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Configuring a Network Connection

Now that you know a little bit about how networks are constructed, it's time to show you how to actually configure your computer to connect to a network and communicate using TCP/IP. It should be somewhat obvious that what you need to configure on your computer is the network interface card (NIC). After you do that, you need to tell that NIC you will be using TCP/IP to communicate. In the old days that required two separate steps. Today, it is assumed that you will want TCP/IP on your network.

Regardless of whether you are using a laptop or a desktop computer, the operating system provides a common graphics-based tool for configuring the network connection. Thus, the operating system buffers you from differences between these two types of computers. The physical differences between a desktop and a laptop computer, however, have a greater impact on your hardware choices for a NIC. That's something that can't be hidden by the operating system!

The following sections explain some of those differences and then show you how to configure a wireless and a wire-based network connection.

Laptop Versus Desktop Computers

Desktop and laptop computers were designed for different purposes. Essentially, the tradeoff can be summarized like this: Are you willing to trade performance for portability? From the perspective of adding network connectivity, you will find that these types of computers are different in terms of your ability to add hardware. However, the logical process for configuring a connection to a LAN is remarkably similar thanks to the fact that both desktop and laptop computers can run the same operating system.

Your challenge in configuring network connectivity begins with determining which type of LAN is best for you: traditional wire-based Ethernet/Fast Ethernet or wireless network. After determining this, you need to figure out how to provide that connectivity on your computer. That last decision is where laptops and desktops can differ.

Laptops

Laptop computers are a bit different from desktop computers because they are specifically designed for mobility. In fact, many aspects of a laptop computer's performance are traded for portability and longer battery life. When you consider that one of the biggest benefits of wireless network technology is how it enables mobility, it isn't much of a surprise to see that virtually all today's laptop manufacturers are including wireless access capabilities as a native feature.

Another implication of a highly portable computer is that the actcarrying itcan be hostile to its innards. Laptop manufacturers know this and go out of their way to make a laptop as durable as possible. What does all that have to do with connecting your laptop to a network? It means you probably can't just crack open the case and start adding internal peripheral devices. If your laptop didn't come with a specific feature, you aren't going to be able to install it yourself. Your only options for add-on functionality are to use an external add-on device that connects via either a USB port or a PC card.

Desktops

Desktop computers are like monuments: They get installed once and stay in that one spot seemingly forever. They don't move around and, generally speaking, can't enjoy the benefits of a wireless connection. Such machines get hard-wired to a wire-based network and stay that way. Given that one of the inherent tradeoffs between wire and wireless is speed versus mobility, it makes sense that desktop computers wouldn't be built with wireless access capabilities. Instead, desktop computers typically are built with 10/100 Mb Ethernet as a native feature. Connecting to a network can be as simple as just plugging in the network cable.

If you want a desktop computer to access a wireless network, you must purchase some type of aftermarket network access device. Two types are on the market. The first is a circuit board that you have to plug into one of the expansion slots on your computer's motherboard.

The second type is external and connects to one of your computer's USB ports. This type of device gets both its electrical power and its network connection over the same wire to your computer. More importantly, you can place the antenna in a spot that enhances its network connection. Because it is an external device, you don't have to install as you would a card on the motherboard. You simply plug it in.

Connecting to a Wire-Based Network

If you are connecting to a wire-based network, chances are you are connecting to either a 10 Mbps or 100 Mbps Fast Ethernet hub or switch. That hub or switch is an external device; you don't need to configure it as far as your computer is concerned.

You do need to configure the NIC that connects to that hub or switch. That's not as daunting a task as you might expect. For one thing, assuming your laptop isn't an antique, the operating system will automatically detect the NIC as well as whether it is actually connected to a network.

The following series of figures from a computer running Microsoft Windows XP shows this.

That's really all there is to configuring and activating a LAN connection on your computer. Getting a wireless connection working is just as easy!

Connecting to a Wireless Network

There are an abundance of acronyms that creep into wireless networking. For the sake of practicality, this exploration is limited to the wireless networks that are most commonly used to support TCP/IP communications. Those wireless networks include the following:

IEEE 802.11a, which is also known as Wireless A

IEEE 802.11b, also known as Wireless B

IEEE 802.11g, better known as Wireless G

The user-friendly aliases ("wireless something") aren't much of an improvement on the official alphabet soup that the Institute of Electrical and Electronics Engineers (IEEE) gives each standard.

Wireless B and G

Wireless B is the older standard established by the IEEE. It operates at 11 Mbps. Wireless G operates at 54 Mbps and is backward-compatible with Wireless B. In other words, if you have a Wireless B laptop and a Wireless G network, that laptop will connect at 11 Mbps even though the network can run at 54 Mbps. If you have a Wireless G laptop and a Wireless B network, that laptop will connect and operate at the 11 Mbps rate of Wireless B, even though the laptop can communicate at much higher speeds.

A subtle implication of this type of interoperability between Wireless B and G is that both use the same radio waves. If Wireless B and G technologies didn't use the same radio waves, a Wireless B laptop wouldn't communicate with a Wireless G network or vice versa. In fact, both Wireless B and G use the 2.4 gigahertz (GHz) frequency range. Interoperability is a simple matter of figuring out how fast each device can talk.

Because both of these wireless technologies communicate at the same radio frequency, both enjoy similar distance limitations. With products conforming to both B and G, you can stay connected to the wireless LAN up to about 100 meters away. Obviously, depending on what lies between you and the wireless network in those intervening 100 meters, your mileage will vary!

Wireless A

Wireless A is a different animal. For one thing, instead of using the 2.4 GHz frequency, it communicates at the 5 GHz range. All by itself, that should tell you that although Wireless B and G can interoperate, Wireless A stands alone!

Wireless A can offer speeds up to 54 Mbps, which is equivalent to the Wireless G standard. Thus, it clearly outperforms Wireless B but offers the same performance as G for a lot more money! For your extra investment, you might be pained to realize that you sacrifice a great deal of distance: Wireless A networks lose signal after about 20 meters compared to the 100 meters of Wireless B and G. That's a function of the radio frequency they use.

Connecting Without Wires

Virtually all the laptops made today come equipped with some form of wireless LAN capability. Using that capability isn't a matter of installing a new featureit is a matter of activating it. No need for PC card add-ons or external plug-ins! You sure won't have to look for a cable interface lurking behind one of the myriad hatches adorning your laptop's sides. You might, however, have to find the physical switch that turns it on.

When you power up your wireless connection, the first thing that device does is seek out wireless networks within its range.

1.	Click the wireless network icon (which looks just like two desktop computers side by side) in the lower-right corner of your screen by the digital clock. This is a circuitous journey! Figure 12-9 shows you the first screen you see upon clicking that wireless LAN icon in the status bar. Figure 12-9. Seeking Out Wireless LANs This screen offers a lot useful information. First of all, it confirms whether you are actually connected to the network. Next, it lists the signal strength (good, in this case) and the speed with which are you connected to the wireless LAN. This screen also tracks how many bytes you have sent and received since that session became active. Notice that the laptop, even though of recent manufacture, only connected at 11 Mbps. That would indicate that the connection uses the IEEE 802.11 B standard instead of the more robust G standard. Clicking the Properties button on that screen brings up the aptly named General Wireless Network Connection Properties. That screen is illustrated in Figure 12-10. Figure 12-10. General Wireless Network Connection Properties As was the case with wire-based Ethernet, the operating system assumes that you are using TCP/IP to communicate across that network interface. It is already selected for you.
2.	More information is available about your wireless LAN connection by clicking the Wireless Networks tab at the top of the screen. This screen shows you how many wireless networks your computer is able to access. That screen is shown in Figure 12-11. Figure 12-11. Wireless Network Connection Properties Figure 12-11 shows you a laptop, when operated from home, only finds one wireless network. Fortunately, that's the correct network! It is given the rather unimaginative name of linksys in honor of the hardware's manufacturer. Go ahead and laugh for the unimaginative network name. Then think for a minute about how much information you would like to give away to anyone within radio range of your home network. Perhaps a generic name isn't so bad after all! Assuming that your wireless network itself was configured properly, you should change two things about the default settings that Microsoft uses for wireless LANs. Both help to better secure your laptop and any data you might be transmitting. The first step is to enable your computer's firewall. Although a poor substitute for an industrial strength firewall, Microsoft's free version is better than nothing.
3.	Click the Advanced tab at the top of the screen. (Do not click the Advanced button at the bottom of the screen.) Figure 12-12 shows you the screen you get when you do this properly. Figure 12-12. Enabling Your Computer's Firewall for Wireless Connectivity
4.	All you need to do to activate the firewall is check the box! That protects you from most unwanted intrusions from the Internet. The next thing you want to do is to protect the data that you are sending and receiving across the radio waves. You can do that by encrypting the data that you are sending and receiving between your computer and wireless network.
5.	When you are at the Wireless Network Connection Properties box, click the Configure button. That brings up the Wireless Network Connection Properties screen.
6.	Check the box that says Data Encryption (WEP Enabled) and you are done! Figure 12-13 shows you this screen with that box selected. Figure 12-13. Encrypting Your Computer's Data Transmissions

For wireless encryption to be activated, it must be enabled at both ends: the computer and the radio access point. This section assumes that the access point was already configured and just shows you how to configure your computer.

That really is all there is to it. By following these simple steps, you can configure and secure a wireless network connection.