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Ah, Philadelphia, my home town. I went to attend one of the 80211-planet.com Wi-Fi shows there a few years ago. The conf was pretty small compared to all of the other shows I've been to. Thank goodness that's changed. We did quite a bit of wardriving, a snipplet of which you can see here. Since then, Wi-Fi coverage has exploded, which you can see here and for your area.

Of course, the pansy-assed white folks there can't cook, there are still a few places to get a decent meal.

I had a fun time wardriving with Lord Hector and Umut after the 80211-planet.com in Philadelphia a while back. Wardriving is definitely a neat way to explore a new City (or even one's home town). We have the data we collected posted at WiFiMaps.com.

This isn't something that's likely to become a serious exploit, for the simple reason that the attacker would need to bring a compatible device within range of the access point. Unless someone has a serious grudge against the owner of the network, who'd want to spend the time? You'd either have to be present with a laptop/pda, or leave it behind. Remember, we are talking about radio waves here. Plenty of technology exists to track 802.11x signals, and all it takes is a well equipped sysadmin and a properly filed lawsuit to discourage the attacker.

If you notice in the image, the program is set to 2.4GHz (the frequency at which 802.11b wireless operates), but it looks like the frequency is changeable. What I find interesting is that it picks up the frequency on 2400MHz, when in fact, channel 1 of the 802.11b starts at 2412MHz (here for more info) and channels above that step up in frequency. Scenario: my neighbor John has a linksys wireless router set to its default channel 6, and I set my wireless device(s) to channel 11. Since this cellphone detects (at least, assuming they were using channel 1) within 12 MHz, what are the chances I can test just the strength of MY network? It seems as though the idea is good, but in an inner-city area, where wireless networks are more popular, it looks like it would be harder to really test your own network.

>detail any downsides of using the 5Ghz band?

I'm no radio geek but...

As a rule of thumb the higher the frequency the shorter the range. Range and wall penetration are going to be much more important factors than thoroughput for almost all residental installs and many business applications. I believe the current estimate is you'll get 1/4 the range. Err, no thanks.

Its not exactly that simple. At the same distance 802.11a outperforms b. So if, and this is a big if, an 'a' client and a 'b' client are both at 175 feet or so then 'b' will get 2mbs and 'a' will get 6mbs.

What I think is starting to happen, that is if everyone doesn't just switch to a/b/g multicards, is that 'a' has a better chance of getting business sales. Businesses can afford to put up more APs to handle the range problems and could really use the extra bandwidth.

Home users will probably stick to 'a' (or 'g') as its range and penetration is a big plus. Bandwidth isn't much of a consideration when 99% of these users will just be connecting to a slow WAN pipe like a DSL line or a cable modem.

Neat little comparision chart here.

WPA will replace WEP as the standard 802.11x encryption scheme. It fixes the major problems with WEP e.g. airsnort won't crack keys anymore, and the implementation is supposedly easeir to use than WEP.

The bad part is its no IPSec w/ 3DES, but its better than WEP and many manufacturers will be able to provice WPA by ugrading the firmware on the card and access point, depending on the model of course.

I believe Windows XP support is already here.

From a single key? No. To brute-force crack WEP, you either need a few million packets to work with, or, you monitor passively and basically let it do the work for you. The more packets you have at your disposal to compare, the less time its going to take.

The whitepaper I read regarding WEP encryption vulnerabilities is the same one i'd imagine everyone else has read. There are a couple of approaches to it, but generally speaking, successful WEP cracking (IIRC) takes upwards of 5-8 million packets, minimum...Basically, enough packets to ensure than a weak IV will be found. Short work from there.

5-8 million may seem like alot, but on a busy network, it's a drop in the bucket. It can be broken within hours.

Have a look..A good article awaits you. :)

It depends on what the gain and such is of the antenna. With an omni, maybe, but with a wave-guide cantenna you are probably safe.

See here for details

Besides, I think this is definately more doable that hands across america. With the possible exception of the rockies/cascades etc, just set up some cantenna's, and aim it off into the horizon. With GPS and such, it should be easy to coordinate. A handful of people at each horizon, should do it... How far away is the horizon anyways? I know I can see the buildings in downtown from here, and its like 20 miles from here.

Yes, because we all know that there are no interference problems between 802.11, 2.4 GHz phones, and microwaves.

Frankly, the 2.4GHz spectrum is a case in point of why regulation is needed.

I agree that this is absolutely necessary, as I pay the bandwidth bills at my company and know what it's like, but they have to be careful not to stifle innovation, as the security features they will now need become more and more complicated.

What will this do to the thousands of students that use 802.11b at the library and other campus buildings? Will the charges be based on MAC address? Since MAC addresses are so easy to spoof, authentication will become necessary. How can that be done easily across multiple platforms?

The new measures might wind up costing them more than they expected. How about limiting speed by user? That would not get in the way of most legitimate research, but it would render P2P movie sharing useless.

I think the link you want to post was this:

http://www.80211-planet.com/news/article.php/15847 61

cheers from S-pain

You talking about WEP? a gig of captured data and it's cracked.

You are right about WEP. The thing is that nobody said anything about WEP so I would imagine that they are not using it since it is well known to be easily compromised. I would place my bet on them using either TKIP (better than WEP but not best) or AES. The problem is that I think AES is in the 802.11i spec not 802.11b. I wonder if they are really going to use 802.11b as the article states or if it is a proprietary 802.11x implementation?

Note: This article is a really good primer on 802.1x excryption techniques. They state that AES is now a Federal Information Processing Standard, FIPS Publication 197, that defines a cryptographic algorithm for use by U.S. Government organizations to protect sensitive, unclassified information. The Secretary of Commerce approved the adoption of AES as an official Government standard in May 2002.

So no, WEP is not likely.

Why-do-I-care panders: The other day, Some Guy took his radical casemod out for a bit of 802.11 action at 36,000 feet. That's amazing, beats the onboard movie.

This is FUD generated by the DOD. The FCC limits the EIRP (equivalent isotropically radiated power) of the ISM band used by 802.11. The allowable power levels for 802.11 are 1 watt using an omni-directional antenna and 4 watts for a directional antenna. I doubt the tinny amount of power these devices emitted will interfere with military radar. For more info about 802.11 power levels check out this 802.11 Planet article.

Is there any introductory reads about all the different 802.11's? it seems that we now have a b c d e f g.

Google and ye shall receive.

One more question for the grou: I have read a lot (for a Business Analyst) about wireless networking and have yet to see a place which explains the "lettering system" used by the 802.11 products. Why are a, b, and g given those names? Are there 802.11c and d awaiting consideration?

Do a Google search and you'll get the answer. 802.11d is a set of protocol addons to 802.11b to enable it to work where 802.11b is illegal, for example. More info here.

Here is a nice comparison of B and A on 80211 planet. Also, a whitepaper for A is available at Proxim Communications. Also, don't forget the FAQ!

My personal feeling about this: The U.S. government should sponsor a 802.11a nationwide network, so we can all have cell phone and data access anywhere, and a provider can 'buy' an area from the government to charge wireless rates for. Kind of like the current system we have in place for land-line phones.

Everyone comes out happy:
the cell phone company has a local monopoly
the customer has access to wireless data and phone everywhere
the government 's pocket gets fatter.

All of the hardware is based on Intersil's Prism2 chipset, which means that the Linux Prism2 drivers will work on the MSFT cards. Check out this article. Microsoft's page is here.

IMHO this article seems less-than-clueful.

About 1/5 of it is devoted to the idea of making more bandwidth at 2.4GHz through the magic of "spread spectrum". "Wi-Fi" (and as far as I know, no one who actually understands 802.11b calls it Wi-Fi) has always been spread spectrum. The technological advance they seem actually to be talking about is automated bandwidth allocation. (Call me when my "cognitive radio" is ready.)

The article also seems to have no clue about the higher-frequency bands used by 802.11a, that are so far pretty empty, or about the more efficient use of spectrum with 802.11g. Either of these things could make a huge difference in 802.11 bandwidth availability in the short term.

Indeed, the authors seem to have some kind of corporate want-to-see-it-fail axe to grind. Consider the introduction. IMHO that Doonesbury cartoon was as non-insightful as most of Trudeau's recent comments on bits and ownership in the digital age. (Hint: he's a cartoonist. He's one of my favorites in general, but on certain subjects, his job gives him a vested interest.) If I'm paying flat-rate, as many folks are, I could care less who borrows my unused 802.11 and net connection bandwidth: it's not hurting me an iota. As far as I'm concerned, anyone who feels otherwise should review their social contract carefully.

In sum, I think there are far better places to get your Wi-Fi report than the referenced article.

These companies use central servers with satellite net appliances behind the access point to control user access and in some cases bandwidth provisioning for user groups. Roving Planet also has bandwidth provisioning for specific applicaitons.

This is your ammunition when users come and ask
why the wireless network is slower than the wired network with fewer users (preventing contention adds more overhead in wireless)

The right answer is: wireless networks are just plain slower than wired ones. Wired networks claim 100Mb/s access and wireless ones claim ~1/10 of that at 11Mb/s.

Actually CSMACA (as opposed to CSMACD the medium contention handling mechanism wired 802.3 networks use) really plays only a small part in the speed of .11 networks. It's the format of .11 physical layer packets and quality of current PHY layer chips which limits the throughput of most solutions to around 4 Mb/s.

New cards coming out from US Robitics using TI 802.11 silicon get consistent throughput close to 7Mb/s. Linksys also uses the TI ACX100 chipset, but doesn't have quite the marketing machine USR does.

If you need more speed you ought to check them out. Still not like a wired network but a hell of a lot better than 4 Mb/s.

What if a new wireless local loop technology was deployed by Qwest (or whoever) that just happened to interfere with Wi-Fi? What if XM radio takes off and becomes the norm? According to the FCC the 2.4Ghz band is fair game.

We really need to work on ways to transmit data over
a constantly changing sea of background noise.

Adaptibility and fault tolerence are needed.
I'm picturing something like the ever-slinky P2P networks.
Kill a node and the network lives on.

Intelligent re-routing of data around "trouble spots" on many different carrier types.
A pipe dream for now, but with things like UltraWideBand
in the works it may not be for too much longer!

it was reported last week in other places.

The backwards compatibility problem has not been solved yet for the legacy 802.11b systems to inter-operate with 802.11g. Until that happens, 802.11a, despite its problems with permeating substances such as brick and other building materials, is still the better alternative.

This new higher speed for 802.11b mentioned in the article gives buisnesses NOW the opprotunity to upgrade their current hardware without installing a brand new system to operate in the 5ghz range.

Some interesting comparisons of 802.11a, b, g and the various combinations thereof that are kicking around: Clarity & Understanding: The High-speed WLAN standards debate

In the summer of 2001, Rob Flickenger, a network administrator, published plans for converting a used Pringles container into a directional antenna costing $5 a piece with a 10 mile range. From there, free 802.11 networks shared plans for broadcasting with coffee, soup, pasta -- even 40-ounce beef stew 'cantennas.'

Sputnik is actually an open-source architecture and Joltage is closed source. As for the need for both of these services, there isn't any. They both violate Acceptable Use Policies for most, if not all ISPs. Using one of these services to freely distribute bandwidth to your surrounding neighbors would certainly be more preferrible, than selling it. Since there are even more legal issues concerning selling bandwidth, especially for a home user.

Here's an article at about the two services.

Most likely, you just haven't had enought time to play with 802.11b. Once you do, it is a cakewalk, and proably the best money I have spent on computer equipment since my first modem (2400baud).

head over to 802.11 Planet and look at their tutorials to get started.

there is nothing like surfing on your ibook from your couch, playing an mp3 in the background streaming from your linux box. i leave my inernet connection wide open 1) because I want people to use it. My internal network is protected behind a good firewall, but anyone in the area can have internet access. and 2) i think it's the right thing to do to help the community. think if everyone shared their connection. it would make the world a much better place.

If you dig PR, then head to 802.11 Planet. You'll get all the corporate lubing you could ever hope for.

802.11a is not new, it's been around since 1999. Check the IEEE website. They have the document available for free download.

It may not be a necessity for your slow internet connection, but at these speeds you'll be able to have things like wireless video servers and other fun things. You'll ultimately be able to carry your info/entertainment appliances around anywhere in your house and wirelessly access the equipment that serves them. I've had to crawl under my house many times to snake the various cables around down there, and it's a real pain. Particularly so when I reconfigure a room and now the wiring is in the wrong place. In the future, you'll just move the television, computer, or whatever to its new location, and there you are.

As for range, this article says, "We carried the workstation around our offices with some freedom within a range of 75 feet or so with no deterioration in quality until very substantial impediments (heavy concrete walls) interrupted the signal."

A 75 ft distance would be more than enough for most homes, if the WAP were in the center.

Acording to this article on 80211 planet You should be able to get 3x the speed at the same distance you get from an 802.11b card.

Acording to this article on 80211 planet You should be able to get 3x the speed at the same distance you get from an 802.11b card.

Here is the correct link:

(damnit, i have to type more text than HTML tag to get past the lameness filter Argh!!)

802.11a 54-100Mb/sec