What is Wi-Fi and 802.11b, 802.11a, 802.11g and Bluetooth?

Existing Network setups

Adding wireless capability to a network

Connecting to ADSL broadband with wireless

Combined wireless and ADSL routers

Adding wireless to an existing BT Business broadband network

Netgear Home Networking Solutions Guide (1.7MB PDF)

Wireless Networking, sometimes known as Wi-Fi, or by the transmission protocol used of 802.11b, 802.11a or 802.11g, allows you to connect computers on a network or to the internet without cables. How? Wireless Networking is a wireless technology like a cell phone. Wireless enabled computers send and receive data indoors and out; anywhere within the range of an wireless access point. And the best thing of all, it's fast. In fact, it's several times faster than the fastest cable modem connection. A Wi-Fi CERTIFIED PC Card or similar device means that you will be able to connect anywhere there are other Wi-Fi CERTIFIED products — whether you are at home, the office or corporate campus, or in airports, hotels, coffee shops and other public areas equipped with a Wi-Fi access available.

There are four wireless-networking standards available depending upon your requirements.

1. Wi-Fi (802.11b), or Wireless Fidelity which is also known as 802.11b is the corporate choice and has a suitably wide range for use in big office spaces. Wi-Fi (802.11b) is currently the most popular and least expensive wireless LAN specification. It operates in the 2.4GHz radio spectrum and can transmit data at speeds up to 11Mbps within a 30m range. It can affected by interference from mobile phones and Bluetooth devices which can reduce the transmission speeds. It is the standard fitment to many wireless laptops including the new Centrino based models.

2. 802.11a, has a couple of advantages over Wi-Fi. It runs at a less-populated frequency (5.15GHz to 5.35GHz) and is therefore less prone to interference. Its bandwidth is much higher, at a theoretical peak of 54Mbps. Even though actual throughput is closer to 22Mbps. Some manufacturers offer proprietary modes that can push throughput a little higher. Its main problem is its shorter range: 15m compared to Wi-Fi's 30m, forcing you to buy more access points to ensure full coverage, it is also more expensive not compatible with Wi-Fi (802.11b). There are dual band cards and access points available from some manufactures that automatically switch between the two to maintain a connection.

3. 802.11g is the latest standard and promises to be the most popular format in the furture. It combines the speed the 802.11a with the backward compatibility of 802.11b. It has the same longer range of 802.11b but in the same way it can be affected by interference.

4. Bluetooth is a somewhat different standard from Wi-Fi or 802.11a, offering much more flexibility but on a smaller, 'personal area network' scale and primarily is being seen as a replacement for I.R (Infa Red) and wireless connection to Bluetooth enabled electronic devices. Its actual throughput is only 300Kbps, and its range around 10m. But unlike Wi-Fi and 802.11a/g, which require adapters, routers, gateways, access points and synchronised setup schemes to connect devices, any devices with a Bluetooth radio and antennae or Bluetooth enabled can speak to each other with little or no preparation.

Wireless networking basics

When upgrading to wireless a network the overall layout can be a bit confusing. If you are not overly familiar to network topology, here we will hopefully be able to make a bit easier to understand what you need to add to your existing network setup to give you a wireless network capability.

In Figure.1 we can see a typical network setup as used by many small home/offices today. This normally consists of a dedicated server connected to a group of PC's or Macs via a network switch or hub. If you have the simpler Peer to Peer network then you would just have the computers without the server as in Figure.2

Figure.1

Figure.2

To give your existing network a wireless capability, all you need to do is add a wireless access point to your network switch/hub and wireless PCMCIA cards in your laptops or PCI cards in your PC/Mac desktop computers as shown in Figure.3. Once this is done the computers that use the wireless cards are now connected to the switch/hub in the same way as if they used a normal network cable. One of the major benefits of this is that you don't have all the hassle of laying new cables in to an existing office setup and depending upon the wireless access point used you can have up to 32 or more wireless computer users per access point, without having to buy a bigger switch/hub with more ports.

Figure.3

With the advent of widespread broadband access to the Internet, many offices could use this opportunity not only to upgrade to a permanent Internet connection but also to go wireless at the same time. In Figure .4 the existing network has been connected to the Internet via a ADSL modem router together the wireless access point. Now every computer on the network whether it is wired or wireless would have a potential permanent Internet connection. If you have a cable Internet provider like NTL or Telewest then you would use a cable ADSL router without a built in modem.

Figure.4

Carrying on with the previous theme, we could reduce the number of boxes required by using a combined wireless access point and ADSL modem router as can be seen in figure.5. This provides all the same functionality as in Fig.4 but with fewer boxes.

Figure.5

Many of the business that have gone with the BT business broadband setup will use the four port router that came as part of the package, this allows you to connect up to 4 computers to the Internet. In Figure.6 you can see that by adding a wireless access point to one of the ports of the router you can now give wireless Internet access for up to 32 or more users per access point. This would be ideal for anyone with an existing BT broadband setup that did not want to change the router but wanted to add wireless and or more users that could access the Internet.

Figure.6