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Wireless Networking : What, Why and How

by ONE/Northwest
April 17, 2003

Wireless networks can connect your computers without the hassles of running Ethernet cables around your office. Read on to find out whether wireless is right for you, and what you need to get started

Why Wireless?

A wireless network is perfect for places where it is impractical or inconvenient to connect computers with traditional Ethernet wiring. If you are already tripping over wires in your office or do not want to put additional holes in your walls, wireless is the way to go. It is also a great way to get a network connection to an infrequently used location like a conference room. A wireless network is a little bit more expensive (about $60 more per computer), but it’s not an all or nothing proposition – your network can have both wired and wireless connections.

Why buy “Wi-Fi?”

A few years ago, a bunch of geeky people sat down and created technical standards for how wireless computer networking products should work. By creating standards, different companies can create products that all work together even if they are from different manufacturers. As computer geeks, they used geeky terms to refer to these standards such as “IEEE 802.11a” and IEEE 802.11b”. The most common wireless networking products today use the “802.11b” standard. In an attempt to make this more intelligible for humans, the marketing people started to refer to 802.11b as “Wi-Fi”, short for “wireless fidelity.”

In addition, 802.11a wireless products have recently hit the market. 802.11a wireless products are more expensive than 802.11b "Wi-Fi" products, but they offer faster transmission rates and are less prone to interference from microwave ovens and certain cordless phones. However, most small office networks don't need the added speed -- or expense -- of 802.11a wireless right now. In addition, 802.11a radio signals don't cover as much ground as 802.11b signals -- depending on your office environment, this may be a positive or a negative.

Let’s talk speed

Wi-Fi networking products transmit data at the 2.4 GHz frequency, much like newer cordless phones. When there is a strong signal, data moves between computers at 11Mbps (megabytes per second). Older wired Ethernet networks transmit data at speeds up to 10Mbps while newer ones can go up to 100Mbs per second. However, these numbers are only relevant when thinking about how fast information travels between two computers within your office. Your connection to the Internet will most likely be your biggest bottleneck and 11Mbps is about 20-40 times faster than most high speed Internet connections.

When the signal gets weaker (as you move the computers farther apart or have more walls in between), the transmission speed gradually slows down to 1 to Mbps, which is still pretty fast. The signal can travel up to 1000 ft, so you should have no trouble in your small office. The biggest problem is that the signal may travel too far (see security below).

802.11a products transmit data at speeds up to 72Mbps at the 5 GHz frequency. But as we noted above, these products are about twice as expensive as Wi-Fi products, and have a slightly shorter operating range.

What do you need and what will it cost?

The center of your wireless networking universe is the “wireless router.” This is the device that connects directly to the Internet and links all of your computers together. Many routers have built-in hubs (so that you can connect wired computers to your network) and print servers (so you can share a printer on your network). They also have built-in firewalls to protect your network from hackers on the Internet. SMC Networks makes a well-regarded router (SMC Barricade 7004AWBR) which costs about $150.

For every wireless computer on your network, you will need a wireless networking card. These are about $50-$75 each and are available for both laptops (which use USB or PCMCIA cards) and desktops (USB or PCI cards). In contrast, a wired computer needs an Ethernet adapter (which may be built in to your computer already, or can be purchased for $15) and a cable (about 20 cents per foot).

It is significantly easier to get a wireless network working if the wireless computers are running Windows XP, which has built-in support for wireless networks. But virtually any machine can be connected to a wireless network without too much difficulty.

Wireless Access Point vs Wireless Router?

A wirelss access point adds wireless capability to an existing network. It does not share your Internet connection between multiple computers. A wireless router will share your internet connection, add wireless, and act as a firewall. Most people simply purchase a wirless router. On the other hand, if you already are sharing your Internet connection with a wired Internet router such as the Linksys BEFSR41/BEFSR11 or NetGear RT311/314, then you may want to just add a wireless access point.

Be Secure!

The range of a wireless network can be a wonderful thing. You can surf the internet while sitting in a chair outside or receive email while in a meeting. However, it also means that people in the office next door or someone parked in a car outside your building could conceivably access your network and use your internet connection. Fortunately, there are easy steps you can take to make it more difficult unauthorized computers from connecting to your WAN:

1) WEP

One way to protect your network is to use Wired Equivalent Privacy (WEP). This security protocol is included in all Wi-Fi certified products and can protect your data by encrypting it while it is being transferred from one computer to another. A long sequence of letters and/or numbers (the “key”) is entered for both the wireless router and the wireless computer. Unless a computer knows the key, it can neither connect to the router nor intercept the data being transmitted.

That’s how it goes in theory. However, the protocol is not as secure as once believed. WEP is also implemented inconsistently across platforms, products, and drivers so it can be confusing and difficult to set up. WEP can be a good way to augment the security of your wireless network, but don't rely on WEP alone. The best way to be secure is with MAC control.

2) MAC

Every network card has a unique digital "serial number." Windows refers to this as the "Physical Address" for your network connection and it is also refered to as the MAC (Media Access Control) address. The most secure way to configure your network is to specify which MAC addresses can connect to the network. You set this up in the configuration settings of your wireless router. Any computer without one of these specified "serial numbers" will not be able to connect to your network.

Between them, these two steps will provide reasonably good -- but not 100% ironclad -- security for your wireless network. None of the current security mechanisms for wireless networks are 100% ironclad secure. Simple measures will make your network difficult -- but not impossible -- to break into, and should deter casual intruders. However, a highly skilled and motivated hacker who can get near your office and listen in on several hours worth of your wireless broadcasts could conceivably mount a cryptographic attack that would give them access to your network.

If you have extremely sensitive data on your network, and/or are concerned that there are people who are highly motivated to break in, you may want to think twice before deploying a wireless network. For more detailed information on securing wireless networks, see the resources listed below.


More Information

Wireless product shopping

Wireless security tips
Exploiting and Securing Wireless Networks

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