In this week's wireless article, I'm revisiting the 802.11b home network. There's lots of new equipment available, and I'll show you how to use it at home or in the small office environment. Even if you already have a WiFi network set up, don't miss the section titled "Some Guidelines for Wireless Networking" for my tips on how to better secure your network.

What You Need

If you're still using a dial-up modem to access the Internet, it's time to consider broadband. Depending on where you live, you can either opt for a cable or ADSL/DSL solution. A cable solution uses a cable modem such as the Motorola SB4200 SURFboard to connect to an access point, such as those used for cable TV. On the other hand, an ADSL/DSL modem uses the phone line to connect to the Internet.

The advantage of using a cable modem is that the connection is always on; there is no need to dial up to a server. The same can be true for ADSL/DSL, though it still takes a short while to reestablish a connection after it has been disconnected due to inactivity. Speed-wise, you could possibly achieve speeds from 256Kbps to 512kbps for an ADSL/DSL connection, while the cable modem can achieve a speed of 1.5Mbps. Note that speed depends on your service provider.

The Motorola SB4200 cable modem
Figure 1. The Motorola SB4200 cable modem

The cable/ADSL/DSL modem usually comes with two types of interfaces that you connect directly to your computer--USB or Ethernet. But doing so only allows one computer to connect to the Internet. Instead, by using a router, more than one computer can have access (in this case, your modem must support the Ethernet connector). Since most ISPs provide only a single IP address for a cable/ADSL/DSL connection, you need a router that is able to perform Network Address Translation (NAT). NAT translates multiple IP addresses on the local network to a single IP address that is sent out onto the Internet.

But the point of this endeavor is going wireless, so we need to find a wireless access point (AP) that comes with a router. The Linksys BEFW11S4 is a good example; it's an 802.11b wireless access point with a four-port switch. 802.11b devices can transmit data at a maximum data rate of 11Mbps, with an effective range of about 150 feet. But don't be misled by these numbers--in practice, you can expect a much lower data rate, and the effective range is dependent on the obstructions placed between your AP and your receiver.

The Linksys BEFW11S4 Wireless Access Point with 4-port switch
Figure 2. The Linksys BEFW11S4 Wireless Access Point with 4-port switch

You connect your cable/ADSL/DSL modem to the WAN port of your wireless access point (plus up to four computers with Ethernet cables to the four-port switch). I like to place my wireless access point near my desktop computer so that I can connect it directly using an Ethernet cable.

Rear of Linksys BEFW11S4
Figure 3. Rear View of the Linksys BEFW11S4

With the above setup, all of your computers, connected directly to the access point via Ethernet cables, can now surf the Internet! Check the IP address of each computer connected; they should all be different.

Now let's turn to the wireless portion of things. First, you might have a notebook computer that you want to connect to your home network. For this purpose, you can easily get a wireless PCMCIA card for your notebook, such as the Linksys WPC11.

The Linksys PCMCIA 802.11b Wireless Adapter
Figure 4. The Linksys PCMCIA 802.11b Wireless Adapter

If you want to enable wireless access for your desktop, you have two choices of adapters--PCI or USB. The Linksys WMP11 is an 802.11b PCI card that allows your desktop to connect to the network wirelessly:

The Linksys WMP11 802.11b PCI Wireless Adapter
Figure 5. The Linksys WMP11 802.11b PCI Wireless Adapter

If you do not want to open up your computer casing, or you simply want to share a wireless adapter among many computers, the Linksys WUSB11 is a good choice. Simply connect the USB wireless adapter to the USB port on your computer and you can get on the network.

The Linksys WUSB11 USB Wireless Adapter
Figure 6. The Linksys WUSB11 USB Wireless Adapter

Figure 7 shows a typical wireless network setup:

A Typical Wireless Network Setup
Figure 7. A Typical Wireless Network Setup

Configuring Wireless Devices

Once all of the necessary devices are installed, it's not difficult to test the wireless connection. Your wireless adapter comes with utilities to change its settings. In my case, I'm using the software that came with the Linksys PCMCIA card.

Examining the Link Quality and Signal Strength of the Wireless Connection
Figure 8. Examining the Link Quality and Signal Strength of the Wireless Connection

Under the Link Info tab, it shows that my link quality and signal strength are pretty good. In general, the closer the wireless adapter is to the wireless access point, with a clear line-of-sight, the better the signal quality.

Specifying the Mode and SSID for the Wireless Network
Figure 9. Specifying the Mode and SSID for the Wireless Network

Under the Configuration tab, you can select the wireless mode--Infrastructure or Ad Hoc. Infrastructure mode uses wireless access points, while Ad Hoc mode is for peer-to-peer communication. In my case, I selected Infrastructure mode.

The SSID (Service Set Identifier) acts like a "password." All wireless devices wanting to participate in a particular wireless network must specify a SSID. The wireless devices will not be able to participate in this network if the SSID is not specified (or if it is not stated correctly). In my case, the default SSID is "linksys." You are strongly advised to change this to something else. See the next section on SSID.

By default, encryption is not enabled. Encryption is important, because hackers equipped with the necessary devices can sniff the packets transmitted by the wireless network, thereby compromising your data. Wired Equivalent Privacy (WEP) is a protocol used for encrypting packets on a wireless network. It uses a 64-bit (or 256-bit, depending on the vendor) shared key algorithm. Using WEP will increase the protection on your data, but doing so will reduce the effective data rates.

Some Guidelines for Wireless Networking

Though your new wireless network allows you to have the freedom to surf the Internet anywhere in your house, it's also good news for your close neighbors, because some of them can now surf the Internet for free! Unlike a wired network, where you need to have physical access to a network point in order to gain access to the network, a wireless network extends beyond the four walls of your house.

Most wireless access points and routers provide a Web-based configuration program for configuring the wireless access point. Below are some guidelines for "securing" your wireless network:

  • Change the default SSID. Most people don't even bother to change the default SSID provided by a wireless access point. If your neighbor knows that you are using a Linksys wireless access point (say, by seeing the boxes you throw away), they could easily try the default SSID. Always change the SSID to something obscure, and never try to use your company name or your personal name. These names are too easy to guess.
  • Disable SSID broadcast. By default, most wireless access points will broadcast the SSID to all wireless devices; anyone with a wireless network card can detect the SSID you use in your network and gain access to your network.
  • Use MAC address filtering. If you have a small number of users in your wireless network (which is usually the case), you can use MAC address filtering. With MAC address filtering, you enter the MAC address of your network card and manually enter this number into your wireless access point. Only MAC addresses that have been registered with the wireless access point are able to gain access to your network. You can usually locate the MAC address of your network card on the device itself.
  • Always change the default user name and password for your wireless access point. It's too easy for people to guess the default user names and passwords used in wireless access points.
  • Turn off DHCP. Use static IP addresses if the number of users on the network is small. Turning off DHCP will prevent wireless sniffers from seeing the IP addresses being used.
  • Refrain from using the default IP subnet. Most wireless routers use the default 192.168.1.0 network. It is easy for people to guess the IP addresses used and illegally gain access to the network.
  • Use WEP for encryption of packets. If you are concerned about the confidentiality of information transmitted by your wireless network, you may wish to enable WEP encryption. Though WEP has been proven to be "crackable," it still acts as a deterrent against packet sniffing for everyone but ardent hackers.

Summary

A common concern about "going wireless" is 802.11's limited data transfer rate. While the theoretical speed of 11Mbps already seems slow compared to Ethernet's 100Mbps (and most cable/ADSL/DSL modems don't even come close to 11Mbps anyway), this isn't a problem if your primary motivation is to access the Internet. 802.11b's bandwidth is more than sufficient for Web work.

However, if you're designing a wireless network in a large work environment (where you may have a faster connection to the Internet) that requires a much higher data rate, you should also take a look at my article that looks at two faster standards that are now in place-802.11a and 802.11g. Have fun with your wireless network!


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