Wireless Network

Building a Wireless Network

If you want to take advantage of public WiFi hotspots or start a wireless network in your home, the first thing you'll need to do is make sure your computer has the right wireless gear. Most new laptops and many new desktop computers come with built-in wireless transmitters. If your laptop doesn't, you can buy a wireless adapter that plugs into the PC card slot or USB port. Desktop computers can use USB adapters, or you can buy an adapter that plugs into the PCI slot inside the computer's case. Many of these adapters can use more than one 802.11 standard.

Once you've installed your wireless adapter and the drivers that allow it to operate, your computer should be able to automatically discover existing networks. This means that when you turn your computer on in a WiFi hotspot, the computer will inform you that the network exists and ask whether you want to connect to it. If you have an older computer, you may need to use a software program to detect and connect to a wireless network.
Being able to connect to the Internet in public hotspots is extremely convenient. Wireless home networks are convenient as well. They allow you to easily connect multiple computers and to move them from place to place without disconnecting and reconnecting wires.
If you already have several computers networked in your home, you can create a wireless network with a wireless access point. If you have several computers that are not networked, or if you want to replace your Ethernet network, you'll need a wireless router. This is a single unit that contains:
1. A port to connect to your cable or DSL modem
2. A router
3. An Ethernet hub (ethernet.htm)
4. A firewall
5. A wireless access point
A wireless router allows you to use wireless signals or Ethernet cables to connect your computers to one another, to a printer and to the Internet. Most routers provide coverage for about 100 feet (30.5 meters) in all directions, although walls and doors can block the signal. If your home is very large, you can buy inexpensive range extenders or repeaters to increase your router's range.
As with wireless adapters, many routers can use more than one 802.11 standard. 802.11b routers are slightly less expensive, but they're slower than 802.11a or 802.11g routers. Most people select the 802.11g option for its speed and reliability.
Once you plug in your router, it should start working at its default settings. Most routers let you use a Web interface to change your settings. You can select:
• The name of the network, known as its service set identifier (SSID) -- The default setting is usually the manufacturer's name.
• The channel that the router uses -- Most routers use channel 6 by default. If you live in an apartment and your neighbors are also using channel 6, you may experience interference. Switching to a different channel should eliminate the problem.
• Your router's security options -- Many routers use a standard, publicly-available sign-on, so it's a good idea to set your own username and password.
Security is an important part of a home wireless network, as well as public WiFi hotspots. If you set your router to create an open hotspot, anyone who has a wireless card will be able to use your signal. Most people would rather keep strangers out of their network, though. Doing so requires you to take a few security precautions.
To keep your network private, you can use one of the following methods:
• Wired Equivalency Privacy (WEP) uses 64-bit or 128-bit encryption. 128-bit encryption is the more secure option. Anyone who wants to use a WEP-enabled network has to know the WEP key, which is usually a numerical password.
• WiFi Protected Access (WPA) is a step up from WEP and is now part of the 802.11i wireless network security protocol. It uses temporal key integrity protocol encryption. As with WEP, WPA security involves signing on with a password. Most public hotspots are either open or use WPA or 128-bit WEP technology.
• Media Access Control (MAC) address filtering is a little different from WEP or WPA. It doesn't use a password to authenticate users - it uses a computer's physical hardware. Each computer has its own unique MAC address. MAC address filtering allows only machines with specific MAC addresses to access the network. You must specify which addresses are allowed when you set up your router. This method is very secure, but if you buy a new computer or if visitors to your home want to use your network, you'll need to add the new machines' MAC addresses to the list of approved addresses.
Wireless networks are easy and inexpensive to set up, and most routers' Web interfaces are virtually self-explanatory.

Which one is right for you?
Home and business networkers looking to buy wireless local area network (WLAN) gear face some difficult choices. Vendors sell many products that conform to different wireless standards such as 802.11a, 802.11b, 802.11g, and Bluetooth. To make an educated network building decision, one must understand the relative pros and cons of each of these technologies.
802.11
In 1997, the Institute of Electrical and Electronics Engineers (IEEE) created the first WLAN standard. They called it 802.11 after the name of the group formed to oversee its development. Unfortunately, 802.11 only supported a maximum bandwidth of 2 Mbps - too slow for most applications.

For this reason, ordinary 802.11 wireless products are no longer being manufactured.
802.11b
IEEE expanded on the original 802.11 standard in July 1999, creating the 802.11b specification. 802.11b supports bandwidth up to 11 Mbps, comparable to traditional Ethernet.
802.11b uses the same radio signaling frequency - 2.4 GHz - as the original 802.11 standard. Being an unregulated frequency, 802.11b gear can incur interference from microwave ovens, cordless phones, and other appliances using the same 2.4 GHz range. However, by installing 802.11b gear a reasonable distance from other appliances, interference can easily be avoided. Vendors often prefer using unregulated frequencies to lower their production costs.
• Pros of 802.11b - lowest cost; signal range is best and is not easily obstructed
• Cons of 802.11b - slowest maximum speed; supports fewer simultaneous users; appliances may interfere on the unregulated frequency band
802.11a
When 802.11b was developed, IEEE created a second extension to the original 802.11 standard called 802.11a. Because 802.11b gained in popularity much faster than did 802.11a, some folks believe that 802.11a was created after 802.11b. In fact, 802.11a was created at the same time. Due to its higher cost, 802.11a is usually found on business networks whereas 802.11b better serves the home market.
802.11a supports bandwidth up to 54 Mbps and signals in a regulated frequency spectrum around 5 GHz. This higher frequency compared to 802.11b limits the range of 802.11a networks. The higher frequency also means 802.11a signals have more difficulty penetrating walls and other obstructions. Because 802.11a and 802.11b utilize different frequencies, the two technologies are incompatible with each other. Some vendors offer hybrid 802.11a/b network gear, but these products simply implement the two standards side by side (each connected devices must use one or the other).
• Pros of 802.11a - fastest maximum speed; supports more simulatenous users; regulated frequencies prevent signal interference from other devices
• Cons of 802.11a - highest cost; shorter range signal that is more easily obstructed
802.11g
In 2002 and 2003, WLAN products supporting a newer standard called 802.11g began to appear on the scene. 802.11g attempts to combine the best of both 802.11a and 802.11b. 802.11g supports bandwidth up to 54 Mbps, and it uses the 2.4 Ghz frequency for greater range. 802.11g is backwards compatible with 802.11b, meaning that 802.11g access points will work with 802.11b wireless network adapters and vice versa.
• Pros of 802.11g - fastest maximum speed; supports more simulatenous users; signal range is best and is not easily obstructed
• Cons of 802.11g - costs more than 802.11b; appliances may interfere on the unregulated signal frequency
What About Bluetooth?
Bluetooth is an alternative wireless network technology that followed a different development path than the 802.11 family. Bluetooth supports a very short range (approximately 10 meters) and relatively low bandwidth (1 Mbps). In practice, Bluetooth networks PDAs or cell phones with PCs but does not offer much value for general-purpose WLAN networking. The very low manufacturing cost of Bluetooth appeals to vendors.
Summary
Each wireless network technology available today offers some advantage over the others. For those looking to build a new WLAN, 802.11g is the most promising option to consider.