Wireless Networking

Wireless networking has been around for some time, but many people in the early days of wireless networking abandoned it due to compatibility problems and a general lack of reliability. Wireless networking has come a long way since then, and Windows XP Professional includes a number of features that support common wireless networking standards and hardware. In short, if you need a wireless network, Windows XP has what you need to create and configure it.

Understanding Wireless Networking

Just as there are different wired networks, such as Ethernet and HomePNA, there are also several different types of wireless networks. These different types of wireless networks define different standards that hardware manufacturers must adhere to when creating wireless networking components and devices. The following bullet list gives you the skinny on each of the major types:

• Infrared  Infrared wireless uses an infrared beam to transmit data from one device to the next, and is most often used in PC devices. For example, wireless keyboards, mice, printers, and game devices can connect with an infrared port on your computer. Additionally, laptops and PDAs can connect with a desktop computer for data transfer. Infrared is a great solution for device-to-PC connectivity, but in terms of an actual LAN, infrared is not a preferred connectivity method.

• Wireless personal area networks (WPANs)  A WPAN is a personal area network, meaning it resides in one generalized space, such as a room. In other words, a personal area space is the area surrounding a person. WPANs are useful for wireless network computing in one location, or wireless networking between PDAs, cell phones, laptop computers, and so on. WPANs can make use of infrared connections for objects that are very close, or you can use Bluetooth, which communicates through radio waves up to 30 feet. The IEEE has established a working group for the development of WPANs, numbered 802.15. You can learn more about the standard by simply searching for IEEE 802.15 on any search engine.

• Wireless local area networks (WLANs)  A WLAN is a wireless network that exists within one geographical location, such as in a home, office building, school, or other such structure. The IEEE 802.11 standard for WLANs defines transfer rates at 1–2 Mbps. As you can see, the 802.11 standard was rather slow. However, today, the new IEEE standard for WLAN networking is 802.11b, which defines data transfer rates of up to 11 Mbps using a 2.4 GHz frequency band. 802.11b is the popular standard today, which gives you speeds comparable to a typical Ethernet network.

• Wireless metropolitan area networks (WMANs)  WMANs allow communication between different locations within a single metropolitan area. For example, let’s say your company resides in New York, but there are three offices in different locations in the city. Using wireless technologies, a WMAN could be created so that users between those different offices could connect.

• Wireless wide area networks (WWANs)  A WWAN connects WLANs that are separated over wide geographic areas. For example, if your company has offices in New York, Seattle, and Dallas, a WWAN could be used to wirelessly connect the different WAN network segments. WWAN technologies involve the use of satellite communications maintained by service providers, and use the same technologies used in cellular phones and wireless PDAs.

Both Windows XP Professional and Windows XP Home editions support infrared and 802.11b wireless networking. The 802.11b standard, which is also called Wi-Fi, is the most popular wireless networking standard in use today, providing transfer rates of around 11 Mbps. In a Wi-Fi network, you have a range of up to 300 feet from point to point, and it provides the best wireless security that is currently available. Since Wi-Fi is the most popular, you’ll find plenty of wireless network devices at any computer store that are compatible with Windows XP.

Note 

If you are shopping for wireless devices, look for compatibility information right on the box. You should see an “802.11b standard” or “Wi-Fi standard” note on the box as well.

Understanding Infrared

Infrared technology uses a line-of-sight infrared beam to send data from one device to the next. It is the same principle as a grocery store scanner. Since this is a line-of-sight technology, the two infrared devices must be in range and aligned (pointing to each other). The single infrared beam then transfers the data. Because you have to line up the two infrared ports on the two computers or the device (such as a PDA) and the computer, infrared networking is not as practical as Wi-Fi.

Understanding Wi-Fi

Wi-Fi networks provide two different topologies or modes. Wireless NICs can support either of the two modes, which are called infrastructure mode and ad hoc mode. In infrastructure mode, an existing wired LAN, such as Ethernet, extends to include wireless devices. The wireless devices use a hub, called an access point, that connects to the wired LAN’s hub. In other words, the access point manages all of the traffic between the wired network and the wireless devices, just as a typical hub might do. Like a hub, the access point can support a certain number of wireless clients, depending on the model you purchase. You can also use several access points in a daisy chain fashion, if necessary.

The second kind of mode is ad hoc mode. Ad hoc mode allows one wireless computer to connect to another without the use of an access point. For example, let’s say you have four wireless computers in the same room. Rather than using an access point, the computer’s wireless NICs can be configured to use ad hoc mode. The four computers can communicate with each other, and since no interface is needed with a wired network, an access point is not necessary.

The good news is you can also use infrastructure mode and ad hoc mode at the same time, through a process called zero configuration. When in infrastructure mode, all wireless NICs look for an access point. If one is not found, the NICs switch to ad hoc mode so that communication with other computers within range can occur. Windows XP can automatically configure wireless NICs from infrastructure mode to ad hoc mode, and vice versa.

Understanding Wireless Security

Unless security is your passion, most of us would rather not spend our time thinking about or worrying about security. However, in an age of electronic theft and malicious networking attacks, security is an ever-important issue, and in fact, the problems with wireless security have kept many networks from implementing wireless features.

Tech Talk: Wireless Networking Hardware

So, what do you need to configure a wireless network? As with other types of networking, you'll need wireless NICs that are compatible with Windows XP and you'll need an access point, if you intend to use infrastructure mode. Of course, no cabling is necessary, with the exception of an RJ-45 cable to connect the access point to an Ethernet hub.

Wireless NICs are readily available as PCI internal NICs, USB external NICs, and PCMCIA cards for laptop computers. Generally, if you buy an internal PCI NIC, you must also buy the wireless PCMCIA card that plugs into the PCI NIC. In other words, most wireless PCI NICs simply provide a way to use the PCMCIA wireless radio NIC on the PC. Each wireless NIC has a miniature antenna for transmitting and receiving wireless data. As you might imagine, major NIC providers such as NetGear, Linksys, SMC, and other vendors provide wireless NICs. As a general rule, wireless NICs will cost you between $60 and $100, depending on the manufacturer and the type (PCMCIA costs more). They are a little more expensive than Ethernet or HomePNA NICs, but the price difference is not enough to prohibit you from using a wireless network. Make sure that any wireless NIC you buy is compatible with 802.11b.

The access point looks somewhat like a wired hub (except there are no ports for cable connections) with a small antenna. You connect the access point to the Ethernet or HomePNA network with an RJ-11 or RJ-45 cable as needed. Wireless clients connect to the access point and then the wired network. Access points generally cost around $150–500, depending on what you want and the brand. As with hubs, there are many options to choose from, and some wireless access points also function as a router for a DSL or cable connection, in the event that you want a completely wireless network.

The good news is Windows XP supports the major wireless security features that you may need to implement. 802.11b contains a basic security feature for access points called the Service Set Identifier (SSID). An SSID is a known security identifier taken from the NIC on each computer. The access point is aware of the SSID, and once it is taken from the NIC, an association with the NIC and the SSID is made on the access point. However, the SSID is not encrypted, which makes it available for theft during transit. As you can see, the 802.11b security standard really isn’t that secure.

However, there is another security standard that is commonly supported by wireless hardware called the Wired Equivalent Privacy (WEP). This security standard provides a 60-bit encryption scheme. The encryption scheme prevents theft of data that is airborne, and this built-in standard provides a great measure of security, especially for home and small office wireless networks. Along with WEP, many wireless NICs also support a standard called 802.1x. The 802.1x standard provides authentication for access to Ethernet networks over a wireless access point. Using 802.1x, the access point authenticates users in conjunction with server software on the Windows network. Most major brands of wireless NICs support both the WEP and 802.1x standards, so make sure you read the box before purchasing any particular brand of wireless NIC. Although you may not be worried about security or need these standards, it is good to know that your NICs support them.