Wireless Networking

A wireless LAN (WLAN) is a flexible data communication system implemented as an extension to, or as an alternative for, a wired LAN within a building or campus.
Wireless network is a network set up by using radio signal frequency to communicate among computers and other network devices. It is also referred to as WiFi network or WLAN. This network is popular due to easy to setup feature and no cabling involved. Using electromagnetic waves, WLANs transmit and receive data over the air, minimizing the need for wired connections. Thus, WLANs combine data connectivity with user mobility, and, through simplified configuration, enable movable LANs.
One can connect computers anywhere in homes without the need for wires. Today WLANs are becoming more widely recognized as a general-purpose connectivity alternative for a broad range of business customers.
Let’s say there are two computers each equipped with wireless adapter and set up of wireless router. When the computer sends out the data, the binary data is encoded to radio frequency and transmitted via wireless router. The receiving computer then decodes the signal back to binary data.
It doesn’t matter whether the user is using broadband cable/DSL modem to access Internet, both ways work with wireless network. Wireless hotspot implies that the location is equipped with wireless devices for the user and others to join the network.
The two main components of wireless networking are wireless router or access point and wireless clients.
In the absence of any wired network, just get a wireless router and attach it to cable/DSL modem. Now you can set up wireless client by adding wireless card to each computer and form a simple wireless network. You can also cable connect computer directly to router if there are switch ports available.
If there is a wired Ethernet network at home, you can simply attach a wireless access point to existing network router and have wireless access at home.
The most important thing to be kept in mind is that the wireless router or access points should be installed in a way that maximizes coverage as well as throughput. The coverage provided is generally referred to as the coverage cell. Large areas require more than one access point in order to have adequate coverage. One can also add access point to an existing wireless router to improve coverage.
Types of Wireless: The major types of wireless these days include the following:
Wireless Local Area Networks (LANs)
802.11b (sometimes called wireless Ethernet)
802.11a, HiPerLAN II, and HomeRF (alternatives to 802.11b)
Fixed Broadband Wireless Multiservice Wide Area Networks (WANs)
MMDS and LMDS
Small Dish Satellite
Mobile Wireless (voice/telephony with increasing integration of data and video)
Wireless Personal Area Networks
Based on Bluetooth™ technologies
Wireless Operating Mode
The IEEE 802.11 standards specify two operating modes: infrastructure mode and ad hoc mode.
Infrastructure mode is used to connect computers with wireless network adapters, also known as wireless clients, to an existing wired network with the help from wireless router or access point.
Ad hoc mode is used to connect wireless clients directly together, without the need for a wireless router or access point. An ad hoc network consists of up to 9 wireless clients, which send their data directly to each other.
Wireless LANs frequently augment rather than replace wired LAN networks-often providing the final few meters of connectivity between a backbone network and the mobile user. The following list describes some of the many applications made possible through the power and flexibility of wireless LANs:
Doctors and nurses in hospitals are more productive because hand-held or notebook computers with wireless LAN capability deliver patient information instantly.
Consulting or accounting audit engagement teams or small workgroups increase productivity with quick network setup.
Network managers in dynamic environments minimize the overhead of moves, adds, and changes with wireless LANs, thereby reducing the cost of LAN ownership.
Training sites at corporations and students at universities use wireless connectivity to facilitate access to information, information exchanges, and learning.
Network managers installing networked computers in older buildings find that wireless LANs are a cost-effective network infrastructure solution.
Retail storeowners use wireless networks to simply frequent network reconfiguration.
Trade show and branch office workers minimize setup requirements by installing reconfigured wireless LANs needing no local MIS support.
Warehouse workers use wireless LANs to exchange information with central databases and increase their productivity.
Network managers implement wireless LANs to provide backup for mission-critical applications running on wired networks.
Senior executives in conference rooms make quicker decisions because they have real-time information at their fingertips.
Thus we can see that in any corporate enterprise, wireless LANs are implemented as the final link between the existing wired network and a group of client computers, giving these users wireless access to the full resources and services of the corporate network across a building or campus setting.
The widespread acceptance of WLANs depends on industry standardization to ensure product compatibility and reliability among the various manufacturers. The major motivation and benefit from Wireless LANs is increased mobility. Untethered from conventional network connections, network users can move about almost without restriction and access LANs from nearly anywhere.
The other advantages for WLAN include cost-effective network setup for hard-to-wire locations such as older buildings and solid-wall structures and reduced cost of ownership-particularly in dynamic environments requiring frequent modifications, thanks to minimal wiring and installation costs per device and user. WLANs liberate users from dependence on hard-wired access to the network backbone, giving them anytime, anywhere network access.
The most critical issue affecting WLAN demand has been limited throughput.
The data rates supported by the original 802.11 standards are too slow to support most general business requirements and slowed the adoption of WLANs.
Recognizing the critical need to support higher data-transmission rates, the IEEE ratified the 802.11b standard (also known as 802.11 High Rate) for transmissions of up to 11 Mbps. After 802.11b one more standard 802.11a has been ratified and in January 2002 the draft specification of another 802.11g has been approved. 802.11g is expected to be ratified till early 2003.
Competing Technologies to IEEE 802.11
HiperLAN2
HiperLAN2 is a wireless LAN technology operating in the license free 5 GHz (5.4 to 5.7 GHz) U-NII band. Under development by the European Telecommunications Standardization Institute (ETSI) Broadband Radio Access Networks (BRAN) project, HiperLAN2 is designed to carry ATM cells, IP packets, firewire packets, and digital data from cellular phones. Whereas 802.11a is a form of wireless Ethernet, HiperLAN2 is commonly regarded as wireless ATM.
An extension the 802.11 standard, 802.11a is connectionless Ethernet-like standard, meaning there isn’t a persistent connection between client and server. On the other hand, HiperLAN2 is based on connection-oriented links, though it can accept Ethernet frames. 802.11a is optimized for data communications, as are all standards based on 802.11.
HiperLAN2 is best suited to wireless multimedia because of its integrated Quality of Service (QoS) support. HiperLAN2 will have a difficult time competing with the momentum of 802.11a for several reasons. 802.11a has year head start over HiperLAN2. In addition, the 802.11a group looking for ways to incorporate the best features of HiperLAN2 within its own standards. It is expected that one merged European standard will emerge and it will most likely be 802.11a incorporating the best features of HiperLAN2.
HomeRF
HomeRF was the first practical wireless home networking technology and came out in mid-2000. HomeRF stands for Home Radio Frequency, as it uses radio frequencies to transmit data over ranges of 75 to 125 feet.
HomeRF uses SWAP (Shared Wireless Access Protocol), which is a hybrid standard, developed from IEEE 802.11. SWAP can connect up to 127 network devices and transmits at speeds up to 2Mbps.
Overall the major disadvantage to a HomeRF network is data transmission speed. Two Mbps is fine for sharing files and printing normal files. It is insufficient for streaming media and printing or transferring large graphic files. HomeRF still provides some advantages to those wanting a less expensive wired network solution. HomeRF also does not interfere with Bluetooth and is better for transmitting voice signals.