This article appeared in the September 2002 WYSIWYG newsletter.
Going Wireless
by Rick Schummer
There has been much press in the computer trade magazines and on the news about wireless connectivity. Many consumers hear "wireless" and immediately think about cell phones, some think about personal digital assistants (PDA), and some think about connecting a network of computers with a wireless local area network. This article will focus on the wireless local area network, and in general what it takes to get computers to talk to each other without copper cables using the Wireless Ethernet Compatibility Alliance (WECA) wireless fidelity (Wi-Fi) standard.
Four months ago our company decided to lease office space in an old mansion in Detroit. We lease much of the third floor and the biggest issue the landlord noted is that he did not want us to alter the walls in any way. These walls are covered with old woodwork and they did not want a bunch of geeks cutting holes and dragging cable. We also did not want cable hanging along the floor ready to trip employees or customers. Our solution was to go wireless.
What you need
So we went to the computer store and purchased 5 wireless cards and a wireless access point (WAP). There are a number of brands and models. It is outside the scope to compare all of these. I will mention that at home I have a Linksys Ethernet WAP with a built in Cable/DSL Router, and 4 port switch. What this means is that I can connect my DSL line into the router portion (bypassing the ISP router), connect up to four computers to the network with copper Ethernet cables, and all share access to the internet. Additionally I can connect to another hub which connects more computers via Ethernet cable. This demonstrates that you can ease into the technology without converting all the network connections all at one time. The WAP will additionally support 256 computers (how practical this is I am unsure), definitely enough for homes and small offices.
You need to install the wireless card in the desktop or notebook computer. The card you buy will depend on your configuration and the type of slots available (or sometimes more importantly, what is not available). Notebook computers must have a PCMCIA slot free. Desktops can get normal network type cards with wireless capability via a built in antenna. Some desktop wireless cards have a PCMCIA slot built in, which requires you to purchase a notebook wireless card. So buyer beware, do your research. As far as the wireless access point, again it depends on your needs. If you already have a network set up, you might just need a plain old WAP, nothing fancy. If you are just starting out and need to connect other computers with various network cards performing at different speeds, you might need a switch built in. If you are like me and wanted to have other computers to share one Internet connection, you might research the DSL/Cable router feature as well. There are drivers to be loaded so the operating system can communicate with the new device. I have found Windows XP to be a true joy with this technology. It understands wireless networking. Other OSes will also work, but check for compatibility issues. My only experience is with Windows 2000 and Windows XP (the easier of the two).
One thing I can definitely say about Linksys is that they provide nice diagrams on the boxes of their products. It diagrams the capabilities so people like me who know little about the inner workings of this hardware can see what they need. Naturally it also recommends their hardware, but even if you do not buy Linksys, it gives you an excellent idea of what you might need. If you are confused, hire a professional to help you out, or maybe you can find an expert in the user group that can assist you (that would not be me).
How it works
I am not an electric engineer or computer engineer, so I will not get to deep into discussing how this works. The WAP sends out a signal just like your wireless phone does from the base station. All the WAPs I have seen have two antennas that send out the signal. This creates a bubble around the WAP (depending on how you point the antenna). This bubble can range from 30 to 90 meters indoors and from 150 to 450 meters outdoors with a standard WAP. The signal strength degrades the further you get from the WAP. The signal is transmitted over the airwaves on the 2.4-gigahertz (GHz) frequency which is the same frequency as some wireless phones and some microwave ovens. The computer and the wireless network card look for that signal. They connect and the rest works just like being connected with copper wires.
Just so you know, there are a number of wireless standards. The most common is the IEEE 802.11 standard. Within this standard are a number of substandards. The most popular one is 802.11b. Under 802.11b, devices communicate at a speed of 11 Mbps whenever possible. If signal strength or interference is disrupting data, the devices will drop back to 5.5 Mbps, then 2 Mbps and finally down to 1 Mbps. Though it may occasionally slow down, this keeps the network stable and very reliable. Distance does make a difference. In the home arena, you will likely get 11Mbps almost everywhere, unless you run into some interference. In our office we have the wireless networking and a phone system that work on 2.4Ghz and they co-exist with no problem.
You configure the WAP via a web browser by browsing a TCP/IP address (ie http://192.168.1.254). Minimally you will need to configure the ESSID (the name you give your network). This is what is broadcasted to wireless enabled computers. I also recommend enabling WEP security (see disadvantage section later in this article). Depending on your ISP and broadband capability, you might have to configure the login to the ISP to make the connection. That is all. The setup literally took me 30 minutes because I read the instructions. Your mileage might vary.
Advantages
I can literally use my computer and be hooked up to the network to get email, surf the web, and copy files to and from other machines. I can do this from anywhere in the house, in the yard, and even down the street (although the signal gets weaker and performance goes down the farther you get away from the WAP). If you are using Windows XP (the OS I use on my main machine) it auto detects the wireless card and the wireless network as I get in range of a WAP (see security issues under disadvantages).
No more need to fish a line through the walls of my house or office. If our customers have this technology installed I can literally walk into their offices and be on the network without having to search down a wire. This can be important if you have a multi-level home or in a college dorm, or any place that is not conducive to dropping wire.
There are also a number of "hot spots" being developed in major cities that allow mobile computer users to connect to public networks in coffee shops, restaurants, college campuses, and public buildings like libraries. There are even private companies making wireless networks available to people who get inside their bubble.
Disadvantages
In my case, the network maxes out at 11Mbps which is nine times slower than wire networks running at 100Mbps. If you use a 10Mbps network, it is obviously faster. The performance is only really noticeable when copying files between computers (which is how I do backups). It does not slow down even the fastest access to the internet since cable modems and DSL typically max out at 1.5Mbps. When I need the higher performance I plug in the wire.
There is a security exposure that is available with a WAP if you do not use encryption. With a wired network, only those plugged in can access the network, the computers, and the Internet connection. Wireless users can literally see any wireless network that they bump into. This means anyone inside the bubble can possibly have access to your computer, other computers on the network and Internet connection. There are a number of ways to lock others out. The Wired Equivalent Privacy (WEP) makes sure that only users with a key can access the network. This is the simplest way to lock others out. You generate a key that each computer needs to have in the wireless connection. It is simple to enter in because you are prompted the first time you connect to the WAP, although it is a long string of letters and numbers. For stronger techies, you can also specify specific computers via network card MAC addresses. I also highly recommend setting the administrative password on the WAP to something other than the default so someone cannot hack their way in and change your settings. All this is well documented in the user manual and is easy to set up. Some WAPs have the ability to enable firewall protection. Mine had the ability to license ZoneAlarm Pro and PC-Cillin for anti-virus.
New standards are evolving all the time. The 802.11a is available which improves the speed even though the letter on the standard went backward from "b" to "a" (they never make this easy do they). Jumping in now means that you might have to purchase new WAPs and cards later to get the better performance. If this is important, I suggest you hang out on the sideline a little longer.
The last disadvantage is that I have experienced that occasionally the WAP will lose its mind, and you will lose your connection. Overall I have found the network to be very reliable, with only minor glitches.
Other resourceshttp://www.howstuffworks.com/home-network.htm http://www.howstuffworks.com/wireless-internet.htm http://www.linksys.com/
Conclusion
I have been really impressed with this technology even though it really is considered to be in the infancy stage. I also expect it to be improved rapidly over time like the rest of technology.
End of Article