Networks: Wired Ethernet and Wireless Networking - Page 2

This long page of this website deals with the equipment and software of wireless networks, access points, routers, etc., covering the 802.11b, 802.11g and 802.11n wireless networking standards, channels, network tools/utilities, WEP/WPA/WPA2 security encryption, how to install and make a network secure, wireless hotspots, high-gain antennas and range extenders - and Bluetooth. The wireless router is now the most commonly-used piece of networking equipment, having displaced wireless access points. Routers are dealt with in more detail on Page 3 of this article. Networking and Internet Problems are dealt with in a separate section of this website, consisting of three long pages of solved problems.

Note that there is a new Wi-Fi standard - 802.11ac - which uses the 5GHz band for a theoretical data throughput of 1 gigabit per second (128MB per second) that has not been ratified yet but 802.11ac routers and wireless adapters are already available (e.g., the Buffalo WZR-D1800H 802.11ac router and Buffalo wireless adapters). The latest Wi-Fi standard is expected to be finalised in late 2012 with final Working Group approval in late 2013. 802.11ac is expected to be the dominant wireless standard by 2015.

The Netgear R6300 802.11ac Dual band Gigabit Router was given its Ultimate award by exertreviews.co.uk (August 2012).

Gigabit Wireless? Five 802.11ac Routers, Benchmarked [January 2013] -

http://www.tomshardware.co.uk/wi-fi-802.11ac-router,review-32609.html

Wireless networks and networking

It would be a good idea to scroll down the page quickly just to get an idea of what is covered. Then you can start off at this point with some idea of where this article is going to be taking you...

Wireless networks that can share a broadband Internet connection are so cheap and easy to set up that they are probably now more in use by home users than wired networks.

There are two main ways of setting up a wireless network - on an Ad Hoc (peer-to-peer) basis that just involves installing a wireless adapter in each computer, or by using a wireless Access Point or base station, which is a wireless hub or switch.

It is worth clarifying the definition of Ad Hoc, since there is some confusion in wireless networking literature about this term. In particular, the IEEE 802.11 specification uses the term Ad Hoc to describe "a network composed solely of stations within mutual communication range of each other." In many other contexts, the term Ad Hoc refers to multi-hop self-configuring wireless networks.

A number of different protocols for routing in Ad Hoc networks have been proposed and evaluated. Although a great deal of research has been done on Ad Hoc routing protocols, not much real-world evaluation has been carried out.

Currently wireless networking equipment supports three standards - the earlier 802.11b standard and the current 802.11g and 802.11n standards. The new 802.11n wireless standard has at long last been ratified.

New 802.11b equipment is becoming difficult to find. Both of these standards (802.11b and 802.11g) use the 2.4GHz radio band, as does most 802.11n wireless equipment, some of which can switch between using the 2.4GHz and the 5.0GHz radio bands. In any case, 802.11n wireless equipment (routers, PCI/PCI Express adapter cards, wireless USB dongles, etc.) is the best choice for range and immunity from interference.

Other 802.11b/g/n wireless networks, baby monitors, microwave ovens, wireless Bluetooth headsets, DECT cordless phones and other wireless devices all use the 2.4GHz section of the radio spectrum, which makes it prone to interference. A dual-band 802.11n router can operate on the 2.4GHz and 5.0GHz radio bands. The 5.0GHz band is far less congested than the 2.4GHz band and its 19 channels, not all of which are available on all 802.11n routers, do not overlap, as do most of the 13 channels of the 2.4GHz radio band, of which only channels 1, 6 and 11 do not overlap. However, note that not all 802.11n wireless equipment supports the 5.0GHz frequency, which provides less range than the 2.4GHz frequency. (The higher the frequency, the less the range.)

An 802.11n router should support a feature called Wide Channel for the radio bands that it uses, which makes use of an additional wireless channel, using a process called channel-bonding, to double throughput. You can cause interference problems by enabling it for the 2.4GHz overlapping radio band, but it your router supports the 5.0GHz band, it will probably be worthwhile enabling it due to the fact that there is no channel-overlapping on that frequency.

802.11b equipment operates at a maximum theoretical data-transfer speed of 11 Mbits per second (11Mbit/s), and the 802.11g equipment operates at a maximum theoretical data-transfer speed of 54 Mbits per second (54Mbit/s). 802.11g equipment supports the 802.11b standard, but the earlier 802.11b equipment does not support 802.11g equipment. To improve the performance of the 802.11b, some manufacturers introduced an enhanced version called 802.11b+, which can achieve a theoretical maximum datastream of 22Mbits/s.

There is also another much less popular standard - 802.11a. It operates in the frequency range close to 5.0GHz, and it is banned in France and elsewhere in Europe, because that band is used for reserved communications. The bandwidth is higher, with a maximum theoretical datastream of 54Mbits/s, but the range is much smaller.

The disadvantage of using this band is brought about by its reduced wavelength, which is less than half that of the 2.4GHz band used by 802.11b equipment. This means that walls and other obstacles are much more of a problem for 802.11a devices, because they appear twice a thick to the shorter waves of the 5.0GHz frequency. (The higher the frequency, the shorter the wavelength.) Therefore 5.0GHz equipment will be far more adversely affected by obstacles and distance than equipment that uses the 2.4GHz band. This is the main reason for thinking that equipment using the 2.4GHz band will remain the more popular of the two types of equipment, even though the 5.0GHz band is much more free of radio and electrical interference and has many more channels than the 2.4GHz band.

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The 802.11n wireless networking standard has at last been ratified

September 14, 2009. - Seven years after it was proposed, the 802.11n wireless networking standard has been ratified. The ratification by the IEEE standards body means that wireless equipment manufacturers do not have to describe their products as Draft-N. The owners of existing Draft-N products should not have to worry about compatibility, because the manufacturers have guessed what the final standard would be and have tailored their products to fit it, making products that comply with Draft 2.0 of the 802.11n wireless standard. Therefore, if a wireless N product has been purchased within the last three years, such as a router, it probably already complies with the 802.11n standard. However, you should make sure that your Draft-N router is up to date, by visiting its manufacturer's support site to find out if there is new firmware available to download.

IEEE Ratifies 802.11n, Wireless LAN Specification to Provide Significantly Improved Data Throughput and Range - http://www.ieee.org/about/news/2009/...

Draft-N and 802.11n equipment compliant with the ratified 802.11 standard is backward-compatible with 802.11g equipment. For example, Draft N routers are backward-compatible with 802.11g wireless adapters commonly found in most current laptop/notebook and desktop PCs. Draft-N (and 802.11n) routers are usually faster than 802.11g routers when connected to 802.11g adapters. Moreover, they also usually have significantly long range when connected to 802.11g equipment.

The WiFi Alliance is a good website to visit for information on ratified WiFi products and standards.

WiFi Alliance - http://www.wi-fi.org/

802.11n Wireless: Is Now The Time To Deploy? -

http://www.informationweek.com/hardware/showArticle...

You can read about all of the latest information on all of the 802.11 wireless networking standards on this page:

IEEE 802.11 - http://en.wikipedia.org/wiki/802.11

Page 3 of this article provides more information on 802.11n.

Which Networking Technology Is Right For Your Home? -

"Powerline, MoCA, 802.11 wireless, or conventional Ethernet--which networking technology is right for your home? Netgear sent us product based on all four technologies and we ran them through their paces to help you decide which works best in your home."

http://www.tomshardware.co.uk/powerline-wireless-networking,review-31739.html

Wireless range extenders and other methods of extending range

Amazon.com and Amazon.co.uk sell range extenders and the purchaser reviews usually provide good advice on how to set them up if connecting them proves to be problematic. The TP-Link TL-WN822N 300MBPS High Gain Wireless N USB Adapter is a cheap USB range extender that is connected to the computer that you want to connect to the wireless network.

One purchaser commented that you have to allow a 64-bit version of Windows 7 (no doubt also a 64-bit version of Windows Vista) to obtain the driver for the device from microsoft.com instead of installing it from the driver CD, because only the 32-bit driver is provided.

Wireless G Range Extenders -

"Expand the range of your wireless network! Wireless Range Extenders offer an easy way to increase the effective coverage of your wireless network. Unlike adding a traditional access point to your network to expand wireless coverage, wireless range extenders do not need to be connected to the network by a data cable. Just put the wireless range extender within range of your main access point or wireless router, and it "bounces" the signals out to remote wireless devices." -

http://www.broadbandbuyer.co.uk/Shop/ShopSearch.asp?CategoryID=657

How to Increase Your Wi-Fi Signal [Using a mobile phone and an Ethernet cable] -

http://www.youtube.com/watch?v=LY8Wi7XRXCA&feature=related

How to get Free WiFi access anywhere, anytime [Using free software called Easy WiFi Radar] - http://www.youtube.com/watch?v=3lNqqryPBNU&feature=related

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The 802.11a standard was introduced in 1999 as a fast connection that uses the much less used 5.0GHz radio band instead of the congested 2.4GHz band used by 812.11b and the 802.11g. At one time, UK users were required to apply for a licence to use the reserved band, but that is no longer the case.

Note that 802.11g standard supports the original 11Mbit/s transfer rate of 802.11b, but might not support the 22Mbit/s or the 44Mbit/s enhancements of 802.11b+. Dataflow is 54Mbits/s maximum, the same as 802.1a (even though, in ideal conditions, only about half of this dataflow is ever achieved in practice), and the range over which the equipment can function is slightly less than the range achievable using 802.11b.

Of all the home networking systems, wireless networks are the most convenient. Special setup software is provided to configure it. After you have the base-station or wireless router in place, all you need is a wireless PCMCIA card for a notebook, or a PCI or a USB wireless adapter for a desktop PC.

Note that if you're thinking about installing an 802.11 wireless network, you should ensure that all of the components are manufactured by the same company. It is possible to mix and match components, but the setup might not run at all, or might not run as smoothly as it would if all of the components were made by the same manufacturer.

Wireless networks are still considerably slower than wired networks. The testing of wireless networks detailed in the Computer Shopper (issue 180) achieved a maximum speed of just under 1.5 megabytes (MB/s) per second (not megabits (MBit/s) per second) for a wireless network, compared to 10 megabytes per second for a wired network. I'm using megabytes per second here to give a better idea of the data transfer speed, but this is usually shown as megabits per second. [There are 8 bits of information in a byte, a kilobyte is 1024 bytes, and a megabyte is 1024 X 1024 = 1,048,576 bytes.]

Here are the theoretical maximum speeds (rarely achieved in practice) of the main current wireless network standards -

802.11b - 11Mbit/s

802.11b+ - 22Mbit/s and 44Mbit/s (802.11b with enhanced extensions)

802.11a - 54Mbit/s

802.11g - 54Mbit/s

802.11g+ - 100Mbit/s / 108Mbit/s (802.11g with enhanced extensions)

Send-and-receive tests between a PC and a laptop computer with Linksys, Netgear, 3Com, and Belkin 802.11g 54Mbit/s PCI/PC Cards installed alternatively on both of them over a 5 metre line-of-sight connection and a 15 metre hop between floors, showed that the 54Mbit/s maximum connection speed is the fruit of someone's over fertile imagination. The 5-metre send speeds fell between only 15 and 16Mbit/s, and the 5-metre receive speeds fell between 17 and 18 Mbit/s. The 15-metre send speeds fell between only 9 and 10Mbit/s, and the 15- metre receive speeds fell between only 10.50 and 11.50Mbit/s.

At present, the enhanced 802.11g+ standard is not universal but can only be used with particular brand-name proprietary equipment, so it's advisable not to employ it unless you only want to make use of the standard with the equipment that supports it. Using equipment from the same manufacturer always increases reliability, but even using a mixture of g+ and g equipment made by the same manufacturer will make the whole network work at the same level as g equipment. Such a mixture of g+ and g devices might work at the g data transfer rates if they're made by a mixture of manufacturer's, but it's not an advisable setup.

Entering 802.11g+ (or any of the other 802.11 standards) a search engine will provide links to articles on it.

Note that it is now possible to buy wireless Access Points (wireless base stations that act as a hub or switch) that support more than one of these standards. But why these particular dataflow rates are used beats me, because, even under ideal conditions, with the computers easily within the optimal range of one another, only about half or less of these rates are ever achievable in practice. Moreover, the dataflow rates decrease and fall off sharply the more unideal the conditions are or become.

Equipment that uses the 802.11g technology is now readily available. Its (rarely achieved) maximum data transfer speed (54Mbit/s) is five times that of the 802.11b technology (11Mbit/s), and it maintains backward compatibility with it.

Note that the 802.11a technology is only compatible with equipment using the same standard. It is not compatible or backward compatible with the other standards listed above.

Wireless network security: WEP, WPA and WPA2 encryption

Wireless routers that support wired connections (usually providing 4 Ethernet ports) are the main piece of networking equipment around which a home network is created. Routers are dealt with in detail on Page 3 of this article. Router manufacturers continue providing support for the older security encryption standards in order to make it possible to continue using the older equipment that supports them. WPA2-AES is the latest standard (in April 2012), which is the best to use, but not all networking hardware supports it, so WPA2-TKIP may have to be used instead. If your equipment only supports WEP, you should update it, because it is easily cracked, but the original WPA can still be used.

Visit the Q&A article on this site called How can a wireless network be made secure? to find out about data encryption and other methods of keeping a wireless network secure. Use your browser's Back button to return to this point on this page.

The following article deals with the crackability of a WPA/WPA2-encrypted WiFi network. -

http://www.tomshardware.co.uk/wireless-security-hack,review-32252.html

The following article provides the state of play with regard to the crackability of the three main wireless encryption standards used to secure wireless networks.

How To Crack WEP and WPA Wireless Networks -

Cracking WEP, WPA-PSK and WPA2-PSK wireless security using aircrack-ng -

http://www.speedguide.net/articles/how-to-crack-wep-and-wpa-wireless-networks-2724

How to install a wireless network

The wireless equipment that you use (router, switch, Wireless Access Point, etc.) will come with a user manual that provides installation instructions. Installation is getting easier to do all the time.

It's possible to have a frustrating time trying to get all the available security options working on a wireless network, but most people find that with Windows XP SP2, making the the whole thing work with 128-bit encryption, a unique SSID, and MAC-address filtering is amazingly simple. It's not uncommon to have everything working the first time on every machine, which, until I tried installing a wireless network on Windows XP SP2 computers, was something I had never experienced.

If the user manuals aren't sufficient, there is plenty of installation help available on the web. Practically Networked has plenty of useful how-to articles and troubleshooting Q&As.

For all versions of Windows, go here for some good tutorials:

http://www.windowsnetworking.com/articles-tutorials/wireless-networking/

Go to the bottom of this page for more links to useful information.

Network installation tips

As you add each new computer to your wireless network, temporarily turn off that PC's software firewall (Norton Personal Firewall, Sygate, Outpost, ZoneAlarm, etc.) until the wireless connection is made. Then re-enable the firewall, which should recognise the new connection and offer or allow you to enable automatic recognition.

Read How can a wireless network be made secure? and Why can't my wireless network work all over my house? which addresses those two most commonly asked questions of the Networking Problems pages of this site.

Using Microsoft's Flash Drive Manager to set up a wireless network

Microsoft provides a free program called FlashDrive Manager that makes working with several flash drives easy. You can even use it to set up a wireless network quickly and easily.

Each computer that you want to connect to a wirless network has to be configured manually with the required settings, but you can simplify the process by using the Flash Drive Manager to copy the settings from one computer to another.

Microsoft USB Flash Drive Manager is only available for Windows XP.

Microsoft USB Flash Drive Manager (Standard) -

http://www.microsoft.com/en-us/download/details.aspx?id=20034

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Common networking problems and How-to articles covered by the MS Knowledge Base

View the section called Networking How-to articles and problems in the Microsoft Knowledge Base on the first Networking Problems page on this site.

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How to make a wireless network secure

The most common data encryption used to protect wireless networks is called WEP, which stands for Wired Equivalent Privacy. The level of encryption varies from very weak 64-bit to much more secure 256-bit encryption.

Read the Q&A on this site called How can a wireless network be made secure? on the Network & Internet Problems pages on this website.

"Actually, there's a lot you can do to secure your wireless LAN. Most of these tips apply to 802.11b based LANs, since they're the most prevalent. But some tips are just good network security practice and can help no matter how you build your LAN..." -

http://www.practicallynetworked.com/support/wireless_secure.htm

AirSnare - from http://home.comcast.net/~jay.deboer/airsnare/ - is a free (donations welcome) tool that works on wired and wireless networks monitoring MAC addresses - unique addresses assigned to every network device on a Local Area Network (LAN) that are accessed when a new network device tries to log on to a network. The tool provides notification when it detects a new MAC address tapping into the LAN it is installed on. It can even inform on what the users are doing via the LAN and allows them to be notified that their activities are under observation.

Top 3 free Wi-Fi network security tools -

http://www.newsfactor.com/perl/story/22124.html

Comment

"Wireless devices have really dropped in price and are such a great idea for networks - especially laptop users. Many laptops are now even shipping with integrated mini-PCI wireless cards. I set up my own Wi-Fi network with an SMC router and a U.S. Robotics 22 Mbps PC Card - now I can get DSL Internet access all over my apartment. Also, my campus has Wi- Fi, so I have the same access there. There are some potential problems with wireless networking, however. I soon noticed that anyone with an 802.11b device nearby can log on to my network and have access to the Internet (I don't mind sharing that) and any shared drives (not good). So, I enabled the data encryption (WEP) so that only those with the key can actually transmit data across my Wi-Fi network. I walked around my apartment complex with my laptop in hand and noticed quite a few people are using wireless networking - without encryption. So as soon as I walked by, I was assigned an IP address on the person's LAN. That seems pretty dangerous to me!" - Jason Byers.

If you can't find any information that you need, try using a search engine to search for any of the above manufacturers, terms, or standards. You should be able to find any additional information you may require about these alternative forms of network, and tutorials on how to set them up, install drivers, and install and configure the networking software.

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Wireless hotspots

Wireless hotspots are places where you can connect a notebook computer to the Internet via a 802.11b PCMCIA network adapter, or via a laptop's inbuilt adapter. There's no need to use a high-speed network adapter at a hotspot, because it is rarely faster than 0.5Mbit/s or 500Kbit/s, which is about a tenth of the quoted maximum speed of an unenhanced 802.11b network connection.

There are several search engines that can be used to find the hotspot nearest to you - wherever you are in the world. Use hotspot finder or wireless hotspots as the search query to find them on the web.

And there's useful information at http://www.jiwire.com/ on how to connect to a hotspot, and even a WAP phone-based hotspot search that can be used while you're on the move.

How to connect to a wireless hotspot [using Windows Vista] -

http://www.pcadvisor.co.uk/how-to/network-wifi/12029/...

How to locate a secure wireless hotspot [using Windows Vista] -

http://www.pcadvisor.co.uk/how-to/network-wifi/12031/...

The information provided in those articles can also be used to locate and connect to a hotspot using Windows 7, because the networking in Windows 7 has not changed significantly from Windows Vista.

Beware of phoney laptop hotspots

For those of you who don't know, a hotspot is a place that allows a user equipped with a laptop computer that is itself equipped with a wireless network adapter to log on to the Internet, either as a free or as a paid-for service.

It can be difficult to determine if you have logged on to to genuine hotspot or not. All a con artist has to do is give the wireless connection installed on a laptop a plausible name or SSID (Service Set Identifier), and set it to be connected to on an Ad Hoc basis that connects computers equipped with wireless adapters directly to each other instead of via a wireless access point (a wireless switch). Then, when someone comes along to the bar or pub, etc., who is under the impression that it offers a hotspot to its customers, that person's wireless-equipped laptop will identify all of the open networks in the area. If the person decides to network with the con artist's computer instead of make use of the genuine hotspot, he or she won't be connected to the web. If the genuine hotspot requires users to enter a credit-card number before it allows them to use it, the con artist can create a phoney web page that allows those details to be stolen. If the unsuspecting person is able to make use of websites, such as the sites of banks, etc., they have been cached on the con artist's laptop computer. Any logon or account details that the person enters will also be made known to the thief.

Anyone who makes use of a hotspot is best advised to make use of them to access public websites only, but if you have to access a private account of any kind, you should make sure that the site address starts with https:// instead of just the http:// and that the secure yellow padlock icon appears on the bottom bar of the browser that means that the connection to the site is securely encrypted. You should also make sure that your wireless network settings are set so that you have to connect manually instead of automatically to wireless networks or hotspots.

To disable the ability of Windows XP to connect automatically to any available network or hotspot, double-click the wireless network's icon in the System Tray (Notification Area) in the bottom left corner of the screen. In the window that presents itself, click Change the order of preferred networks, and then click the Advanced button that appears under the Wireless Networks tab. Enable the Access point only option and disable the the Automatically connect option, and click on Close.

How to protect yourself at wireless hot spots -

"They can be an invitation to disaster, says Preston Gralla, who offers a surefire plan to avoid security breaches." -

http://www.computerworld.com/s/article/9007142/...

Visit the Networking Problems pages on this site to find out which networking problems have been covered.

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A single slow user can slow down an entire Wi-Fi network

A single user with a slow connection to a wireless network can significantly degrade the overall service to everyone using that Wi-Fi access station, new research shows. It has been discovered that if a single user's connection is slowed, perhaps because it is far from the access station, every user can suffer reduced data transfer speeds. 'That computer may degrade the nominal bit rate,' Duda told New Scientist. This is because of the way bandwidth is allocated to each user by the Wi-Fi standard's access protocol, called Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA). If just one person is unable to connect at the optimal speed, the CSMA/CA protocol reduces the maximum connection speed for every connection on the network. This ensures that any user, no matter what the access speed is, can obtain stable access to the network.

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High gain (hi-gain) antennas and wireless repeaters

One of the major problems with many wireless networks is the poor range of standard access points and routers. The problems can be solved by using a single-direction or omni-direction high-gain antenna that attaches to the connector of a wireless access point or network adapter. By increasing the strength of the signal, the wireless-network range, signal strength and performance are improved significantly.

You can buy a high gain antenna that extends the range of a wireless network or router in one direction or an omni-directional high gain antenna that extends the range in all directions. TheHawking [HAI6SDP] Indoor Hi-Gain 6dBi Directional Antenna is designed to extend the range of a wireless network in one direction. "Installation is simple. Hawking Hi-Gain Wireless antennas are designed to work with most Wireless Access Points, Wireless Routers and Wireless Network Adapters. By using the popular Reverse-SMA connector, the Hawking Hi-Gain Antennas can be used on most Wireless Devices."

Hi-Gain Wireless-300N Range Extender Pro -

http://hawkingtech.com/products/wireless/...

Here is a review of powerful Hawking Technologies high-gain single-direction antenna:

Hawking HA12W Hi-Gain 12dBi Directional Window Antenna -

http://www.pcadvisor.co.uk/reviews/network-wifi/1750/...

Entering a search query such as wireless network antennas in a search engine should provide you with links to other examples. You can also use it to locate information and vendors for the two products listed above or for wireless repeaters.

A repeater is used to boost a wireless signal if it is too weak to reach where you want it to reach.

When a wireless signal is first broadcast it is very strong. As it continues to travel away from its source, the signal strength weakens. The further from the source it travels, the weaker it becomes, until it loses its integrity entirely. This condition is called attenuation. A wireless repeater picks up the weakened signal, regenerates and rebroadcasts it, thus extending the range of the wireless network. Only recently have affordable wireless repeaters became available. For example, the D-Link AirPlus 900AP+ is a Wireless Access Point (WAP) that can also be used as a wireless bridge between networks. A recent firmware update has added repeater functionality to it as well.

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Bluetooth

Bluetooth technology also allows wireless communication between devices.

Bluetooth has a relatively short working range, which makes it less susceptible to electronic interference than is the case with 802.11 wireless systems.

Bluetooth wireless protocols have improved since first becoming available. It is now an ideal way of connecting small devices. By 2012, the Bluetooth protocol was up to version 4.0

The Bluetooth Technology Fast Facts website - http://www.bluetooth.com/Pages/fast-facts.aspx - says that engineers at Ericsson, the mobile phone company, invented it in 1994. The 1.0 specification was only released in 1999, because it took five years to get several electronics companies to agree to using the wireless protocol for short-range (up to 30 feet) voice and data communications.

Now, it is faster, provides improved security, increased range (up to 300 feet) and is even powerful enough to handle streaming music and HD video. Version 4.0 was released in 2010. It provides support for both high-performance and low-power applications. Bluetooth can be added to PC via simple USB adapters.

Windows 8 provides built-in support for Bluetooth 4.0. It can be added to earlier versions of Windows, which don't provide native support for it, by making use of a cheap USB/Bluetooth adapter. Here is an article on how to add a Bluetooth device to Windows Vista and Windows 7, which differ from each other:

http://www.windowsnetworking.com/articles-tutorials/windows-7/...

A web-search can be used to source many very cheap USB-based Bluetooth dongles, most of which are based on the still-usable Bluetooth 2.0 and 2.1. However, for less than U.S. $20, tiny, state-of-the-art Bluetooth 4.0 adapters, made by manufacturers such as IOGEAR and Medialink, are available that are backward-compatible with previous versions of Bluetooth. Moreover, the adapters can be upgraded to the latest version of Bluetooth by upgrading their firmware.

When making a choice between networking devices attention has to be paid to the speed at which they can transmit data. Wired network Ethernet adapters can transmit data at one, two or all three of the three available speeds measured in megabits per second (Mbit/s), not megabytes per second (MB/s): 10Mbit/s, 100Mbit/s, and 1,000MBit/s. The three theoretical maximum speeds for wireless network adapters that are never obtained in practice are: 11Mbit/s (802.11b), 54Mbit/s (802.11g), and 108Mbit/s (enhanced 802.11g).

However, when making a choice between Bluetooth wireless devices the speed as a determining factor is not as important, because usually the devices that use Bluetooth technology (cellular phones, keyboards, mice, wireless Access Points, headsets, global-positioning systems) don't have to transmit large amounts of data. Therefore, Bluetooth products don't work at different speeds. However, there is an important factor that has to be considered when purchasing Bluetooth devices: the range that you require of them.

Bluetooth devices are rated as Class 1 or Class 2 devices. Most Bluetooth devices are rated as Class 2 devices, which means that they have an operational range of of around 10 metres (33 feet). Class 2 devices have about ten times the operational range of Class 1 devices.

As usual, in order for a particular Bluetooth device to be able to perform whatever it does, which is called a profile, requires the correct software drivers to be installed. Some Bluetooth devices support several profiles. For example, a Bluetooth PC adapter, which broadcasts the wireless signal to Bluetooth devices, and is usually attached to a USB port on the computer, usually supports ten or more profiles. But a simpler device, such as a wireless headset for mobile phone, only needs to support two profiles.

Windows XP Service Pack 2 (SP2) includes new Microsoft Bluetooth drivers, which are easy to use. All you have to do is hotplug the Bluetooth device (plug the device into the computer while it is running) and Windows XP SP2 recognises it and places a Bluetooth icon in the System Tray. However, some devices won't work with the Microsoft driver. Fortunately, almost every Bluetooth adapter is provided with the older Widcomm Bluetooth software for Windows. To change from the Microsoft driver to the Widcomm driver, all you have to do is select the Bluetooth device in the Device Manager, click on it with the right mouse button and then click on Update driver, and follow the instructions to install the new driver.

Bluetooth technology makes it easy to set up a small network. Moreover, with more devices, such as phones and entertainment equipment becoming Bluetooth-compatible, the technology will probably eventually replace infrared wireless communication between such devices.

A new generation of mobile phones, global positioning system (GPS) navigation devices, and personal digital assistants (PDAs) use Bluetooth technology.

Mobile phones equipped with Bluetooth have built-in modems, and most of them support General Packet Radio Services (GPRS) data transfers. Data transfers using GPRS have a theoretical maximum speed of 54KB/s (kilobytes not kilobits per second), but in most situations this is more likely to be around 32KB/s. If you are connecting a mobile phone to a laptop computer, a Bluetooth adapter has to be fitted to the laptop, and the mobile phone has to have Bluetooth and GPRS data capability. In the UK, the payment of a monthly mobile phone tariff is required to make use of this service. You cannot use a pay-as-you-go connection.

With GPRS data transfers, you're only charged per megabyte (MB) of data downloaded. You aren't charged per minute while composing replies to e-mail, etc., only for the amount of data sent. The cost per MB of data transfers varies between service providers.

Most wireless equipment makes use of one small section of the electromagnetic spectrum - the Industrial, Scientific, and Medical (ISM) band - which occupies the frequency range 2,400 to 2.483.5MHz. Since this band is used by outside broadcast links, radio frequency identification, microwave ovens, 802.11b (Wi-Fi) and 802.11g wireless network equipment, and even by some types of lighting, interference can be an issue. To overcome interference, Bluetooth uses a very sophisticated frequency-hopping technology called Frequency Hopping Spread Spectrum (FHSS).

Bluetooth communication is secure provided that the user(s) switch on the highest level of protection that is provided, which, unfortunately, many don't bother to do. But, there are known security issues with some mobile phones, which should be investigated if you don't want thieves to be able to download your address book, diary, and calendar. You can find some useful Bluetooth links a little further down this page.

Because of its comparative slowness and lack of range, Bluetooth is not in the same league as any of the 802.11 wireless networking standards (802.11b - aka Wi-Fi, and 802.11g). Network Access Points (APs) are available, but they are designed to make it possible for PDAs, mobile phones, and notebooks to access the Internet; devices that are not ideal for copying data files or the rapid streaming of video, which are the functions that most users require of a network.

The official Bluetooth site - http://www.bluetooth.com/

The history of Bluetooth technology - http://www.ericsson.com/bluetooth

General Bluetooth information - http://www.palowireless.com/bluetooth

How Bluetooth Works - http://electronics.howstuffworks.com/bluetooth.htm

How to install and configure Bluetooth devices in Windows XP Service Pack 2. - To install a Bluetooth device, you only have to connect it. Microsoft Windows XP Service Pack 2 (SP2) includes drivers for many Bluetooth devices. If Windows does not recognize a Bluetooth device, you can still use it by using the generic software support that Windows includes, or you can use the driver that the device manufacturer provides. To add a Bluetooth device to your computer, you can use the Add Bluetooth Device Wizard. To configure a Bluetooth connection, you use the Bluetooth Devices item in Control Panel. -

http://support.microsoft.com/?kbid=883259

How to troubleshoot Bluetooth detection and connectivity problems in Windows XP Service Pack 2. - After you install Microsoft Windows XP Service Pack 2 (SP2), a Bluetooth device that previously functioned correctly in Windows XP SP1 and that supported Bluetooth wireless devices may not function correctly. This article discusses how to troubleshoot: • Bluetooth device detection issues. • Service detection issues. • Device detection and connectivity issues. -

http://support.microsoft.com/?kbid=883258&SD=tech

This is the official Bluetooth website - http://www.bluetooth.com/. It provides all the information you are ever likely to need on the subject.

Belkin make a wide range of Bluetooth devices, including USB adapters, laptop PC cards, wireless printer adapters, wireless networking Access Points, which can also include a print server, GPS navigation systems, keyboards, and mice. -

http://www.belkin.com/uk/

For more information on the subject, try using a suitable search query in a search engine, which most web browsers provide from their taskbars.

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Web searches

You'll also be able to find plenty more sources of information by entering search terms, such as: 802.11g, "windows networking" "peer-to-peer networks", and "home networking", etc., including or excluding the quotation marks, in a search engine.

Searches for "internet connection sharing", ics, etc., should turn up just as many informative sources. Note that you don't have to use quotation marks if there is only one term, and you don't have to use capital letters in a search term, because the search engines only use lower-case letters. There are many other tricks that can be used to refine a search. All of the search engines provide tutorials on how best to make use of them.