|
Related Articles: |
Wireless communications via cel phones and PDAs are generating lots of interest among technophiles, and rightly so -- they're terrific. But diminutive screen dimensions and low-octane processing power limit the capacity of these devices to accomplish many of our everyday tasks. For the time being, most of us still need notebooks and desktop computers to get the work done.
Thanks to technology developed by Lucent and other companies, however, our draft horse computers no longer need to be harnessed to the closest RJ-45 wall outlet. We can roam freely throughout the spacious interiors of our homes and offices happily connected to the Internet or to our nearby co-workers.
Am I talking about some sort of fumbly, bumbly, cumbersome technology that takes more time to implement than time saved using it? Absolutely not. Are we looking at leveraging our credit cards to replace aging wired networks with wireless freedom? No way.
Owners of current Macintosh computers can set up a wireless network right now for less than $200 US and one hour's worth of set-up time. I know because I just did it, and I'm never going back to running cable through my walls, under my carpet, and over my doorways. The wireless office is here right now.
Apple's branding of the wireless network is called "Airport." If you have one of the new "slot loading" iMacs (selling for as little as $995 USD), iBooks ($1,599 USD), or PowerBook 2000s (beginning at $2,499 USD), your computer has a built-in antenna, Airport card slot, and compatible system software for wireless communication.
Airport cards sell for $99 USD each and can be installed in about 15 minutes. Don't worry about making an appointment with your local hardware repair technician; anyone who can read a few paragraphs of instructions and can keep from shuffling their feet on the carpet can install these cards.
If you plan on creating a "roaming" network in a large facility, or want to have many users on your LAN, you should consider one or more Airport Base Stations selling for $300 USD each. However, if you have an iMac already connected to the Internet, and want to wander about the office with a couple of laptops, then you can bypass the hardware Base Station (often referred to as the "spaceship") and designate your iMac to be a "software" Base Station.
The most compelling reason to purchase the $300 spaceships is if you have a large facility and want to enable active roaming throughout the building. Generally speaking, the effective range of communication is limited to 150 feet (45 meters) per hub. In most cases that's enough. But in a more spacious setting, such as a school, that effective range can be extended by strategically placing spaceships throughout the facility and configuring them for active roaming.
Essentially, active roaming works when you give all of the spaceships the same name and connect them to the same subnet on your Ethernet network. Also remember to use just one password for all of the hubs. Once configured, client machines can wander from zone to zone maintaining communications with the strongest signal in that particular area. For these applications, a dedicated, compact, $300 spaceship makes more sense than a larger, more expensive $1,000 iMac.
But why spend the $300 bucks if you don't need to? Most home offices can simply designate an Internet-connected iMac or PowerBook to act as a Base Station. Remember to set the "Energy Saver" settings to "never sleep" on Macs serving as Base Stations.
You can continue to use your Internet-connected Mac normally as it transmits to other computers across the wireless LAN. I've notice little, if any, degradation of performance during transmission.
Once you've configured your software Base Station, any computer on the network requiring an Internet connection will prompt the Base Station to establish a connection via the dial-up, DSL, or cable modem. The Base Station's Internet connection is then made available to the other clients via DHCP. Current software Base Stations don't support static IP addresses for client Macs.
This scenario can be particularly appealing to home networks where family members fight over a single Internet connection. By creating the Airport wireless LAN, each client can access the Web via his or her computer -- even while others are doing so. That will certainly make the kids happy.
|
You may be wondering how much speed you have to sacrifice in order to gain portability. You'll be happy to hear that the Airport wireless network can transfer data up to 11 megabits per second (Mbps). The software interface includes a nifty "signal level" indicator that shows you the strength of your connection. In my home environment, it averages 80 to 90 percent of the maximum 11 Mbps.
Since Airport sends information via radio waves, there's always the possibility of signal interference. Base stations have 10 channels to choose from if interference becomes an issue. Devices that can cause interference include microwave ovens, 2.4 gigahertz phones, and RF leakage from direct satellite service.
Also keep in mind that some building materials can affect Airport communication. Typically, wood, plaster, and glass have very little impact on Airport communication. On the other hand, concrete and metal will most likely degrade performance. Bricks and marble fall somewhere in between.
One final word of advice: don't use the Airport card in an airport or on a plane. If the airlines are concerned about interference from a portable CD player, imagine their views on radio frequencies broadcasting up to 150 feet!
Apple uses the "silver" version of the Lucent communications card which adheres to the 802.11 cross-platform standard and has 40-bit encryption. You can create an additional level of security on your wireless network (called Access Control) by only allowing computers with specific IDs to log on. Each Airport card has a unique ID number stamped on the outside. By listing the ID numbers of the computers that you will allow on your network, you can control participation. Access Control can handle up to 497 client computers.
If you don't know your Airport ID number, don't worry. Simply launch the Airport application and click the button reading "Turn Airport On." Once Airport is activated, you can read your 12-digit alphanumeric ID in the status area.
Taking a page out of the Napster/Freenet book of philosophy, Airport-enabled computers can communicate directly with each other even when they're away from a Base Station. Apple calls it a computer-to-computer connection.
This function is especially handy for setting up a multiplayer game network or for encrypted file sharing. Not that anyone ever attends a boring company meeting, but if one did occur, Mac-toting attendees could spontaneously set up a network and exchange notes or play a game to pass the time.
To do so, both parties simply set their Airport configuration to "computer-to-computer." Each active computer appears by name in the Airport control screen, and the connection is activated by simply choosing the computer you want to engage.
Internet connections via Airport require standard Internet protocols such as PPP. This is fine for most users. The most likely exception to standard protocol would be logging on via America Online, which uses non-standard access. Also, some DSL providers use PPoE protocol which can also cause Airport connection problems. It's best to check with your ISP before purchasing Airport hardware.
Because Airport uses cross-platform standard 802.11 protocol, a Windows/Mac wireless network is possible -- at least in theory. We're going to try to establish just such a network at O'Reilly. Our next article will report the outcome and delineate the procedure -- if we can make it work.
In the meantime, Mac users who have Airport-enabled machines might want to consider setting up a wireless LAN. There's nothing quite like taking your PowerBook out to the patio on a beautiful day to finish up that last bit of e-mail correspondence. You'll be the envy of everyone in the office.
Derrick Story is the author of The Photoshop CS4 Companion for Photographers, The Digital Photography Companion, and Digital Photography Hacks, and coauthor of iPhoto: The Missing Manual, with David Pogue. You can follow him on Twitter or visit www.thedigitalstory.com.
Discuss this article in the O'Reilly Network Wireless Forum.
Return to the Wireless DevCenter.
Copyright © 2009 O'Reilly Media, Inc.