WiFi. What is it?

WiFi.  What is it?

Following are a few facts about WiFi:

History

Back in 1991 Wi-Fi was invented by NCR Corporation/AT&T (later on Lucent & Agere Systems) in Nieuwegein, 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 IEEE 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 SSID (Service Set Identifier, Network name) via packets that are called beacons, 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 firmware 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 strength (Signal-to-noise 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 cellular telephone networks such as GSM. Some obstacles to this happening in the near future are missing roaming and authentication features (see 802.1x, SIM cards and RADIUS), the narrowness of the available spectrum and the limited range of Wi-Fi. It is more likely that WiMax could compete with other cellular phone protocols such as GSM, UMTS or CDMA. However, Wi-Fi is ideal for VoIP 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, UT Starcomm, Samsung, Hitachi and many more are offering VoIP Wi-Fi phones for reasonable prices.

In 2005 ADSL ISP providers started to offer VoIP services to their customers (eg. the dutch ISP XS4All). 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.

Currently 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

• Unlike packet radio 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 outdoor areas
  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.
• Competition amongst vendors has lowered prices considerably since their inception.
• Wi-Fi networks support roaming, in which a mobile client station such as a laptop computer
  can 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
  in different countries around the world.