Traditionally Computers have been put together in Networks with cables
using hubs or switches to join them all together. Wireless Networking
is exactly the same in concept, except instead of the Ethernet cards &
cables we have Wireless Network cards, and instead of hubs and switches
we have a Wireless Access Point or Wireless Router.
Convenience & Portability.
Whilst cables are generally faster for transferring data between computers at this stage, wireless equipment has come down so much in price that it is now a serious contender and often cheaper overall than running cables. Apart from DIYs, average cost per PC to Cable, including sockets, cable and Network card would generally run somewhere between $140-250.00 per PC. In comparison, Wireless Network Cards start at around $50.00 and nothing else is required apart from a Wireless Router or Access Point.
Where wireless has its limitations is in its range, penetration, comparative
speed and its security considerations.
Range wise, most WAPs and Wireless Routers with standard 2-2.5 dbi antennas
will usually go up to around 100 metres with clear line of sight.
Add a wall or three in the way though and this drops considerably. A general
rule of thumb would be 2 to 3 timber framed plaster walls within around
30 metres for most standard products indoors.
Method 1. Getting the most out of what you have. The first method is to check you've got everything working as well as it should be. Quite often you may be getting interference from other wireless devices from neighbours or devices like baby monitors (a rare one but it happens). Changing the radio channel (there are 13 to choose from in Australia which you'll find under the advanced wireless settings in your device) and trying different positions for the router or WAP can make a great deal of difference. There's quite a good thread in the Billion forums with lots of helpful tips and links for getting the most out of your Wireless performance.
If your area is swamped with neighbours' WAPs hogging all of the radio channels already you might consider going for a 5GHz WAP or Router instead of the more common 2.4GHz products. Products advertised as "dual band" have 5GHz capability (some will broadcast on both 2.4 & 5GHz bands simultaneously while others are switchable only). Bear in mind you will also need 5GHz or dual band adapters in your PCs and other WiFi devices to work with the WAP though.
Shane also emailed me with a quick and simple change he made to his MR814
Router utilising a saucepan lid to boost the signal (in effect creating
a DIY Parabolic
grid antenna). In his words -
Method 2. Fit bigger antennas. This is where purchasing a router or WAP with removable antennas comes in handy. Most routers and WAPs are fitted with 2 or 2.5 dbi antennas by the manufacturer. As a general rule of thumb upgrading to 5dbi antennas will improve things by roughly 10-20%. Stepping up to 7dbi antennas will generally yield a similar 10-20% improvement over a 5dbi antenna. (I use the terms "generally" and "roughly" here quite deliberately because there are no guarantees when it comes to wireless and the mileage will vary from location to location). If you need any more than a 7dbi antenna I'd consider adding more WAPs or repeaters instead.
Here you can see the difference in size between 2.5, 5 and 7 dbi antennas:
Click here for the range of antennas available from my online shop.
Note: If your router or WAP has more than one antenna you will need to upgrade all of them for it to work properly. Bear in mind too that antennas don't all have the same type of connector so make sure you do your homework first and buy antennas that will fit. 75% of routers and WAPs like most (but not all) Billion, Draytek, Netgear & D-Link products use an SMA connector. The second most common type is the larger TNC connector which will be found on many (but not all) Cisco products. The third most common type is the N connector which sometimes comes up on some routers or WAPs but is more commonly found on pigtails (extension cables for antennas).
Method 3. Amplifiers and high TX WAPs
Some WAPs and routers also allow you to alter the transmission power output. While these are usually set on their maximum by default anyway that's not always the case and it's worth checking out to see if you can squeeze a little more out. However, keep EIRP in mind, especially if you start hacking stuff and fiddling with high gain antennas. There are laws that are enforced and fines that will be payable...
There's also Routers and WAPs available with higher than usual transmission power (most standard WAPs have less than 200mw). Most products advertised as suitable for outdoor use also have higher than usual transmission power.
Amplifiers for smaller home-type applications are fairly thin on the ground (at least from the distributors and manufacturers I generally deal with) but there is the odd one like the Netcomm NP562 wireless booster (sadly now obsolete) which boasts 500mw of transmission power.
If it was my house, I think I would be more comfortable installing multiple WAPs or repeaters with under 200mw outputs rather than install something that might warm my coffee and make my hair stand on end everytime I walked past it. (See possible health risks in 1.16 below.)
Method 4. Add more WAPs. Adding more WAPs (joined together with cables back to a switch) is a simple way to extend wireless range. If you configure them to broadcast on different radio channels but use the same SSID and encryption, any roaming PCs will automatically connect to the strongest signal they can find should they drop out from another WAP.
If running a cable is a problem, another way to provide a physical connection to a second WAP is to use a Homeplug adapter.
Method 5. Wireless Repeaters/Range Extenders. Wireless repeaters can receive a wireless signal and rebroadcast it at the same time. This means they don't need to be cabled into the network. This can be a huge advantage but they do take a bit of skill to configure (read: right royal pain) and compatibility between different brands and models is a very common problem. The exception to this is products advertised with cross-brand compatibility such as most of Netgear's Universal Range Extenders. In all cases check the manufacturer's website for mention of cross-brand compatibility or a compatibility list. If the manufacturer doesn't mention it and doesn't have a list then assume it will only be compatible with another of the same model. If in doubt, get it confirmed in writing from the manufacturer before you purchase.
Note: I made it easy to find WAPs with repeater capability on my online shop by searching the word "repeater".
To check out the differences between repeater modes like WDS, Repeater, Universal Repeater, Client Bridge etc, check out this table at DD-WRT.
The Bigger Stuff. Outdoor Bridges and larger Multi-WAP Networks:
Outdoors, range can be quite remarkable with the right equipment and no obstructions. For example Ips-Mesh have been experimenting to see how far they can get a wireless link without using amplifiers and so far they've managed an amazing 60km.
I had a bit of a hand in bridging two offices approximately 1.5 km apart wirelessly several years ago and it worked quite well. The equipment used there would be pretty much what would be required for any sort of outdoor wireless link once it goes beyond the range that standard antennas can handle but every situation is different so it's well worth talking to someone in the know or having a professional wireless consultation performed at your premises.
EnGenius are happy to have a chat and recommend the right products for everything from a small outdoor bridge right up to a full commercial installation and direct you back to my online shop to purchase the hardware.
If you're on a budget and handy with a soldering iron you can make your
own directional antennas (Use Google to find heaps
of examples). Wayne reports his cheap outdoor wireless bridging experiences
using DIY antennas - "I've got a couple of Minitar APb's on a
link 0.8km that are performing very well on quite small
BiQuad aerials. I have a moderate cable length at one end 10m CNT400
cable with pigtails. The other end has 5m of 9006 Cellfoil cable with
no pigtails or joins, terminated directly to a rev SMA connector."
Larger multi-WAP networks.
Too many WAPs on one network eventually becomes a bad thing. In this situation some WAPs may become overloaded and behave erratically while others will get very little use at all. Traffic bottlenecks, dropouts and interference caused by WAPs overlapping will drive users and admins crazy. There are a couple of solutions for this kind of thing.
The first are wireless controllers like D-Link's DWS series of switches and controllers and Netgear's WFS709TP & WC7520 which can work with "thin WAPs". A thin WAP is basically a dumb device that receives all of its settings and instructions from a controller. The controller decides how to distribute the load and where the overlaps happen and so on.
The second technique is a "wireless mesh" such as the EnGenius M Series of products. (This series of Youtube Videos provides some great introductory information). The WAPs in this case are linked together in a kind of hive after being configured and monitored from a software application installed on a PC. One big advantage with the EnGenius mesh system is no cables are necessary (the WAPs will of course still need power though).
I can't give comprehensive product advice or act as a consultant for either
outdoor wireless bridging or multi-WAP networks (what I've written here
is pretty much the extent of my knowledge). However, EnGenius will do
online consultation and I can arrange an onsite wireless survey with
D-Link or EnGenius on request.
Cables are faster (at the time of writing) and more secure, but may involve
drilling and aesthetic changes to the premises to get the cables where
they need to go.
Plans and speeds from ISPs vary substantially so these are just rough ballparks.
Now, if we compare these speeds with the advertised WiFi speeds we can see we've got it pretty much covered:
* WiFi speeds advertised by the manufacturer and the Link Rates reported on your PC are full duplex (ie data flowing in both directions simultaneously) and don't factor in the unavoidable overheard in wireless. Actual throughput speeds, ie data travelling in one direction (for example transferring a file from one PC to another), are much less. Speed will also vary based on the equipment, encryption method, signal strength, interference from other wireless signals and so on. My own throughput tests** rarely came up with more than 40 - 55mbps on my home 11n router (which is half than the 80mbps mentioned in the chart above).
** My tests were done using QCheck,
2710Vn with standard 2.5dbi antennas and WPA2/PSK AES encryption,
a desktop PC with a Billion
3011n USB adapter in the floor above, and a laptop one room away with
Or, the figures above in graph format (Blue is the more likely experience.
Getting up into the pink section is exceptional and rare):
There are other considerations too besides the Internet download speed. Where the faster 11n (N300) wireless gear also comes into its own is in sending and receiving files across the local network and/or accessing a shared database on a central server, particularly if there are several Wireless PCs in operation at any given time. In other words, fastest is best. :)
Tip: For help converting bits to Bytes or megabytes per second to kilobits per second and so on, check out the Numion Unit Convertor here.
You will need a Wireless Router or Access
Point* and a Wireless PCI Card or USB
Adapter for each Desktop PC you want to be wireless, and a Wireless
PCMCIA card or USB Adapter for each Laptop PC you
want to be wireless. Bearing in mind that just because you're installing
a Wireless Router, all of the PCs don't necessarily have to be Wireless.
Wireless Routers also usually include a built-in 4 port switch so you
can run a combination of wired and wireless PCs on the network. It makes
no difference to Network browsing whether a PC is wireless or wired and
you'll probably find that you've got at least one PC that lives right
beside where the Router is, so there's not a lot of point making that
one Wireless if it never moves and a 2m patch lead and $20.00 non-wireless
Network card will do the trick.
It's generally recommended that you stick with the same brands if possible
as there may be some features that a manufacturer has introduced for their
range that may not be usable if you mix the brands up (eg D-Link 256 bit
No, but you're better off if you do. A Wireless Router or Access Point
will provide better range and reliability than an Ad-Hoc
Network, plus it's a lot less complicated to install.
If your PC is more than 2 years old, carefully check the Wireless adapter
manufacturer's specifications for minimum system requirements before you
buy. Software wise, in most cases a minimum of Windows 98 Second Edition
(not 1st edition) is required to be able to install a wireless adapter
but there's also hardware issues with many products. Eg Many PCI cards
particularly with Prism 2 & Broadcom chipsets found in many Netgears,
D-Links, Minitars, SMCs and more, require V2.2 PCI compliant Motherboard
usually found in boards P3 and above, running in 3.3V mode. (5.0V PCI
mode won't work.)
You should generally stick with whatever your Macintosh supplier recommends,
but if you're a DIY type and feeling adventurous, check out the
OrangeWare drivers. These offer driver support for other manufacturer's
wireless adapters so you will probably save a few dollars there, but there's
also support for 108mbs equipment which you can't get from Apple just
Wireless Broadband is a term used to describe 3 quite different services.
802.11a: runs in the 5GHz frequency range and will allow data speeds of up to 108 mbps The shorter wavelength of the 5GHz frequency greatly reduces its range and penetration but it comes into its own in areas where it might be overcrowded or have other equipment (eg medical) operating in the 2.4 GHz range. Its lower performance and comparatively hefty price tag have made it fairly unpopular in Australia and it's now quite rare to see products on the market utilising the 802.11a standard.
802.11b: operates in the 2.4GHz frequency range and was an advance that led to wireless networking becoming popular and viable in Australia. It promised throughput speeds of 11 mbps but as with all wireless technologies you can at least halve the manufacturer's figures for true throughput results using a network tool such as Qcheck. Range can be anything up to 100 metres with clear line of sight with most products out of the box but can be extended substantially with aftermarket antennas and boosters.
802.11b+: operates in the 2.4GHz frequency range and was a variation of 802.11b chipset used by D-Link in particular. It doubled the throughput figures but would fall back to plain 802.11b speeds when used with other wireless standards including the modern ones like 802.11g & n. See also FAQ 2.15 below.
802.11g: operates in the 2.4GHz frequency range and took wireless speeds up to 54 mbps and with a bit more throughput to play with it effectively extended the range a little bit too. It remains a popular and cost effective choice.
802.11g+: operates in the 2.4GHz frequency range and was a variation on the 802.11g chipsets that effectively doubled the data speeds. However, when used in conjunction with 802.11g or n products it will fall back to standard 802.11g speeds. See FAQs 2.16 & 2.17 below.
802.11n: comes in many different variations as detailed below, but when someone refers to a product as being "802.11n" or "11n" they would usually mean it's the N300 single band version.
N150: operates in the 2.4GHz frequency range and is a cheaper, scaled down version of 802.11n, allowing speeds of up to 150mbps when used in conjunction with 802.11n wireless adapters.
Note: "High-powered" USB adapters (ie 200mw or above Vs under 100mw on most standard products) like the EnGenius EUB-9603H, Planet WNL-U555HA, TP-Link TL-WN722N and TL-WN7200ND are available in the N150 category.
N300 (single band): The most common version of 802.11n WiFi operating in the 2.4GHz frequency range with data speeds of up to 300mbs.
Note: Higher gain 2.4GHz antennas are plentiful and reasonably priced making 11g, N150 & N300 products the ones to go for if you're likely to need to boost performance or for outdoor wireless applications.
N300S* Selectable Dual Band: Products with this variation of 802.11n can broadcast in either the 2.4GHz frequency range or the 5GHz frequency range (but not both at the same time) with data speeds of up to 300mbs on either frequency. Handy to have if you find yourself in an area swamped with neighbours all with their own WiFi 2.4GHz broadcasts drowning yours out.
* I made up the term "N300S" to differentiate these products from the plain 2.4GHz only N300 standard on the OzCableguy Online Shop.
Note: Higher gain dual band 2.4GHz + 5GHz antennas are difficult to find but there is the odd one around like the Planet ANT-OM5A.
N450: Is a variation of simultaneous
dual band (2.4GHz and 5GHz) 802.11n wireless similar to N600, usually
with 150mpbs on the 2.4GHz channel (ie N150) and 300mbps on 5GHz.
N600 Simultaneous Dual Band: Products with
this variation of 802.11n will broadcast in both the 2.4GHz and 5GHz frequency
ranges simultaneously. While the "600" in N600 might indicate
600mbps speeds, N600 is better thought of as 300 + 300. ie It allows the
option to connect some devices to the 2.4GHz frequency and others to the
5GHz frequency to provide a better distribution of load and bandwidth
across the wireless network.
N750: Is a variation of 802.11n with 300mbps on the 2.4GHz channel and 450mpbs on the 5GHz channel.
N900: Is a variation of 802.11n with 450mbps on the 2.4GHz channel and 450mpbs on the 5GHz channel.
802.11ac (also known as Gigabit WiFi, "11ac" or just "AC"): Is the latest WiFi technology released onto the market mid 2012. It operates in the 5GHz band and is backwards compatible with existing 11n 5GHz devices. Most 11ac routers and WAPs have also been released as dual band devices with a 2.4GHz chip included to allow connectivity of 11n 2.4GHz devices. More detail about 802.11ac here.
"11ac" isn't just "11ac" though. There's some
notable variations in the technology. Some feature 300mpbs on 2.4GHz while
some are 450mbps or even 600mbps, and some are 867mpbs on 5GHz Vs 1300mpbs
on others. Products are generally advertised using the combined speed
of the 2.4GHz and 5GHz broadcasts added together, even though it's not
actually possible for a PC to connect to both at once so the connection
speed will actually be at whichever channel the PC is connected to. eg
A PC connected to the 2.4GHz channel on an AC1200 (300/867) device will
show a connection speed of 300mbps. If it's connected to the 5GHz channel
it will connect at 867mbps (provided the PC has a wireless adapter installed
that is capable of at least 867mbps at 5GHz).
Here's a quick table showing the more common 11ac marketing names and the speeds available in either channel.
*AC3200 has three broadcasts (SSIDs). One at 600mbps on 2.4GHz and two at 1300mpbs on 5GHz. Technically it offers no real speed advantage over AC1900 but could be handy to split up a network with a lot of wireless devices so each device gets a larger slice of the available wireless bandwidth pie.
Note: Dual band Wireless adapters, whether marketed as N450, N600, N750, N900 or 11ac, are always selectable, not simultaneous dual band. ie they will connect at either the 2.4GHz or 5GHz frequency, not both at the same time. It is not possible for a PC to connect to both frequencies at the same time.
The table below shows connection speeds you can expect when mixing and matching products with different wireless standards. (Bear in mind these are only the link rates a PC will report. Actual throughput will be more like something between 20-40% of these. See FAQ 1.6 for more info).
For more information see IEEE 802.11 in wikipedia.
The table below shows some common uses of frequencies across the Radio Frequency spectrum.
Not likely, although it has been known to happen occasionally*. I know
of one report where a Wireless network was known to drop out whenever
a certain cordless phone rang, but I've installed and sold hundreds (maybe
thousands) of wireless products and it has never come up for me personally.
I have a cordless phone less than a meter from where I test wireless Routers
and WAPs, and although frequencies vary between brands and models of cordless
phones, if it was going to be a common issue it would have come up frequently
by now. In any case, wireless products come with the ability to change
the Wireless channel so you can move it to a different frequency if you
do strike a problem.
* Wayne reports "I have a Panasonic KX-TG2570ALS that caused my wireless to drop out on a connection to a laptop. If the phone is closer than 3m while in use it adversely effects the laptop's wireless connection. This is a bit of a downer because I was using the laptop to provide information while on the phone outside on the patio. It meant moving in to a fixed line phone to regain the network connection."
In a nutshell - no.
Yes, all that's needed is to disable the router features. This involves
Note: For the difference between a Wireless Router and a WAP see the Wireless Products section below.
Ad-Hoc is peer to peer networking. ie The Wireless PCs connect to each
other rather than to a central access point. eg PC1 connects to PC2, PC2
connects to PC3 etc. Great for setting up a quick wireless LAN to share
some files with others, but on the downside it gets very difficult to
manage and throughput becomes worse and worse as the number of wireless
devices increases. It's also very difficult to bridge to the wired LAN
this way and/or setup Internet Sharing with more than one other wireless
Infrastructure is the most common form of Wireless Networking where all of the PCs connect to a central Access Point.
dB is decibel. dBi is a comparative ratio and refers to "Decibels
compared to an isotropic* antenna".
* An Isotropic Antenna is a theoretical "standard" antenna which has an equal broadcast of 360° in all directions.
dBm is another ratio and is decibels compared to 1 milliwatt which is an industry term used to describe the transmit or receive power of a wireless device.
Effective Isotropic Radiated Power.
Many people conclude that antenna gain is the power of the antenna, but
they'd be wrong. The only way to make an antenna "more powerful"
as such, is to increase the amount of power feeding into it. Gain is more
correctly thought of as the characteristics of the antenna as a relationship
(expressed in dBi) to a theoretical "standard" antenna which
has an equal broadcast of 360° in all directions.
Note 2: What most people want to know is "How does this equate to distance?". Hopefully this description of gain will go some way to explaining why I tend to run away screaming from that one. The answer is the proverbial "How long is a piece of string?". There's the transmission power of the WAP, environmental variables and the receive power/EIRP at the other end, the Fresnel Zone etc etc, so it's just impossible or at least extremely difficult (at least for me) to answer accurately. The best answer you'll probably get from anywhere is "the closer you can get to the maximum legal EIRP you can get, the more likely it is to work" but as to how far the signal can go in terms of metres or kilometres is anyone's guess. However, most technicians who specialise in Wireless will have a selection of products they commonly deal with and they'll have a good idea of what to expect from these in a given situation, but quite often it's a trial and error process (erring heavily on the side of overkill if the gear has to be purchased up front).
Named after the scientist who first documented it, Dr Clarence Zone. (Sorry, couldn't resist that one.) It's actually named after 19th century French physicist Augustin-Jean Fresnel and defines the line of sight area, taking into account any obstacles. Basically it's a scientific way of working out what antenna gain and mast height will be required to get optimum signal from one wireless point to another.
Zytrax have a useful Fresnel Zone calculator. Basically you tell it the distance you need to cover all up and then the distance to the first obstacle, and it works out what mast height you need for optimum wireless signal. It also takes into account curvature of the earth and so on, so it's not the kind of thing that will be useful for a simple home Network, but I think it's worth mentioning here for the sake of explaining Wireless signal characteristics a bit better. eg In my dodgy diagram above we can see that simple line of sight could have been achieved with a much shorter mast but then the house in the middle would have been extending into the Fresnel Zone and adversely effecting wireless performance. The same principle can be applied if, for example, there was a bank of metal filing cabinets in between the Wireless Router and the PC the signal had to travel to, or if there are too many walls in between. Higher is better in this case, so maybe moving the Router to the second floor or up in the roof will service the area you need to cover much better. I have a high set home with the living areas upstairs so I find I get better overall coverage by having the wireless router on the bottom floor.
Milliwatts. The unit of measure used to express the transmission power of amplifiers.
Service Set Identifier. Also sometimes called BSSID and ESSID depending
on what particular Network subset it is identifying, but for us laymen
we'll just ignore all that and assume they all mean the same thing.
All Wireless Routers and WAPs have a default SSID (and it isn't hard to find out what they are, even with a quick Google). Many experts recommend for security reasons (or just to have some fun with the neighbours) to change the SSID to something else. You can disable the SSID broadcast to make it even harder but some WiFi devices will not play ball in this case and even if they do it's somewhat painful because it means creating a profile in your PC's Wireless configuration utility specifying the SSID. With that being said though, the advantage in doing hiding your SSID is that it makes it that much harder for an unauthorised person to connect to your Wireless network. The theory being, if they can't see you, they can't try to connect to your WiFi network. However, it's not regarded as a proper security precaution as a hardened cracker may be able to capture this information (eventually) from the signals your Wireless PC sends out while looking for the WAP or Router, or use the rogue Access Point method to get one of your PCs to connect to it and give away the information.
A wireless configuration utility is an application that runs on your Wireless PC that is used to scan for WAPs to connect to and to configure the wireless security settings. Most utilities have the ability to create "Wireless Profiles" so you don't have to go through configuring all of the Security and Network information each time you reboot the PC.
With the popularity of Wireless, Microsoft decided to include a Wireless
Configuration Utility into Windows XP which they named the Wireless
Zero Configuration utility. Great stuff, however it can be a bit of
a pain because the Wireless Adapter manufacturers usually include their
own Wireless Utility with the drivers, and running both at the same time
will usually cause some bad behaviour like being unable to locate or connect
to a WAP or Router, or suffer from frequent dropouts.
Wireless Distribution System.
Another possible trap. One other issue to bear in mind
is the wireless security options available in WDS mode. For example the
Netgear WPN824, WG302 & WG602
products only have a maximum of WEP available as a security option in
WDS mode. (See this
Netgear Knowledge base article). For WPA or WPA2 wireless security,
a higher end product such as the WNR3500
See also Wireless Repeaters below.
Wireless Local Area Network. (Your Wireless Network.)
A Wireless Hotspot is a place where you can BYO wireless PC or PDA and
get Internet Access. Many Cafes now provide a Wireless Hotspot and the
service can be either free or paid or reserved for customer use.
802.11B Enhanced is a variation of plain old 802.11B 11mbs wireless which
allows double (22mbs) Wireless data speeds. ( True throughput is closer
to 8-10mbs which is still faster than most Broadband Internet connections.)
XtremeG is D-Link's version of 108mbs Wireless which is marketed under
various other names with other manufacturers. It is fully backwards compatible
with normal 802.11B and 802.11G products but will fall back to these slower
speeds if used with these slower products. To get the 108Mpbs wireless
you must use all XtremeG products on your Wireless Network. One 54mbs
product on the Network will cause the whole Network to operate at 54mbs.
It's also not very friendly with 802.11B Enhanced (22mbs) products. These
will usually fall back to 11mbs but sometimes won't work very well at
all with poor range, really slow speeds and poor reliability sometimes
Same as D-Link's XtremeG above.
Speedbooster is Linksys's version of enhanced 802.11G. While it only
promises an increase in speed of up to 35% which is a bit slower than
the Netgear & D-Link versions, it doesn't use channel bonding so isn't
restricted to any particular Wireless channel. It is also copes with mixed
modes (combinations of standard 802.11G and even 802.11B products) better.
Netgear's XR (Extended Range) technology doesn't actually boost the signal
as the name might indicate. What it does is allow reliable connections
at weaker signals by trading distance for throughput. In other words,
as the distance increases (or signal strength decreases) it steps the
speed back rather than just dropping out. It works very well and is available
on most Netgear 108mbs products including WGT624,
WG111T, WG311T, WG511T, WG511U, WAG311 & WAG511.
MIMO stands for Multiple Input Multiple Output and is a new Wireless
technology characterised by 3 or more antennas.
an enthusiast hobby that involves driving around in a car (or Taxi, Bicycle,
on foot etc) with a wireless Laptop or PDA and recording the Wireless
Access points discovered. There is obviously a less than honourable element
that will try to utilise any Wireless connection they find to gain
"free" Internet access (at the owner's expense) or steal
software/registration codes or just poke their noses where they don't
Every device that connects to a Network (or the Internet) has a unique identifying tag called a Mac (Machine) address. Mac address authentication can be set up on a Router or WAP to either allow only certain specified Mac addresses (and no others) to connect, or to deny access to certain Mac addresses.
To find the Mac address of your PC's Network Card:-
It's actually not bad at all and will cover most situations quite well, plus it has a minimal overhead so is least likely to impact on the Wireless network performance. Where it has a weak point is that it is possible for a hacker to eventually capture enough data floating around the airwaves, or use the rogue Access Point method to be able to copy the Mac Address of an authorised PC to gain access to the Wireless Network. In most cases the give-away that this has happened will be a PC suddenly and mysteriously being knocked off the Network.
Wireless Equivalent Privacy. The most common method of securing a wireless
network where connection to a Wireless Access point is achieved by specifying
a special key which is a string of random letters and numbers. Similar
in concept to a username and password, WEP keys vary in complexity from
64 bit up to 128 bit and even 256 with some products.
The Access Point or Router will have a section where you can switch on
WEP and specify a key by use of a passphrase.
Note: If you only have a Wireless PC to work with while setting up security, remember you need to do the settings on the Router/Access point first and then your PC second, otherwise it's much the same effect as painting yourself into a corner...
Here is a quick step by step example using the
basic Billion 5100W and the WEP key generator at http://www.andrewscompanies.com/tools/wep.asp.
WEP is OK for stopping neighbours and other general sticky beaks close enough to pick up your wireless signal from getting into your network and/or taking advantage of your Internet connection. However, it can be cracked in less than 3 minutes by those with the knowledge and tools so I wouldn't call WEP an effective security method by itself any more.
WPA is the latest form of wireless encrytion and has two basic types of implementation. The first is fairly complex and is more of a corporate method utilising a "Radius Server" which is only available on Server operating systems, but WPA-PSK (Pre-shared key) is designed just for home & small office users who usually DIY, and it's a piece of cake. Much the same as WEP in that it uses a key to authenticate, WPA-PSK will automatically change its key every so often which makes it much harder for an eavesdropper to sniff enough info to attempt to put together the key.
WPA is almost identical to set up as WEP and involves specifying either
a keyword (to generate a key) or the key itself using the methods above
Note: WPA-PSK is a fairly recent upgrade to many products and you may need to download the latest firmware and Wireless Configuration Utilities from the manufacturer if you can't see the option. Windows XP's WZC utility has a WPA upgrade available through Windows Update.
WPA is one of the toughest forms of Wireless Security using encryption,
but it does have a fairly high overhead. Not so much affecting the throughput
(I usually get similar wireless speeds with WPA-PSK as I do with no security)
but more with how much processing power it takes to deal with. Cheaper
WAPs and Routers in theory may start to stall and stutter with as few
as 5-10 active Wireless PCs running WPA, but I'm yet to test this or hear
from anyone who has stressed a Router or WAP out with too many WPA protected
Hiding SSID is fairly limited as far as security goes. It will make your WAP "invisible" to a degree to your neighbours and other people who might innocently discover your wireless network and connect out of curiosity but it is quite easy to work around for someone with a moderate amount of knowledge using readily available tools such as Netstumbler or by using the rogue Access Point method. There's also evidence to suggest that hiding SSID might degrade network performance so all in all there's probably very little to be gained in hiding it.
VPN (Virtual Private Network) is usually used to network PCs together across the Internet where a variety of authentication measures are employed including encryption and username/passwords in order to secure the connection so that not just anyone can connect to a VPN server. These same authentication processes can be utilised to secure a Wireless Network, but you need a product to support this feature and they're usually fairly expensive (and complicated to set up).
Wireless Access Point.
A WAP is to wireless PCs what a switch is to cabled PCs. All it does
is provide a central point for the Wireless PCs to connect to, and allow
for Wireless Security methods like WEP or WPA to be controlled from.
A Wireless Router is a Router with a
WAP built into it, and I'm yet to see one that doesn't also have a built-in
4 port switch so they more or less combine the three devices in the image
above into one. Some also have built-in modems to provide even more cost
and space savings.
A Wireless bridge connects two points together wirelessly instead of using a cable. The bridge can be plugged either directly into a Network Card in a PC or into a hub or switch and it will function just the same.
The Bridge is generally configured via your Web Browser (the same as
a Router) or using a software tool that the manufacturer provides. Usually
they require specifying the Mac Address of the bridge
that they'll be connecting to and have security options like WEP
Bridge to Bridge (As shown in the image above)
Bridge to multi-point (Same as above just with several bridges connecting
Repeater (the 2nd bridge can function as a bridge [receiver] and Access
Point at the same time).
A Wireless Client is a variation of a Wireless Bridge except its job is to receive a wireless signal rather than broadcasting one like a WAP or straight bridge does. Many Wireless Bridges can also function in Wireless Client mode, but not all do so read the spec sheets carefully before you buy.
A Wireless Client receives from another source, and unlike straight
bridges, they're usually (but not always) compatible with other brands
and models of Wireless Products that can send a Wireless Broadcast.
A Wireless Media Player is a device that can find digital media from
networked PCs and then play them on a Home Entertainment System.
A Wireless PCI Card is fitted to the Motherboard of a Desktop
PC (so that the antenna sticks out of the back) and allows the PC to connect
to a Wireless Access Point or Wireless Router.
A Wireless PCMCIA Card goes into the PCMCIA (aka Card Bus) slot of a
Laptop PC and allows it to connect to a Wireless Access Point or
A Wireless USB Adapter goes into the USB port of a Laptop or Desktop
PC and allows it to connect to a Wireless Access Point or Wireless Router.
A Wireless Repeater function, also known as * WDS (Wireless Distribution System), Universal Repeater and Repeater Bridge, can receive a wireless signal (like a Wireless Client) and then rebroadcast it (like a WAP). This means they don't need to be cabled into the network. This can be a huge advantage but they do take a bit of skill to configure (read: right royal pain) and compatibility between different brands and models is a very common problem. The exception to this is products advertised with cross-brand compatibility such as most of Netgear's Universal Range Extenders. In all cases check the manufacturer's website for mention of cross-brand compatibility or a compatibility list. If the manufacturer doesn't mention it and doesn't have a list then assume it will only be compatible with another of the same model. If in doubt, get it confirmed in writing from the manufacturer before you purchase.
Note: I made it easy to find WAPs with repeater capability on my online shop by searching the word "repeater".
* To check out the differences between repeater modes like WDS, Repeater, Universal Repeater, Client Bridge etc, check out this table at DD-WRT.
Having a removable antenna allows for it to be easily upgraded to an antenna with different broadcast properties. eg To allow an outdoor antenna to be fitted or even just a higher gain antenna to extend the wireless range.
There are two basic types of antennas, Omnidirectional and Directional
antenna is a directional antenna in a metal grid pattern that looks like
a UHF TV antenna. Sometimes they're housed inside bazooka style casings
to improve the directional abilities.
There's a bit of science to antenna selection and it's certainly a specialised field when it comes to outdoor wireless, but for those only looking for minor improvements for an indoor wireless application there's some relatively cheap off the shelf antennas that can make quite a reasonable improvement.
Basically, most wireless routers and access points come with 2-2.5dbi antennas standard which are generally good for up to 100 metres outdoors with clear line of sight or up to 30 metres or so indoors through one or two walls or other obstacles (except solid objects such as tin or metal or concrete) . Upgrading to 5 dBi antennas will generally yield a 10 - 20% increase in range. This isn't a huge step up but it's usually enough to stabilise a choppy connection with a tendency to drop out. However, it's probably not going to help a PC that previously had no signal at all. eg I found that the position of my DSM-320 required the signal to have to get around (or through) two concrete pillars to get to the Wireless Router and it would occasionally drop the wireless link. After upgrading it to a 5dbi antenna it stayed totally stable.
Upgrading to 7 dbi antennas will generally yield a similar 10-20% increase in performance again over the 5 dbi.
The general rule of thumb is that in most 3 or 4 bedroom, low or high set brick veneer homes, a standard wireless product with a 2 or 2.5 dbi antenna will perform fine. Choose a 5 or 7 dbi option if you've previously had a wireless device that struggled to perform at your location or you're confident that a standard product is going to struggle at your premises because of its size, design or location.
Green is the standard 2.5dBi antenna
Tools like Benelec's EIRP calculator are invaluable for calculating antenna choices but it's still an area for the experts once it goes beyond slapping a higher dbi version of the same antenna onto an item. The equipment at this level isn't exactly cheap and the price varies considerably from one antenna to another, so a few dollars in the pocket of an experienced technician to consult on the job will generally save a lot of dollars and wasted time down the track.
Also bear in mind there are a variety of connectors that have both male and female ends so even choosing off the shelf cables can be tricky. The most common type of connector is SMA which you'll find on most Billion, Draytek, Netgear and D-Link wireless products. Another less common one is the TNC connector which can be found on some of the older Linksys products like the WRT54GL. And then you've got N type connectors which are often found on stand alone antennas and pre-made cables.
1. If using XP, check WZC utility is not interfering.
See also 5.7 below.
1. Check the manufacturer's minimum system requirements
to see if your PC and Operating System are compatible with the card.
This behaviour is common if WEP or WPA-PSK is enabled on the WAP but
an incorrect pass key is being used to try to connect to it.
1. The most common cause of this is if your wireless PC is right on the
edge of the WAP's range. See this
Billion forum post for simple ways to improve range.
This is a fairly rare one but will usually be for one of the following
Still looking into this one but it's been coming up a lot. I did find
some info on Google with some likely solutions -
The Wireless Network Tab is found under Control Panel > Network Properties
> Right-Click on Wireless LAN card and select Properties.
General Tech Articles
Wireless Community Groups
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