WiFi. What is it?
Following are a few facts
Back in 1991 Wi-Fi was invented by
the Netherlands. Initially meant for cashier systems the first wireless
products were brought on the market under the name WaveLAN with speeds of
1Mbps/2Mbps. Vic Hayes who is the inventor
of Wi-Fi has been named 'father of Wi-Fi' and was with his team involved in
designing standards such as
802.11b, 802.11a and 802.11g. In 2003, Vic retired from Agere Systems. Agere
Systems suffered from strong competition in the market even though their
products were cutting edge, as many opted for cheaper Wi-Fi solutions.
Agere's 802.11abg all-in-one chipset (code named: WARP) never hit the
market, Agere Systems decided to quit the Wi-Fi market in late 2004.
Wi-Fi: How it works
The typical Wi-Fi setup contains one or more
Access Points (APs) and one or more clients. An AP broadcasts its
(Service Set Identifier, Network name) via packets that are called
which are broadcasted every 100ms. The beacons are transmitted at 1Mbps, and
are relatively short and therefore are not of influence on performance.
Since 1Mbps is the lowest rate of Wi-Fi it assures that the client who
receives the beacon can communicate at at least 1Mbps. Based on the settings
(i.e. the SSID), the client may decide whether to connect to an AP. Also the
running on the client Wi-Fi card is of influence. Say two AP's of the same
SSID are in range of the client, the firmware may decide based on signal
ratio) to which of the two AP's it will connect. The Wi-Fi
standard leaves connection criteria and roaming totally open to the client.
This is a strength of Wi-Fi, but also means that one wireless adapter may
perform substantially better than the other. Since Windows XP there is a
feature called zero configuration which makes the user show any
network available and let the end user connect to it on the fly. In the
future wireless cards will be more and more controlled by the operating
system. Microsoft's newest feature called SoftMAC will take over from
on-board firmware. Having said this, roaming criteria will be totally
controlled by the operating system. Wi-Fi transmits in the air, it has the
same properties as a non-switched ethernet network. Even collisions can
therefore appear like in non-switched ethernet LAN's.
Wi-Fi vs. cellular
Some argue that Wi-Fi and related consumer
technologies hold the key to replacing
networks such as
obstacles to this happening in the near future are missing
the narrowness of the
and the limited range of Wi-Fi. It is more likely that
could compete with other cellular phone protocols such as
However, Wi-Fi is ideal for
applications like in a corporate LAN or SOHO environment. Early adopters
were already available in the late '90s, though not until 2005 did the
market explode. Companies such as Zyxell,
and many more are offering VoIP Wi-Fi phones for reasonable prices.
In 2005 ADSL ISP providers started to offer
services to their customers (eg. the dutch ISP
Since calling via VoIP is low-cost and more often being free, VoIP enabled
ISPs have the potential to open up the VoIP market. GSM phones with
integrated Wi-Fi & VoIP capabilities are being introduced into the market
and have the potential to replace land line telephone services.
it seems unlikely that Wi-Fi will directly compete against cellular.
Wi-Fi-only phones have a very limited range, and so setting up a covering
network would be too expensive. Therefore these kinds of phones may be best
reserved for local use such as corporate networks. However, devices capable
of multiple standards may well compete in the market.
Advantages of Wi-Fi
systems, Wi-Fi uses unlicensed radio spectrum and does not require
regulatory approval for individual deployers.
Allows LANs to be
deployed without cabling, potentially reducing the costs of network
deployment and expansion. Spaces where cables cannot be run, such as
and historical buildings, can host wireless LANs.
Wi-Fi products are
widely available in the market. Different brands of access points and
client network interfaces are interoperable at a basic level of service.
vendors has lowered prices considerably since their inception.
Wi-Fi networks support
roaming, in which a mobile client station such as a laptop computer
move from one access point to another as the user moves around a
building or area.
Many access points and
network interfaces support various degrees of encryption to protect
traffic from interception.
Wi-Fi is a global set
of standards. Unlike cellular carriers, the same Wi-Fi client works
different countries around the world.