Wireless networking is hotter than ever today, thanks to falling pricing, better security, and a new generation of products that have been engineered for simplicity and ease of use. If you’ve held off from adding a wireless network to your home, home office, or small business, it's time to reevaluate that decision.
A wireless network is any network in which two or more computers can communicate wirelessly. You can configure a wireless-only network or a more versatile network in which some computers are connected via Ethernet cabling (which is generally faster than wireless) and some are connected wirelessly (which is more convenient and mobile than Ethernet). For the purposes of this discussion, wireless networking refers to Wi-Fi (“wireless fidelity”) technologies, such as 802.11b and 802.11g, and not competing and complementary technologies such as Bluetooth, infra-red (IR), and so on.
Wi-Fi networks are growing in popularity both within private homes and offices, and in public areas such as libraries, cafes, schools, airports, and other places. That's because Wi-Fi is a well-established wireless standard, with full support from major OSs such as Windows XP, Mac OS X, and Linux, and from the major networking hardware makers. In a home or home office, wireless-equipped notebook computers and Tablet PCs can be used virtually anywhere in the home, and even in the yard, depending on the size of the building and the placement of wireless hardware (we'll discuss this in more detail below). The resulting freedom can be liberating: Imagine answering email over breakfast from the kitchen, or browsing the Web from bed, and you'll get the idea. Once your PC is no longer tethered to a cable, your computing experience becomes more personal and enjoyable.
Wireless is also inexpensive. To correctly wire a home for Ethernet would require a serious commitment of time, effort, and cost. Wireless networks, meanwhile, can be created quickly and cheaply, without any need for starting a construction project. Wireless is also highly flexible. If you already have a wired Ethernet network in your home office, for example, you can simply add a wireless access point (AP) to your existing network; computers in the office could continue to use the wired network, whereas mobile computers and PCs in other parts of your home could be connected wirelessly.
Today, the most popular wireless standard is 802.11b, an 11Mbps shared bandwidth solution. But despite its bandwidth rating, 802.11b networks are almost always quite a bit slower than 11Mbps networks, averaging instead about 4Mbps to 5Mbps or less bandwidth with many users. Distance is also a factor: As you move further away from a Wi-Fi wireless AP, or pass behind obstructions, your signal to the AP's radio becomes weaker, lowering your bandwidth. This situation affects all wireless networks, but it's particularly acute on an 802.11b network because of the slow speed of the network even in a best-case scenario.
That said, 802.11b is fine for many tasks, including email, Web browsing, light file sharing, streaming music, printer sharing, and so on. But 802.11b becomes less viable when heavy file sharing, video streaming, game playing, or other high bandwidth tasks are required.
Several competing standards emerged to supplant 802.11b, but it’s now clear that 802.11g, or Wireless-G as it’s often called, will be the winner. Wireless-G runs at 54Mbps (about 20Mbps to 25Mbps in the real world), offering about 5 times the performance of 802.11b. Best of all, Wireless-G is backward-compatible with 802.11b, meaning that Wireless-G and 802.11b hardware can interoperate. There are issues with this, however: A Wireless-G networking adapter can connect to an 802.11b network only at that network’s 11Mbps speeds. And if you use an 802.11b-equipped device to access a Wireless-G network, the effective bandwidth for all users--including those with Wireless-G cards--drops to just 11Mbps.
To counter this problem, some Wireless-G hardware includes a feature that locks out 802.11b hardware, ensuring that the wireless network runs only at the fastest possible speed. This is a great solution if backward compatibility isn’t an issue.
Setting Up a Basic Home Network
Although you can connect two or more computers wirelessly without sharing an Internet connection, let’s assume that part of the reason you want a network at all is to share a broadband Internet connection. Most broadband connections in the US are obtained through cable, telephone, or satellite communications companies, and although the specific details can vary, each of these technologies involves a modem of some sort, such as a cable modem or DSL modem. This device connects to the outside world through a coaxial cable, and will typically supply 300Kbps to 3Mbps of connection speed. The modem connects to your PC or home network through Ethernet cabling or a similar technology; some modems use a USB connection, for example.
If you have only one PC, the Ethernet cable from the cable or DSL modem will connect directly to an Ethernet port on your PC, and you’re good to go: Simply boot up the PC and you should be online. To create a home network, you need to add a middle-man device, called a router, between the cable modem and your PC. A router typically includes one wide area network (WAN) Ethernet port, which you might think of as the OUT port. This port connects to the cable modem. It will also include one or more local area network (LAN) Ethernet ports, for adding one or more PCs to the home network. In the single PC example used above, you would plug the Ethernet cable from the cable modem into the router’s WAN port and string another Ethernet cable between a LAN port on the router and your PC’s Ethernet port.
If the wiring is correct, you should be able to turn on your PC and be online. But a not-so-subtle difference exists between a direct connection from a PC to a cable modem and the simple home network I’ve described. To access the Internet in the direct connect model, your Internet access provider (the cable, telephone, or satellite company) must give you an Internet protocol (IP) address, a unique identifier that takes the form of 123.456.789.012. This address could be static (meaning it never changes) or dynamic, which means the access provider is using a dynamic host configuration protocol (DHCP) server to assign you a (relatively) random IP address each time you turn your computer on and connects for the first time. Either way, your IP address is your face to the Internet, and a way in which remote hosts can uniquely identify you.
When you add a router to the mix, your access provider assigns an IP address to the router and not to your PC. The access provider uses this approach because you usually can have only one IP address per Internet connection (although some access providers accommodate more). But in a home network, you probably want to let two or more machines access the Internet simultaneously, and you don’t want to have each machine kick the other offline every time it loads a Web page. To get around this problem, routers support a technology called Network Address Translation (NAT), through which the device presents a single IP address to the outside world, but supplies machines on the home network unique internet IP addresses. The router literally translates requests from the outside world and routes them to the correct PC as needed. This approach lets you share your Internet connection among two or more PCs. And, as you might expect, the router also includes a mini DHCP server of its own so that it can hand out IP addresses just as your access provider does.
Well, not exactly. The router’s DHCP server is usually configured to work with special ranges of IP addresses that are reserved for private use. These IPs usually start with 192.168, although other ranges are available as well (a typical private IP address is 192.168.0.23, for example).
If you have only one PC, adding a router to the mix won’t change your life much. But if the router has two or more LAN ports, you can easily add more PCs to your new home network. And that’s when things get interesting: Not only can you share an Internet connection now, but you can also share files, printers, and other network resources. We'll look at some of these uses below, but first a burning question remains: How do we add wireless access to our home network?
Adding Wireless Access to the Network
Depending on the type of router you purchase, you might need to add wireless access separately. However, most network routers sold today include an integrated wireless access point, and as such, they are often marketed under different names. For example, you might see networking products called base stations; these are typically devices that combine router and wireless AP functionality in a single box, offering both Ethernet and wireless access to the Internet and local network.
If you’ve already implemented wired networks, many networking hardware makers now offer dedicated wireless AP devices that you can add to your existing network. But if you’re starting today, get a base station and save yourself some complexity. With either approach, the router and wireless AP are logically, if not physically, separate items. Even in an integrated base station, you can think of these components as separate devices.
To add a wireless AP to an existing wired network, simply use an Ethernet cable to plug in the device to one of the LAN ports on your router. (Users with integrated devices can skip this step.) Then, use your device manufacturer’s instructions to configure the wireless AP and install wireless adapters on each of the machines that will access the network wirelessly. The specific instructions will vary by device, but connecting an AP to an existing wired network will likely be a simple task, especially in Windows XP or Mac OS X.
Securing the Network
One aspect of wireless networking that you shouldn’t take for granted is security. Most of the wireless networks set up in homes are unsecured, open to attack from the outside world. The reasons for this sad state of affairs are somewhat complex. First, many home users don’t realize that wireless technology is inherently unsecure and that hackers with wireless “sniffers” could access their home network from a car on the street outside their home by using a wireless-equipped notebook computer. Second, even when users understand the risks, wireless security has been fairly hard to implement, causing many people to simply give up and leave their networks open. The original 802.11b wireless security standard, Wired Equivalency Protocol (WEP), was somewhat of a joke in security circles, and dedicated hackers can break it fairly easily. But WEP is better than nothing, and you can and should enable it on all 802.11b-based wireless networks.
A newer security method, dubbed Wi-Fi Protected Access (WPA), has become available with Wireless-G products and has, in some cases, been extended to 802.11b equipment as well. Currently making the rounds with the IEEE standards body, WPA answers all of the problems with WEP and for the first time gives home networks a viable security infrastructure. WPA automatically changes its rigorously created encryption keys, on the fly and at short intervals, preventing hackers from breaking the encryption and hacking the network. Also, WPA uses an 8- to 63-character pass phrase (like a password that can also include spaces and special characters) to secure the wireless network. You must enter the same pass phrase in both the wireless AP and in the configuration dialog for the Wireless-G card of any PC connecting to the network. WPA is a simple system to set up and use, and yet it supplies excellent security defenses.
Network base stations and routers also offer other security options that you need to investigate. For example, most of these devices include hardware firewalls, which you can configure to block traffic coming in and out of your home network. Network traffic can be blocked by port, which is basically a channel through which information flows. Web traffic travels on port 80 and email travels on port 25. Router manufacturers typically enable firewalls by default. Also, Windows XP and Mac OS X machines include software firewalls that can provide inbound firewall protection at the machine level.
Armed with this basic wireless networking information, you can dive into the wireless world and experience the benefits of using your home technology anytime and anywhere. The article Quick Looks at Wireless Networking Products provides a brief overview of a few available wireless networking products.