HUGE kick when I print something and you'd think someone had thrown teargas into the upstairs room and several cats come barrelling down the stairs with their hair firmly perpendicular to their skin.

Great fun.

:)

Linux and Wireless

[duncanmacvicar]

I was one of those users who read about DWL-650, went to buy one and came back with a DWL-650+ without noticing it. It sucks. At my Computer Sciense Departament (like 12 AP), my laptop gets frozen because the driver and the computers turns very unstable. At home it works well because I have only one AP. Wireless tools are very primitive also. You can't scan networks not being root. I started writing a KDE tool emulating the funcionality of the new Win XP Service Pack 2 wireless tool but libiw is a pain. I ended importing a patched sources (from some Ximian guy) to use it. Still havent figured how to scan available networks being a user. Design flaws from a server oriented operating system.

DWL-650

[Nemi]

I just got this card working on an IBM thinkpad 240. I spent a good week or more trying to get the prism2 drivers to work because all documentation I found said that that is the chipset it had.

After going through many different drivers and kernel compiles, I Later found that some 650's not only have an ADMTek chipset but some also have be a Realtek chipset. After trying the ADMTek drivers I found my particular card had a Realtek chipset and it came right up using the ndiswrapper driver using the windows Realtek driver (the driver supplied by d-link on the cd would not work. I had to get the windows driver from Realteks site). The thing works like a champ now with Fedora core 1.

Honesty In Advertising

[Croaker-bg]

I am an avid unix/linux user and I pretty much prefer to run my boxen in non-Windows mode. I also am an information security professional and use many tools such as Kismet to do wireless discovery. After much reading and research I decided on a Cisco/Aeronet card as my card of choice for both sniffing and wireless use in Linux. Well low and behold once I got the Cisco card, which was stated as being supported in the OS, I managed to get it installed and compiled to be used as a sniffer but to date and after a solid year of trying I have not been able to get the damn thing to work as just a network card. After months of frustration I finally gave up and went and bought an Orinoco card that I thought I would use for both sniffing and network access. Again, I managed to get things compiled and working this time with network support for the Orinoco card and no ability to sniff. Although both vendors claim full functionality within Linux I am to date still carrying around two wireless cards to get the job done. Sadly, when I boot Windows and plug in either card in XP they both seem to just work. Ah, the bitter irony.

Computer Book publisher's business plan

[cerebralsugar]

1.) Get a 'high-falootin' title (PHD, MSCE, etc).
2.) Paraphrase information freely available on the net.
3.) Blow college professors and get them to use it as a text book for their class!
5.) PROFIT!!

Re:noooo

[kfg]

. . .it drives me nuts when people get all uppity over someone elses use of language, and attack with even poorer use of the language.

I don't need no instructions to know how to rock!!!!

I that case where would you like me to send your rocking instructions?

KFG

Mapping Wi-Fi under Linux

[drewzhrodague]

There are quite an assortment of GIS tools available for Linux, too, for those of us mapping wi-fi. Check out Mapserver, GRASS, and PostGIS.

Power Save

[Foxxz]

Turn off the power saving options for the wifi card. do not allow windows to put the device in sleep mode and use the least power friendly option avalible for the card. these have to be changed in the driver prefs under the hardware management. i was getting the exact same problem even when sitting >10ft from the ap. when i turned off all the power save features for the card these problems went away.

-foxxz

screw it, use driverloader

[np_bernstein]

So I had a belkin card which was supposed to be based on an orionco chipset; it wasn't and it didn't work. I got a netgear, because that's what they had at comp-usa and I didn't want to waste all my freetime driving around looking for a prism2 chipset where I could be sure it was a prism2.... I got the thing, tried it, didn't work, got a copy of driverloader : done.

I'm three days into the evaulation period and I'm giving them my $20 for the software. It's too easy this way to go the free/annoying route. 'Sides, at the amount of money I end up earning/hour, spending two hours of my life to get a wireless card working it costing me more that $20.

WPA was the source of my woes

[EkiM in De]

I discovered that both of my Windows Laptops were dropping the connection approximately every hour and it was driving me nuts. (They are a Dell with a Broadcom 4306 (802.11g) and a Centrino Toshiba.) Even with a Linksys 802.11g WAP and an SMC 802.11b WAP I was still getting the disconnections.

Eventually after one night's worth of Windows's Eventlog data, when I forgot to switch my laptop off, I realised that there was almost precisely an hour between disconnections. An alarm bell rang in my head because on the Linksys there was an option for altering the "Group Key Renewal" for WPA. This was by default set to 3600 seconds.

One quick switch back to 128bit WEP and my connection is rock solid on both laptops.

That example seemed deliberate

[SeaFox]

Why do I feel like that Best Buy Puppet example in the begining of this story was tacked on simply to stick in a Microsoft Bash.

Since the book was about Linux, there was no real practical reason for including it. Is the book going to tell how to get around the XP problem?

No.

That's a lot of type to say simply "some wireless cards aren't supported by Linux out of the box".

Absolutely

[NineNine]

Absolutely. Wi-Fi is no where as near as reliable as good ol' ethernet, and won't be for a while. Certain cordless phoens even disrupt wi-fi. It's cute for home use, but I would *never* rely on wireless for a business use. It's just not reliable enough. I *need* my network up 100%, or my rent doesn't get paid. Wi-fi is cute, but it doesn't cut it for me. On top of that, ethernet is cheap, and very, very easy to run. At my business, we have suspended ceilings with hundreds of feet of Cat 5, and a few $20 switches.

personal experience with xp & wifi

[Lord Haha]

as much as the many complaints about xp & wifi I have not had as many problems, I have found if you turn off wep (which is pretty much useless anyways) and leave only mac address protection to your wireless router the amount of lost packets/connection drops to next to nothing. Mind you it does mean someone might find out im posting at slashdot (oh the horror!) and I have to manually encrypt files that have sensative material (which you should anyways) Under Linux though as much as once the connection is started its great, getting that 1st connection is hard as hell, showing windows (in general) one point where it beats linux consistantly (and its not our exactly our fault either) hardware support.

SSID rebroadcast is NOT a solution

[blunte]

That will allow the machine to quickly reconnect, but it doesn't solve the actual problem. It just remedies the symptom a bit.

It is unacceptable to be disconnected, even if you are immediately reconnected. This is the situation of one of my clients.

His PC bounces while his two laptops, both on the same desk, all of which are no more than 5 feet without obstruction from the wireless router, never have a problem.

Plus his PC didn't always do that. And changing router frequency channels doesn't solve it.

Dumping the MS config and moving to a manufacturer connector is the only solution for hosed XP machines like this.

Renewed competion between broadband providers

[j1m 5n0w]

Besides user convenience, one of the benefits of wireless networks (particularly long-range wireless) is that they can compete directly with DSL, Cable modem, and landline phone service. My parents live out in the country on a hill about five miles from the nearest large town (McMinnville, OR). They have fast internet service thanks to a reasonably forward-looking ISP who set up a wireless network using radios from waverider. Unfortunately, the waverider site doesn't list prices anymore (I believe they used to sell an access point and five client radio modems for about $5000 or so, and additional radios were about $400). It uses the 902-928 mhz ISM band, so there's no FCC license required, and the line-of-sight requirements aren't as strict as 802.11. Once 802.16 (wimax) gets established, similar performing, cheaper, non-proprietary radios may become available.

This is a great way to compete with cable modem and DSL without needing to deploy much infrustructure. Any well-motivated party can set up one of these networks. It may also compel landline internet providers to offer higher throughput and better service, which is good for everyone.

-jim

Re:Broadcom support

[Dielectric]

From my dealings with BCM, I wouldn't expect them, ever. They have a profit model where they provide basic functionality and docs with their product. Everything above that, including non-MS drivers, is pretty much an additional cost, typically assessed as an NRE, and can run to the tens of thousands of USD. So you get two results:
1. No 3rd party will write Linux drivers, nor will BCM, until there is a clear need from a profit standpoint. This is like trying to get major software vendors to make a port.

2. BCM certainly won't release the docs, because then they'd lose this part of their business.

Someone, please, please tell me BCM is going to play nice and let us have a Linux driver. I'd like to hear that I'm wrong here, but just about every BCM product has worked this way.

Brain Hurts

[pete-classic]

I didn't read the actual review. I fear that I am already perminantly brain damaged from the summary.

I swear it said something like "This book is not about what the title says it is about, except that three chapters actually are about that, but the rest isn't. But that stuff is related. Fuck Mocrosoft."

Oh, and somehow it lead into all that with a reference to sock puppets.

I might be wrong, but I am mortally afraid of re-reading the summary given the results of the first read.

Is the actual review any better?

-Peter

Best wireless card for linux?

[ceswiedler]

Any recommendations on the best wireless card for Linux? Both PCI and PCMCIA.

Ah, the bitter irony

[lorcha]

Not sure why your cards working in XP is ironic, but whatever. Anyhow, what distro/kernel are you using? I ask, because under Knoppix, my D-Link and Orinoco cards "just work", as you say. I didn't have to compile anything, tinker with anything, or ... well.. frankly even do anything except insert the card into the PCMCIA slot.

Since you are into security, perhaps you would be happy getting an STD? Security Tools Distribution, that is. That livecd will likely have any tools on it you need as well as detect your cards without any fuss.

Best of luck.

Linux Wireless Zero-Configuration

[akp]

As long as a lot of people are complaining about XP's wireless configuration, could someone point me in the direction of the corresponding tool for Linux? I'd really like to be able to bring my laptop out of suspend in a new place and have a little dialog pop up showing me what wireless networks are around.

For added points, it should work with any wireless card and driver that is supported under Linux.

-allen