Auldfart's How To Guides   How wireless networks work Networks, the once proud preserve of the computing elite, can now be found everywhere.  Large businesses, small offices and homes now all boast a computer network of some description or other, and this isn’t including the various ‘invisible’ networks that link everything from our cash points to the mobile phone infrastructures. With the continuing rollout of ADSL, networks are becoming more and more important as time goes by.            There is a downside to the traditional computer network though, and that’s cabling: unsightly, potentially dangerous and difficult to route around your home.           Far too long for most small buildings and too short for long distance connections, cables are the bane of anyone that has ever been responsible for networking a home.            Factor in the need to anchor your laptop to one of these wires if you want to access the Internet, and you have a less-than-appealing situation on your hands. As you have probably guessed from the title, the rather neat solution to the ‘snake’s nest’ problem is a wireless network. This uses radio frequencies to send information between your machines instead of using wires.             Not only does this mean that you don’t need to drill holes in your walls to lay cables, but you can also use your laptop while roaming around your house. The question is how does wireless networking actually work? Protocol harem              There are two wireless network standards used for computer networks, namely HomeRF and Wi-Fi. Both of these standards are based on the original wireless Ethernet specification, as defined by the Institute of Electrical and Electronics Engineers, namely IEEE 802.11.            This standard defines two-way communication between devices using spread-spectrum radio waves in the 2.4GHz range, with a maximum speed of 2Mbps.            The 802.11 standard defines support for Direct-Sequence Spread Spectrum (DSSS) and Frequency-Hoping Spread Spectrum (FHSS) communications.               DSSS communication system splits each byte of data into several parts and sends these parts concurrently (making use of a lot of the available bandwidth).              The Wireless Ethernet Compatibility Alliance (WECA) based the Wi-Fi standard on DSSS communications, offering support for communications at speeds up to 11Mbps. This standard is also known as 802.11b.           FHSS communication sends a short bursts of data, changes frequencies and then sends another burst. The positive side of FHSS is that it enables several independent networks to operate without fear of interference.  It’s noticeably slower than DSSS communication, but the hardware behind this technology is affordable. FHSS forms the basis of the SWAP communications standard as used by HomeRF hardware and supports communication at up to 1.6Mbps.           The big difference between HomeRF and 802.11b is that the former is relatively cheap and easy to set up, while the latter has been designed with businesses in mind, and is therefore faster and more reliable.              While you may not necessarily need to communicate at 11Mbps, the fact that you can integrate 802.11b hardware with your existing hardware network makes it a more attractive option and this has quickly become the standard of choice for most networks. Unwanted interference There are two problems associated with wireless networking: security and interference.              These problems stem from the fact that wireless networks broadcast using radio waves, and these waves can be intercepted by other devices, while other equipment operating on the same frequency will cause interference. If you’re sending and receiving sensitive information then there is a solution to the security issue in the form of encryption.           Most hardware supports 40- and 108-bit WEP (Wired Equivalency Protocol) data encryption, which can help to keep your data private, but several recent tests have shown WEP to be inadequate. SSID and MAC can help build a more secure network, and this is one area that should see more development soon.            The other factor is interference from other devices, and for Wi-Fi this can be quite a problem, especially if you have an old microwave oven or DECT (cordless) phone within range of the network. Even the new Bluetooth can make use of the 2.4GHz frequency band and could hop on to this frequency.            The good news is that the Wi-Fi will renegotiate the transfer speed if it’s unable to communicate reliably, slowing down to 5.5, 2 or 1Mbps to maintain a consistent connection.              Devices based on the SWAP standard aren’t as affected by interference from other devices, but they’re not without problems. For such devices, walls and solid objects can affect the quality of the signal, which will reduce performance even further.  Where possible you want to use such devices out in the garden on a sunny day for best effect. Alan Dexter Which system? While wired networks come in various configurations, there are only two systems used for wireless networking: Client/Server and Ad-Hoc. Client/Server set up             The first system uses a central Access Point (AP), generally connected to a base station, through which all communications are transmitted. Such APs usually boast a large antenna that helps to extend the range of communication.            If the Access Point offers NAT routing and an integrated DHCP server then it is generally termed a Gateway, as it enables your devices to access the Internet. If you’re adding a wireless network to an existing Ethernet network then you shouldn’t need a Gateway, as an AP should be sufficient. Ad-Hoc set up          The Ad-Hoc system, also known as Peer-to-Peer, doesn’t have such a structured approach. Instead, each machine on the network communicates with every other machine directly.            To set up an Ad-Hoc network you don’t need an Access Point, which makes such networks cheaper to construct, but the range is often not as much as that offered by an Access Point. As usual, you get what you pay for.