Extract From Byte Magazine - August 13 - All about Wi-Fi

[Steve Bildermann]

As BYTE is now a subscription service I thought some people might enjoy reading some extracts.

Will Wireless Networking Shout Itself to Death?

The nomenclature for wireless networking is indeed confusing, so a quick recap for those who came in late: 802.11a comes earlier in the IEEE definitions, even though it runs at a higher frequency than 802.11b. Meanwhile, 802.11g runs at speeds up to 54 Megabits per second, on the same band as 802.11b. Almost everyone drops the "802" part as a shorthand, so "802.11b" becomes ".11b." 802.11a was once known as "Wi Fi5." The Wireless Fidelity Alliance (http://www.wifi.org) now wants to refer to .11a, .11b and .11g as just "Wi Fi." Longtime readers will remember that Microsoft's Allchin told the WinHEC 2002 conference about Wi Fi, which he pronounced "wiffy."

On to the story: If common sense holds out, the United States Federal Communications Commission (FCC) may adopt the same rule that their European equivalent has, and 802.11a will have about 80 percent more channels to choose from.

This takes a little explanation. 802.11a operates on the 5 GHz band, until then solely the province of search radars. You may also hear 5 GHz called the "U NII band," for "Unlicensed National Information Infrastructure." (For those keeping score, 5.470 5.725 GHz is right in the middle of the U NII band.) The FCC originally set this chunk of radio spectrum aside for schools, who were having a problem putting in enough wire to hook up all the classrooms. The IEEE and a great lot of manufacturers planned a version of .11b running on this band, and in the last year there've been hundreds of .11a products, or combo .11a/b products.

Back to 802.11a. The Europeans decided to allow "dual use" of 5.470 5.725 GHz, so .11a could coexist with existing radar. As part of the deal, .11a radios must cease using this part of the band if they detect radar using it a fair bargain. The FCC is, so far, following their lead, and should issue new rules later this year. And just in time: 802.11b, the older wireless networking we all use, is starting to get crowded.

Why? For communications, 802.11b competes with every other device radiating in the 2.4 GHz band. (Radio nerds also call 2.4 the "ISM band," short for Industrial, Scientific and Microwave.) That tiny 100 milliWatts competes with a great number of other sources. 802.11g also puts out 100 mW on the same 2.4 GHz band as .11b, and all .11g gear is backward compatible with .11b. Apple calls .11g "AirPort Extreme," D Link "AirPlusExtremeG." 802.11g communicates at speeds of up to 54 Mbit/second, as compared to the 11 Mbits/second (Mbps) promised by .11b. Promised is the right word, since we've never seen anything close to the posted speed limit in anything but lab conditions.

The largest source of interference on the 2.4 GHz band is microwave ovens, as anyone who's tried to make a call on a wireless phone while nuking popcorn will tell you. Microwaves radiate on this band because it's absorbed best by water. That, of course, is why microwave ovens are carefully designed to avoid leakage. Before you wrap your .11b card in aluminum foil to keep from boiling your blood, remember that the emitted power is about a tenth of a Watt. You'll get more of a suntan from the bulb above your desk. Comparatively, the radio in an 802.11b access point puts out nothing. That makes it safe, but it also allows interference.

Speed Matters

For casual use, like checking e mail or browsing the web, 11 Mbps is just fine. But if you want to move a gigabyte file to your laptop without connecting a cable, the faster the better. Interference only makes the greater possible top speed more important. Reason: Whether you live in a technologically savvy part of Hollywood or a crowded Tokyo apartment building, there will be interference. Interference will only increase dramatically as people get more used to wireless networking. Already, areas like New York's Times Square are chock a block with commercial .11b providers, including McDonald's, the Easy InternetCafe, and Verizon. During a recent stay on Manhattan's Upper West Side, my son Alex detected (heard?) six 802.11b access points; only two of them were running any sort of security. Free bandwidth for the asking, assuming they didn't destructively interfere. Just log on and go.

Now, with 802.11 of any flavor, you'll get some throughput, regardless of how many microwaves, cordless phones, old HomeRF boxes, BlueTooth equipped computers, Mira/Smart Displays or competing .11b access points are in range. No matter how much of your neighbors' hardware is shouting at the top of its lungs, some stream of bits should get through. 802.11b uses Direct Sequence Spread Spectrum (DSSS), which reduces the problems with interference, and lets multiple devices share the same channel. Sort of.

Perhaps I should say, "You'll get some amount of throughput, until you don't." Even with spread spectrum cleverness, 802.11b is still radio, and the laws of physics (and information theory) still apply. If the incoming signal is too loud, the radio's front end will detune (get less sensitive). If there're too many competing signals, the radio won't be able to discriminate and pick up the one you want. On Windows XP, this can exhibit as the wireless networking icon in the System Tray constantly cycling between "Disconnected," "Connected Signal: Poor" and "Connected Signal: Good." The more devices (particularly access points) on the channel you're trying to use, the more likely you'll see this behavior.

This unpredictable petulance exhibits itself in different ways, with different radio chipsets, and even different firmware revisions. It's not like you can put on a pair of headphones and tune the Hallicrafters short wave set until you hear WWV clearly; the radio is constantly pulling signal out from below the noise floor and reconstructing bits.

So how does 802.11g enter into the picture? Remember, .11g runs up to 54 Mbits/second, in the same chunk of frequency as .11b does for 11 Mbps. It's more "spectrally efficient," to use the buzzphrase. So, given a higher speed limit, the more likely that a given number of bits will get through in a certain amount of time, assuming the same interference. In short, .11g is more likely to send your file in a given time period than .11b.

Unfortunately, any .11b gear older than about 6 months isn't going to be upgradeable to .11g. The key phrase is ".11g draft compatible," and any gear so labeled should have "real" .11g firmware updates available Real Soon Now. The D Link gear we've been using runs at "speeds up to 22 Mbps," because their chipset vendor (Texas Instruments) put in some clever and incompatible tricks. But it isn't going to be upgradeable. Much of the new D Link gear (and everyone else's) is .11g, but look carefully before you buy. Just days after the .11g standard was finalized the Apple AirPort Extreme cards and Access Points had new firmware fully compliant with the full final .11g standard.

802.11a, for now, doesn't have quite so many products sitting on its band, so it's more likely to stay less crowded and more useful than .11b or .11g. I did see a recent Fry's ad touting a 5 GHz cordless phone, so there will be some other uses.

What should you do? If you're already using .11b, and you're happy with the performance, play on. Do turn on WEP (Wired Equivalence Privacy, read on), because a little security is better than none. Until your neighbor fires up his own access point, your throughput should only be limited by the microwave oven and the cordless phone. If you live in a densely populated area, you should pick a channel that's not in use. If you still get unpredictable behavior, say the wireless networking on your laptop just can't sustain a connection, it may be time to upgrade to either an .11g or a combo .11a/b/g network.

Peter Glaskowsky's advice on channel picking: when creating an 802.11b network, put it on Channel 1, 6, or 11 if either of those is open. If they are all in use, select a channel near the weakest of those three. For example, if 1 is weakest, use 3.

In no case do I consider wireless networking a 100 percent replacement for a real wired Ethernet networking, at least not yet. The risk of sudden, inexplicable sags in throughput are just too great, and Ethernet carries a lot more data per minute. It's also a lot more secure.

What about the long term future of 802.11, in all its flavors? Good, actually. There are a lot of very clever engineers spending a lot of time and money making much more clever access points (APs), particularly for high traffic areas, such as Times Square. The intelligent APs will compensate for increased interference, even for (by today's standards) lowly 802.11b. .11b is going to be with us for 5 years or so, but .11g will become the low end standard within 12 18 months. .11a is going to roll out first as a supplement, then slowly a replacement for, .11b and .11g. And, assuming everyone does their jobs right, as you wander through Times Square, it'll Just Work.

WEP and Apparent Privacy

Wi Fi includes a security mode called "Wired Equivalent Privacy," which (per the name) is supposedly about as secure as an Ethernet connection. It isn't, but it's a lot more secure than no privacy at all. WEP is standardized at two different key lengths, 64 bit and 128 bit. The longer keys are somewhat harder to break, therefore better. D Link (and others) advertises "256 bit WEP," with even longer keys, but this isn't a standard, and is guaranteed to interoperate only with like gear.

Most wireless gear manufacturers make it relatively easy to set up WEP if you buy everything from them, but of course if you get a Tablet PC it'll be built in. The biggest frustration for me is the utter lack of standards for how you enter the WEP key itself: One brand of Access Point wants it entered in a different way than another, the manuals don't show examples, and since the WEP key is a password it's often shown only as a set of asterisks. I'm sure one reason so many folks use wireless with the default settings is they get frustrated trying to set up anything fancy; this is a good example.

Nearly all Access Points (APs) let you turn off "SSID broadcast," aka the "Service Set Identifier": the wireless network's name. Turning SSID broadcast off makes it slightly harder for the nosy to find your network, the first step toward breaking into it.

Conclusion: If you're setting up wireless for anything but the most casual use, consider just what you might be making available to the whole world. If you can't bear the risk of disclosing the traffic on your wireless network, get someone to help you set it up properly. If you're buying new gear, and speed is important, consider spending a little more for an 802.11g network. Choose a wireless channel that's not in use, by monitoring what's out there with your wireless card's "site survey." Turn on 128 bit WEP, even if it means calling tech support to find out how the AP and wireless cards want the WEP key entered. Turn off SSID broadcast, and make a note of the SSID, so you can find it again when new machines need to connect.

The wireless industry is slowly improving security, without, I hope, sacrificing interoperability; Microsoft and others are now supporting "Wi Fi Protected Access" (WPA), a baby step, while the IEEE formulates 802.11i, expected late in 2003. (For more on WPA, see http://support.microsoft.com/?kbid=815485.) In the meantime, treat 802.11a/b/g wireless as anything but secure out of the box.

Apple Polishing

Many of my friends are telling me it's time I bought an Apple G 4 Powerbook. As Peter Glaskowsky of Microprocessor Reports puts it, with Apple everything is either very simple or it's impossible, and a lot more things are possible now.

But: Apple just announced the first 64 bit personal computer intended for ordinary users, the PowerMac G5. Peter Glaskowsky wants to be quoted as saying the PowerMac G5 is the shizznit, and promises that word will be in the dictionary in ten years. We'll see. Anyway, there's been a bit of a brouhaha concerning the benchmarking of this beast, and I don't want to get into that; suffice it to say that it's a pretty fast box, it's 64 bits, and it runs UNIX.

That's right with OS X, Apple took their user friendly and graphically appealing operating system and bolted it on top of a FreeBSD variant called Darwin. The idea was to provide the benefits of the Apple user friendly interface on top of a powerful UNIX based core.

And according to my friend Roland Dobbins, they've succeeded. Roland's a hardcore *NIX enthusiast and network engineer; if it can be done with routers or switches or firewalls or Linux or Solaris or UNIX in general (or any combination of the above), he either knows how to do it or can figure out how to do so in short order. Roland's been a Linux enthusiast for many years, patching and compiling his own kernels, and generally living a Microsoft OS free life for quite some time.

Roland bought a 15" Apple PowerBook a couple of months ago, and has substituted it for his IBM ThinkPad T30 running Slackware in other words, it's now his main machine (Roland is one of those people who switched his primary machine to a laptop early on, so that he'd always have all his files and scripts and utilities with him at all times). He tells me that because Apple has switched to a UNIX core and embraced the Open Source community and opened up OS X to open source developers (http://fink.sourceforge.net/), his PowerBook is a portable and powerful UNIX workstation which he essentially doesn't have to administer, and that he's consequently gained several hours a week back by not having to constantly tinker with it in order to get it to do what he needs.

Coming from someone like Roland, that's a pretty strong endorsement. In the next few months, I plan on checking out some of Apple's latest offerings, and will report back. In the meantime, you might want to take a look at their latest offerings if you're in the market for a new machine. Apple isn't cheap, and you have to accept their way of doing things if you buy into their technology, but the payoff can be worthwhile.

Of course with UNIX it just isn't true that everything is either very simple or impossible. UNIX is a way of life!

Winding Down

For forty years, Richard Helms served his country in one capacity or another within the world of intelligence, beginning as a cub reporter and intelligence stringer in Nazi Germany and finishing as Director of Central Intelligence, or DCI, responsible not only for running the CIA but for the U.S. intelligence community as a whole. Helms passed away last year; his posthumously published memoirs, A Look Over My Shoulder: A Life in the CIA (Random House, 2003; ISBN 037550012X), is the first book of the month, and is definitely a worthwhile read for anyone interested in getting a glimpse of the role intelligence played during a critical period in the history of the United States.

The second book of the month continues the same theme: Philip Taubman's Secret Empire: Eisenhower, the CIA, and the Hidden Story of America's Space Espionage (Simon & Schuster, 2003; 0684856999) is an extremely valuable contribution to the history of what is colloquially known as the Cold War (I call it the Seventy Years' War, myself, for reasons which should be obvious). President Eisenhower one of the shrewdest and most visionary chief executives this country has ever elected was an early and enthusiastic proponent of intelligence as a means of both preparedness and of averting accidental war in the nuclear age. Mr. Taubman relates how the best and brightest at the CIA, Lockheed, Boeing, RAND, Eastman Kodak, and other familiar organizations developed from scratch the basis for the truly revolutionary photointelligence, SIGINT, and other technical means which are to this day critical to the national security of the United States and her allies. There are many unsung heroes whose stories are finally told in Secret Empire, among them those of Americans who lost their lives when their reconnaissance aircraft were shot from the skies over the former USSR. The Cold War wasn't always so cold, and Taubman's book is a much needed corrective.

The computer book of the month is Jim Keogh, The Essential Guide to Networking (Prentice Hall PTR, 2000; ISBN 0130305480). Like all the Prentice Hall "Essential Guide" series, this is both an introduction and a handbook. It starts at quite a basic level, and while it won't make you a professional network administrator, it will give you a pretty good idea of what the job entails. John Vacca's Essential Guide to Storage Area Networks (Prentice Hall, 2001; ISBN 0130935751) does the same thing for the SAN, but goes into enough technical detail to be useful to SAN administrators. I've seen a number of the Prentice Hall Essential Guides now, and they're all very well done.

The movie of the month is Pirates of the Caribbean, a rip roarer of an action picture that may revive the pirate movie as a viable entertainment. If that's not your cup of tea, The Hulk is a pretty straight translation of the comic book to film. There's also an excellent straight comedy, Legally Blonde 2 with the delightful Reese Witherspoon. One of those ought to lure you out of the house this month. If you're going to see The Hulk see it in a theater. Like King Kong, it's just not very impressive when the monster is only five inches tall!

The game of the month is Microsoft Game Studios' Rise of Nations. I'm not a big fan of real time strategy games; I prefer turn based games because my life tends to be an interrupt driven system, and click fest games take too much attention. Of the RTS games I have seen recently, though, this is one of the best, with the action and planning all smoothly blended. Of course some of the situations can get a bit ridiculous with World War II era warships confronting wooden ships of the line (steel wins every time), but in general it's both challenging and fun.

[Taro Toporific]

As BYTE is now a subscription service I thought some people might enjoy reading some extracts.

Will Wireless Networking Shout Itself to Death?

WiFi bah.
I've given up on it here in Japan. Flat-rate 128mbs Edge-H etc. via PHS is a far easier and safer solution. When I get my Sony Clie' UX-50 with Bluetooth, WiFi and an Edge-H card I'll report back with a comparison of what real-world wireless in Japan. In downtown Tokyo, Tamachi free WiFi is great...other places even in downtown Yokohama, it's zero. On the other hand, Edge-H etc. always works, EVEN on the farm in bumfarking Shikoku island where ADSL doesn't.

[Big Booger]

I run a wireless network at home for my laptop. Loo surfing is an amazing adventure, especially with a no touch toliet

It runs at 11mbit/sec but the most I usually get out of it is around 8-9mbit. Which is really fine. Takes about 7 -10 minutes do transfer a whole CD. I am running the 802.11b wi-fi which I purchased nearly 2 years ago and has served me well. If I ever do get a new wireless router, I'll be certain to pick up a 802.11g compatible NIC/router.


Interesting read as always. Thanks Steve.

[Taro Toporific]

I run a wireless network at home for my laptop. Loo surfing is an amazing adventure, especially with a no touch toliet ...
Interesting read as always. Thanks Steve.

YES! Thanks Steve!
My home Ti PowerBook is on 802.11a WiFi wireless that won't even make it 4m to my toilet for some seriously constipated surfing.

[Big Booger]

In fact, I think I'll post my next message from the shitter, nature calls

Lucky for me, I can go in every room in my home without a hitch and get a good or very good reception from my wifi router.


Well, I have since moved to the loo and am picking up a good signal. All works well except that the lighting is dim yellow in the toliet room. A bit pressed for space. Got to love mobile computing.

[GomiGirl]

Got to love mobile computing.

AMEN!!

[Steve Bildermann]

Got to love mobile computing.

AMEN!!

No more religious threads this month please.

[Taro Toporific]

Wired magazine latest issue says the right way to do WiFi is ... Free. "Charging for online usage would be like charging for salt and pepper."
AMEN!!

No more religious threads this month please.

Heathens! Bow down before the Temple of AMEN

[devicenull]

wifi is a requirement of life now... i shudder as i think back to the dark ages of webless trips to the bathroom

hmm, have japanese discovered the joys of crapping while online yet?
do they have a special "bathroom laptop" to go with their slippers?

for the squatters, is there a sort of neck strap so the laptop is able to be used easily?


i lie awake and ponder things like this in the middle of the night

[Caustic Saint]

I'm a WiFi junkie too!

I picked up the Airport card for my iBook in February, and promptly signed up for Korea Telecom's Nespot service (an add-on plan to their DSL plan).They provide a WAP to connect to your DSL modem so you can go wireless as home, and you also have access to any of the Nespot access points anywhere in the country. Most of Seoul is covered and they even put signs in public places identifying these "Nespot Zones." They also have a deal with Lotteria to provide access in all of their Korean locations. The cost for this service? An extra $5 a month.

I agree with the Wired article. For public businesses (restaurants, bookstores, coffee shops) WiFi should be a free service - "value added" if you will. In the US, many companies are signing deals with T-Mobile, Hotspot and a few others. They charge too much (considerably more than free) and use weird billing plans. Since many retail locations have internet access for their business use, why not just upgrade that service to DSL or cable and slap on a WAP?

I played around with my access in Tokyo this spring. I found a couple access points near the Sony building, but the most reliable one I found was the LInux Cafe de Pront in Akihabara. I could hang out outside the cafe and watch shoppers go by while I chatted online.

WiFinder lists 1050 hotspots for Japan and 75 free 802.11.b hotspots in Tokyo. That's a ton more than just 4 months ago. The site lists only 27 hotspots for Korea (all Nespot), which is misleading. True, I don't think there are many free APs there, but there are thousands of Nespot Zones.

[Taro Toporific]

I played around with my access in Tokyo this spring. I found a couple access points near the Sony building, but the most reliable one I found was the LInux Cafe de Pront in Akihabara.

Ueno Station has great WiFi and a free JR Net Cafe too.

[Caustic Saint]

Here's a nice piece from the current issue of Wired about the benefits of offering free wi-fi to customers.

If you want to see the right way to serve wireless access, find a Schlotzsky's Deli. The Austin, Texas-based sandwich chain figured out the secret of making money from Wi-Fi: Give it away. Schlotzsky's lets anyone sign up and use its network free, even if they don't come in for a sandwich. The chain advises its 600 franchise owners to beam Wi-Fi signals through the walls into nearby hotels, parks, and college dorms.

[Taro Toporific]

Here's a nice piece from the current issue of Wired about the benefits of offering free wi-fi to customers.

Here's a good report on availablity...

Want wireless access? Go to Tokyo
BLOOMBERG
Thursday, Sep 11, 2003, Page 12

Intel Corp, the world's biggest computer-chip maker, expects the number of cafes, airports and other areas where consumers can get wireless access to the Internet in Japan to double by December.

The number of so-called hotspots will double to 7,000 by the end of the year from about 3,500