What is WiFi
WiFi is a technology that allows data transfer over specified
radio frequencies, this in turn removes the need for cabled
connections making device portability possible. The WiFi
revolution has been trumpeted on a number of occasions but has
stalled each time on security fears or cost, but as mobile hones
have driven the publics understanding of wireless communication
the consumer appetite for WiFi products has grown steadily to a
point where it became commercially viable.
How does it work
Moving data using radio frequency is nothing new, in fact the
first Morse code radio transmission has a lot in common with
today's wifi technology, after sending what is in effect the
first binary wireless transmission mankind spent the next 20
years perfecting the reproduction of the human voice in an
analogue format.
The telephone while revolutionary did mask the ability of
data transmission , this was not left to rot as militaries
around the world continued to develop the sending of data via RF
transmissions. WIFI of today is a distant cousin of that Morse
signal, although instead of a low bandwidth dot and dash being
sent thousands of bits of data are sent every second and we are
now measuring in kilobits per second and with newer technologies
even megabits.
Wifi as a standard uses the 2.4 Ghz range which is largely
unused by the European military and other RF users like mobile
communications, this frequency band is then broken down into
channels which a wireless device can use to transmit data and in
order to avoid interference the devices can frequency hop or
jump between them mid data stream.
So we have a method of moving data over RF but each device
needs to be connected and enabled to work with Wifi, this is in
effect like giving each device in your network a handheld radio
(except they work at much high frequencies). Over this radio
link the binary DataStream carries your data for example a
webpage back to the device that requested it. A laptop for
example would have a wireless access card or dongle this is both
a transmit and receive device, this could connect to another
laptop with the same setup and create a point to point
connection. It is far more likely that the laptop and any other
client device will connect to a router or access point to join a
much larger wireless network.
Performance of any wireless link is limited by the same
factors that effect your radio or TV signal, weather, distance,
power and walls or objects, again an example if you use an
indoor aerial for your TV your signal is weaker and therefore
the picture quality drops. With a wifi network if the signal
strength or quality drops the effective data rate is reduced as
more packets are re sent to counteract the errors, so it is
important to bear in mind the maximum achievable range of a wifi
enabled device may be at the minimum sustainable speed.
WiFi Variants
The accepted wifi standards are set by the Institute of Electrical and Electronics
Engineers or IEEE, 802.11b was the first to market and is the
slowest in terms of raw bandwidth but is also the cheapest to
produce equipment for, with speeds up to 11mbits this is the
format that is most prevalent in today's electronics
marketplace.
Then there is 802.11a which strangely
came second, this can handle up to 54mbits and runs in the 5 Ghz
band, this has until recently been the domain of the corporate
network as 802.11a equipment costs more to purchase and gives
greater range.
The most recent entry is 802.11g
which is back on the 2.4 Ghz band but can achieve the 54mbps of
802.11a and brings the benefits of the cost reduction in
technology, if you are buying networking equipment 802.11g is
the best option today as it is also backwards compatible with
802.11b although your connection will run at the speed of the
slowest technology used.
Security
So we intend to send data through the airwaves, well its not
long before someone raises the security card and its right they
should, data sent on computer networks is always private be it a
web surfing session or email. Use of the industry standard
triple DES encryption was deemed too slow for wireless networks
which had limited bandwidth to cope with encryption overheads.
So WEP the wireless encryption protocol emerged as the preferred
method of securing the wireless connections, the 128bit WEP
standard is not bombproof but would take a few months with a
high powered server to crack, this of course assumes you don't
change the key which of course you will!.
WiFi Uses
So that's how so the next logical question is why and perhaps
how to implement wireless networking?
In the Home
Home networking is not fun, that is reflected in the number
of homes that have cabled CAT5 networks today, few homeowners
want to run cabling under floors and have unsightly connection
boxes in each room that you might use a device. So wireless is a
real answer offering the ability for a broadband internet
connection to be shared between users in the home, perhaps mum
using the PC, dad on a laptop in the garden while the kids hook
up their playststaion upstairs. Its only a small step from
sharing your internet connection to a full network, sharing a
printer and even a music server with all your collection stored
as MP3's
This is the area that has seen the wifi explosion the home is
leading the take up of wireless equipment and coupled with the
rapid uptake of broadband wifi growth is assured for the next
few years.
For home networking it is important to understand the
components, each device will need a wireless card or dongle,
they in turn connect to the hub which can be one of 3
devices.
The Wireless Access point is simply a translation device that
sits connected to your main PC and allows any wireless device to
talk to it, this means that if that PC is off then so is
everyone's internet connection. Next a Wireless router, this is
similar to the access point but allows routing around the home
network so 2 laptops can network even if the main PC is off, but
again if the internet connection is through the main PC if its
off then so is you web connection.
By far the most popular choice is a wireless router / modem,
be careful to get the right modem either dial up, DSL or ADSL
these allow you to network all of your devices and as long as
the wireless hub is on any device can access the internet,
commonly these will have an inbuilt firewall and some cabled
connections.
In the Workplace
The workplace on the other hand is far more cautious, most
offices already have a perfectly good and fast (at least
100mbits) network in place, so what benefits are there for
wireless? In strict terms for desktop PC's there are few, but
more and more workers are issued with laptops as standard. Those
laptops will almost certainly have a wireless access card as
standard and the new centrino technology for Intel means every
laptop shipped has embedded wifi.
So of course it makes sense to use wifi, but security
conscious businesses are not happy with the level of encryption
offered by WEP alone and are layering extra security on top far
beyond rolling updates of keys, this makes networks a nightmare
to manage and thus restricts growth in this area.
We must also consider the number of devices in an office
network there could be hundreds of devices trying to share the
limited number of channels, then there are issues of where to
site access points to work most efficiently. Its not all doom
and gloom with good planning these can be overcome to fully
extract the business benefits of wireless networks but it takes
some guts to get started.
In Public
When is a hotspot not a hotspot? when no one knows about
it!
And there lies the dilemma, while there is a market for those
who wish public internet access on their mobile devices there
are rarely enough users concentrated in one location to make it
pay. Even when there are at airports or stations getting the
average user to understand how to connect and pay for the time
they will be using the service is a tough job.
A number of providers in the UK are already out there, BT
openzone, Costa Coffee and even McDonalds wifi with a big Mac,
but how many of us, even the technically savvy ones have
actually use the service?
So what about a nationwide service provider of WiFi, well
arguably that's what BT hope open zone will become, but many
more ambitious plans have been muted, broadband balloons lurking
in the lower atmosphere and more recently broadband wifi
lampposts in every street. Great ideas but hugely capital
intensive to get going and in this market you come directly head
to head with mobile operators who hope to sell 3G data services,
they already have the networks and the subscriber base so
perhaps its fair to say hotspots will stay just that "spots"
Next Steps for Wifi
While many industry pundits (of whom we do not claim to be
one) talk of hot spots and longer ranges it seems likely that
the next 12 months will bring wifi into new devices, first
mobile phones will have wifi alongside Bluetooth then add wifi
to MP3 players allowing them to stream. Longer term Wifi may
become the defacto standard for connecting household electronics
and automating your home, heard this before? well yes that was
Bluetooth.
What's different about wifi, well its cheap, commonly
available and understood and if you don't have it in your home
maybe you should, this is a consumer led growth you should be
part of it.
