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More Wireless Networking for Linux
I was sent word that AbsoluteValue and Intersil have announced more development of wireless support for Linux. The announcement is actually for Intersil PRISM-based WLAN cards, but what it does mean is more support for IEEE 802.11 wireless cards, access points, etc. Here at Slashdot, we've been using the ZoomAir cards, but are starting to play with the Lucent cards - what does everyone else think about Linux and wireless cards?
The Aviator cards from WebGear are very good. And fairly inexpensive as well. You can get a 2-station kit here. I use them at home and can take my laptop to a friends house and walk right into their network by bouncing dhcpcd. I get about 1.5Mbit inside my house too, which isn't bad considering my internet connection (also wireless) is only 256K.
Having used both Proxim Rangelan II, and several versions of Lucent WaveLan (all pcmcia cards) in linux, I didn't have to many problems.
Neither has full source, you need a binary-only module (or in the case of the proxim driver, a library that you link against, I believe built from the Proxim reference source.) The Proxim driver was a bit bitchy in it's early days, but I'm told it works very well now.
Another note... most wireless LAN solutions have some kind of 'base station' or 'access point' they expect you to buy. If all you have is a few PC's, and it's for the home hacker, you generally do not need this. The cards themselves can communicate with each other just fine. The base station usually serves as the bridge (possibly router) between your wired and wireless networks, sometimes with added features like supporitng multiple transcievers on multiple channels.
Another trick with wireless LAN cards.. if you replace the omnidirectional antenna they give you with a good directional antenna, you can massively extend the range. I have seen Proxim Rangelan II cards bridge distances of about 15 Km and still be within regulations. This also works if you have a wall you need to penetrate that you can't quite manage without. (depends on the materials, though..).
Also.. most wireless LAN cards, by regulation, must use a non-standard connector. Usually, it's a standard connector with the mating parts switched around. (this is to prevent joe average from hookingn his little card up to his linear amplifier and causing WW-III).
Hmm. I could go on for a while.. perhaps I should start a Wireless LAN HAcking FAQ?
Wireless is insanely useful for the portable market. Portable devices that aren't tethered by a cable are becoming more and more prominent in the workplace. The cost however is somewhat justified (note that I said somewhat - read below).
There is a lot of processing power in those little cards to implement the IEEE 802.11 spread spectrum model. They're not cheap for that very reason. Plus you don't have as huge a cable infrastructure, which is a cost most places forget about.
There are on average about 3-4 times as many components/transistors on a wireless card as there are on a comparable network card. You also have to remember that almost all PCI/ISA wireless cards are really a PCMCIA card in a PCMCIA adapter. Compare the cost of a PCMCIA network card to a PCMCIA wireless card and the difference isn't as great as it first seemed.
Why stick with PCMCIA and use adaptors? Well for a start, developing 2 cards in completely different technologies tends to take way too much time, and leads to revision problems. Add to this that the greatest market for wireless is actually portable devices that have PCMCIA slots, and you can see the economics that cause the choice.
However, I'd still like to see a Compact Flash version of these (and using a CF to PCMCIA adaptor, you can still stick with one version), even if it sticks out of the Compact Flash slot. This would bring wireless solutions to devices that could really benefit them. e.g. Cameras - you take a pic, it stores it locally, and then sends it over the wireless link to a box nearby to store it. PDA's - allows you to access network resouces when in range. And so on.
There are also H.323 compliant phones available that use IEEE 802.11 spread spectrum. They operate across your normal wireless network to provide wireless telephony. Now if only the cost would come down, I'd be happy! *sigh*
Anyone who knows anything about this technology knows what Im talking about. First of all, the price. The prices are around $30 for the chipset but it is expected to drop to about $5-$10 once mass production ramps up. This means they will show up everywhere.
So whats so great about bluetooth? Well it was orginally designed to replace irda but it will now be doing so much more. Bluetooth devices have about a 30ft range. When ever one device comes in contact with another, they set up somewhat of a mini network. Eight devices in all can make up one of these networks. One is the master telling the others what frequencies to skip to ect (Bluetooth operates at 2.4ghz and utalizes spread spectrum much like digital phones). These networks can then communicate with other networks of devices. This is all done on the fly and may be reconfigured constantly when new devices move in and out of the area.
So what can be done with this. Well, first the obvious, like networking printers ect but it has so much more potential. From what I hear, the bandwidth is comaprable to dsl which is plenty for most applications and other bluetooth devices dont hog the bandwidth. Well, for one you could could dial up a connection using your phone in your pocket without even touching it. Now imagine bluetooth everywhere and commercial services. Imagine negotiating for an internet connection in an airport without ahving to talk to anyone. Imagine pulic printers, and a slew of other things.
We are only beginning to realize what wireless technology can do. The potential is gigantic. There are some things to worry about like will each device have an id; autonegotiation is scary. 2.4ghz is also the resonate frequency of a water molecule, think leaky microwave. Still, I believe this is going to be amazing, 1) because its so cheap and 2) because its so easy. Truely plug and play networking. Expect to see bluetooth devices this spring and integration into laptops and phones by next fall. For more information, check out Bluetooths home page. Lots and lots of big name backers. This is no vaporware.