Wireless Networking can be extremely useful in the home for sharing files, printers and Internet connections between multiple computers where no cable network is available. However the topic of wireless networking and getting things set up and working properly (including securely) can be quite frustrating.
Setting up a wireless network is actually quite straight forward if you have done it before and more or less know what you are doing but when setting things up for the first time things can be a little tricky to understand. These days when signing up for an ISP you will more than likely be sent a wireless router which is already set up for you, but in these cases it is still quite important to have a general understanding of what is going on in case you have any problems or need to change any settings in the future.
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What Is A Wireless Network?
Anybody who has worked in an office type of environment or a workplace with a lot of computers will understand what a network is and how they are used. Basically a network is a collection of computers / computing equipment which is all connected together so they can share resources between one another. Usually in work environments this network equipment is connected together by what is called a structured cabling infrastructure. This is cables running round a building, usually terminated at wall sockets which the computers and computing equipment plug into. This cabling all runs to a computing office where all the cables are connected together, providing connectivity between the different pieces of equipment.
Wired Network
Although some companies are employing wireless networking equipment most wireless networks are set up in public areas (e.g. train stations, hotels etc...) and used in the home. In home environments this structured cabling system could be installed but very few people are prepared to rip their house apart or install cable conduits to install network cabling through their house to set up a wired network. This is where wireless networks can come in very handy.
A Wireless network is a set of computers or computing devices connected together using radio waves as the transmission medium. Instead of the network cards transmitting the data down a cable, the network cards wirelessly transmit the data using radio waves. So, in essence, a wireless network can be as simple as two computers with wireless network cards connected together with the same network settings, just for the purpose of sharing files and / or a printer. This type of wireless network is known as an ad hoc network.
Ad-Hoc Wireless Network
The other type of wireless network is known as an infrastructure network. This is where a central wireless access point acts as a hub and central point of administration for the wireless network. This usually transmits the network address and the computers, which are wireless hosts to the access point, connect to this just the same as they would if connecting with a wired hub.
Infrastructure Wireless Network
What Are The Different Standards About?
Wireless networking is based on a standard called 802.11(x). The (x), at the moment, is either a, b, g or n and represents the revision to the technology. There are other letters also assigned as (x) but for all intense and purposes these are the only four you need to worry about at present. The reason a common standard is needed for wireless networking is that many different manufacturers are making different equipment and if no standards were set you would not be able to use different manufacturers equipment with other manufacturers equipment.
802.11
802.11 Was originally introduced as a standard for Infrared transmissions and was capable of 1 or 2 Mbps and uses frequencies in the range of 2.4GHz. This standard was not very widely adopted at all.
802.11a
802.11a uses radio frequencies in the range of 5GHz and is capable of a maximum throughput of 54Mbps. The total range is around 100m outdoors, indoor range varies due to building materials but is usually around about a third to a quarter of outdoor coverage. Due to it's ability to be able to efficiently handle more connections than 802.11b, 802.11a was mainly adopted initially for business use and tended not to be used so much in the home market as the internal components used by 802.11a are more expensive so 802.11a Wireless Access Points are more expensive to manufacture.
802.11b
802.11b uses radio frequencies in the range of 2.4GHz and is capable of a maximum throughput of 11Mbps. The total range is around 110m outdoors, indoor range varies due to building materials but is usually around about a third to a quarter of outdoor coverage. 802.11b was the first wireless networking standard to get widely adopted as the Wireless Access Points and Wireless Network Cards that used this standard were cheaper to produce than the 80211.a variants.
802.11g
802.11g uses radio frequencies in the range of 2.4GHz and is capable of a maximum throughput of 54Mbps. The total range is around 110m outdoors, indoor range varies due to building materials but is usually around about a third to a quarter of outdoor coverage. 802.11g is a kind of extension to 802.11b as it uses the same frequency range and a similar transmission technology however it adds a new type of transmission technology to the top end to increase the available wireless throughput. As this standard was introduced it took over the mantle of most adopted standard as it is both backward compatible with 802.11b equipment and even after overheads are taken into account you still get a reasonable data rate over the wireless connection.
802.11n
802.11n uses radio frequencies in the range of 2.4 GHz and / or 5GHz and is capable of a maximum throughput of 248Mbps. The total range is around 160m outdoors, indoor range varies due to building materials but is usually around about a third to a quarter of outdoor coverage. 802.11n has MIMO capabilities written into the standard so it will be used on all 802.11n equipment. This makes the increased throughput possible as the extra transmitters allow for multiple simultaneous streams of data to be sent.
The maximum throughput figures quoted above are not the total speed your connection will run at, as it is in a wired network, as security protocols, signal strengths and other factors cause the actual data rate to be less than these figures. The actual data rates usually achievable will not be any more than half of the maximum throughput stated.
2.4GHz or 5GHz?
The difference between 2.4GHz Wireless and 5GHz Wireless is the radio frequency that the wireless signals use to transmit the data and both have their own advantages.
2.4GHz wireless is used by a great deal of household appliances like remote controls, microwave ovens, blue tooth devices, cordless telephones and many more. This means that as the technology has been widely used already the components needed for this range of radio signals have already been developed and the prices for these components are relatively cheap. This in turn makes it cheaper to manufacture Wireless Access Points that use the 2.4Ghz band. The downside to this is that in all likely hood the number of devices around your home which emit 'noise' that will effect your wireless network are plentiful and you may need to change the wireless channel just to stop the interference from your TV remote control affecting your wireless network signals.
5GHz wireless is not commonly used by a lot of wireless devices. This means that if you are in an area which has a lot of wireless networks close by and you are having difficulty finding a channel which will give you a half decent throughput, a Wireless Access Point which uses the 5GHz band may be very useful to you. The down side is that as the development of 5GHz radio devices is not as common as 2.4GHz devices this equipment is generally more expensive.
MIMO - Multiple In, Multiple Out
MIMO is a way of increasing Wireless coverage and was first used in newer 802.11g Wireless equipment but is included as part as the 802.11n standard. MIMO works but using multiple transmitters and receivers as a way to increase range and speed. The extra transmitters make the Wireless Access Point capable of sending and receiving multiple streams of data at the same time.
What Do I Need To Set Up A Wireless Network?
To set up a wireless network you first need your computers to have wireless network cards. The other piece of equipment usually used, but not essential, is some kind of Wireless Access Point. These can come as a standalone unit or as part of another piece of equipment, like a router. The equipment you already have will determine what type of product you need.
Wireless Network Card
Wireless Network Cards can come in many different forms. All computers that want to connect to a wireless network must have a wireless network card of some form attached to the computer. These wireless network cards can come as part of the motherboard like in a laptop, as a removable card like a USB or PCMCIA card or they can come as add-on cards like a PCI card. A small selection is displayed on the right.
Wireless Access Point (Standalone)
A Wireless Access Point is a device which will only send out the Wireless signals and does not carry out any other networking tasks. These are usually used on networks which already have networking infrastructure present (e.g. Servers providing DHCP / DNS services, wired routers etc...). This type of network could include a company network which just needs to add wireless connectivity to the network. They are also used when trying to increase the coverage of a current wireless network.
Wireless Routers (Or Wireless built in to another device)
The more common equipment used in home networking to provide a wireless network is a wireless router which, as already stated, you usually get provided with when you sign up with a new ISP these days. If not they can be purchased from your local PC shop (However if this happens to be PC World, don't just take the advice of the sales staff as once or twice I have noticed their recommendations have been for products which are coming to end of life cycles and not the best product for the job they have available).
These are usually used in home or very simple networks and they provide less equipment to clutter up your home and do not need to provide a large number of individual connections so are not being pushed too hard. They will have in built networking services like DHCP, DNS, firewall's etc... so provide the entire infrastructure for your home network. They are usually highly configurable so can be set up for a wide variety of network models.
What Settings Do I Need For My Wireless Network?
SSID
SSID stands for Service Set Identifier and is just the name of your wireless network. When you purchase a Wireless Access Point it will usually have a factory set SSID which you can use to identify your wireless network from a neighbours or you can change the factory set SSID to one which is more personal to you. You will usually have an option to hide the SSID which will mean that to be able to connect to your wireless network you will need to type in the name of the network rather than just select it from a list of available networks, as it will be hidden on the list of available networks.
There is a common myth that hiding your SSID makes your wireless network more secure, this is not the case as it is extremely straight forward to find the hidden SSID. All hiding your SSID achieves is to disallow the non computer savvy person from telling that there is a wireless network using this channel, which may mean you are using the same wireless channel as a neighbour which could affect signal strength and speed.
Wireless Channel
In the UK wireless networking devices can use 13 different wireless channels, however some of these channels overlap slightly. If possible it is best to use either channels 1, 5, 9 and 13 as these channels do not overlap, but if you are living in an area which has a lot of wireless networks close by you may need to use one of the channels which slightly overlaps to get a good wireless connection. Some Wireless Access Points have an option of Auto channel select which will usually choose the clearest channel to use each time the access point is restarted or it will change the channel if the current channel being used becomes congested. Although I haven't used a lot of wireless equipment lately my feelings on the early implementations of the Auto channel selection is that it caused more problems than it solved, although the problems this used to cause may have been sorted by now.
Security
With regard to security you need to make two choices. Firstly you need to choose which type of wireless security you are going to use as there are various different types. These different methods of wireless security are run through in more depth in the next section.
The other thing you need to choose is the encryption key or pass phrase which is used to encrypt the data being sent wirelessly. More information on these keys and pass phrases is also dealt with below.
Encryption (Security)
If you are running a wireless connection with no security it is very easy to intercept packets and decipher them to obtain personal details (think on-line banking to understand how important this is) as they are sent in clear text. Also if you are running a wireless connection without any security your neighbours may be able to connect to your wireless network and use your Internet connection which can use up your monthly download allowance, is in itself a breach of most ISP's terms and conditions (as it's seen as sharing your Internet connection with another premises) or even worse, if your neighbours are doing something against the law (i.e. distributing child porn, spamming etc...) this will be traced back to your Internet connection. This un-secured wireless connection could also be used to access information on your networked computers if these people know what they are doing.
Encryption basically is a way of being able to scramble the data up so you can transmit it in a way that nobody can understand it but do it in a way that the intended receiver knows how to un-scramble the data to be able to use it. This is usually done by applying some kind of shared key or digital certificate to an encryption technique which scrambles the data up so the only people that can use it are the ones that know the shared key or are the holders of a relevant certificate on their machine.
Security methods employed by wireless connections have evolved over time as newer encryption methods have been produced. Both the access point and the client must be using the same type of encryption as well as having the same encryption key to be able to connect. Below is a list of the different types of wireless encryption being used today.
WEP Encryption
Wireless Encryption Protocol (WEP) was used with the first breed of wireless networks. It works by using a shared 64 or 128 bit key between the client and the access point. i.e. both the client and the access point have had the same key typed in to their client program. This key is usually a hexadecimal group of characters.
The client first asks if it can authenticate with the access point. The access point then sends a clear text packet to the client. When the client receives the packet it uses the shared key to encrypt the clear text packet and sends the encrypted packet back to the access point. When the access point receives the encrypted packet it uses it's version of the shared key to decrypt the packet. It then compares the decrypted packet with the original packet it sent to see if it matches.
The problem with this method of encryption is that if you can snoop these first four packets you have the un-encrypted packet and the encrypted packet so you may be able to work out the key. Also because the key is always the same if you can capture enough encrypted packets it is also possible to work out the shared key.
WPA-PSK Encryption
Wi-Fi Protected Access - Pre Shared Key (WPA-PSK)
was the next iteration of encryption to be used. WPA-PSK still uses a shared key but it uses a process called Temporal Key Integrity Protocol which continuously changes the key. So the collection of packets for analysis to try and work out the encryption key is cancelled out as the key keeps changing.
WPA encryption was a stop gap measure while a new encryption process was being ratified, which eventually became WPA2. It was put in place to try to overcome some of the basic security flaws in WEP.
WPA-EAP Encryption
Wi-Fi Protected Access - Extensible Authentication Protocol (WPA-EAP) is WPA encryption which uses some kind of 802.1X security server which is used to centrally distribute keys or certificates. This model is usually used by large business's to centrally manage their wireless network, although it is also used in public hotspots as a way of being able to charge customers.
WPA2 Encryption
WPA2, also some times referred to as WPA - Advanced Encryption Standard (WPA - AES), is the final ratification of the IEEE 802.11i security standards. 802.11i is not a type of wireless mode, it is the process that was started to overcome the problems with WEP. The early pre-releases of the 802.11i standard is what WPA is based around, WPA2 is basically the final standard of 802.11i.
Because of this WPA2 uses the same Temporal Key Integrity Protocol to encrypt data but it also uses new algorithms, AES and CCMP (Counter Mode with Cipher Block Chaining Message Authentication Code Protocol) as ways of keeping the data secure.
WPA2 is the most secure type of encryption used today so it is the option you should take if available to you. Microsoft Windows XP, Vista, Mac OSX and most commonly used versions of Linux now support WPA2 and pretty much all wireless network cards and access points sold these days support WPA2.
What Client Software Should I Use?
Client software is the software that you use to set up your wireless connection. Most operating systems these days have their own in built wireless client but you will also get a wireless client with your wireless network card and if you needed more in terms of corporate administration you can buy specialized wireless client software. If you are using a client that came with the wireless card or a specialized client application you should refer to the instruction for information on setting these cards up. Whichever you use is up to you but you should make sure you only have one on at a time.
Although not always the case, the best software to use should be the one that comes with the wireless card as it should be suited to the actual hardware rather than being a more generic client. Most people, however tend to use the one that comes as part of their operating system and these usually work perfectly well.
Just be sure that the drivers for the actual wireless network card itself are compatible with the operating system you are installing them on and, if possible, try to get a copy of the newest drivers for your wireless network card from the cards manufacturers web site.
