Wireless Fidelity Networks

Advatange & Disadvantage of WiFi

Advantages of Wi-Fi

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Wi-Fiallows LANs to be deployed without cabling for client devices,typically reducing the costs of network deployment and expansion.Spaces where cables cannot be run, such as outdoor areas and historicalbuildings, can host wireless LANs.

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Wireless Fidelity (WiFi)Resource

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Asof 2007 wireless network adapters are built into most modernlaptops. Getting a laptop without a built-in WiFi has now become anexception. Wi-Fi chipset pricing continues to come down, making Wi-Fi avery economical networking option and driving inclusion of Wi-Fi in anever-widening array of devices. Wi-Fi products are widely available inthe market. Additionally, it has become quite ubiquitous in corporateinfrastructures thus helping with the deployment of RFIDtechnology that can piggyback on the Wi-Fi system already in place [4].

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Differentcompetitive brands of access points and client networkinterfaces are inter-operable at a basic level of service. Productsdesignated as "Wi-Fi Certified" by the Wi-Fi Alliance are backwardsinter-operable. Wi-Fi is a global set of standards. Unlike cellularcarriers, the same Wi-Fi client works in different countries around theworld.

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Widelyavailable in more than 250,000 public hot spots and tens ofmillions of homes and corporate and university campuses worldwide, asof 2007, Wi-Fi has become the preferred method of network connectivity.[citation needed]WPA is not easilycracked if strong passwords are used and WPA2encryption has no known weaknesses. New protocols for Quality ofService (WMM)and power saving mechanisms (WMM Power Save) make Wi-Fi even moresuitable for latency-sensitive applications (such as voice and video)and smallform-factor.

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Disadvantagesof Wi-Fi

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Spectrumassignments and operational limitations are not consistentworldwide. Most of Europe allows for an additional 2 channels beyondthose permitted in the US (1-13 vs 1-11); Japan has one more on top ofthat (1-14), and some countries, like Spain, prohibit use of thelower-numbered channels. Europe, as of 2007, is now essentiallyhomogeneous in this respect. Some countries, such as Italy, formerlyrequired a 'general authorization' for any Wi-Fi used outside anoperator's own premises, or require something akin to an operatorregistration.[citation needed]

href="http://en.wikipedia.org/wiki/Equivalent_isotropically_radiated_power" title="Equivalent isotropically radiated power">Equivalentisotropically radiated power (EIRP) in the EU is limited to20 dBm(0.1 W).

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Powerconsumption is fairly high compared to some other low-bandwidthstandards, such as Zigbee and Bluetooth,making battery life a concern.

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Themost common wireless encryption standard, Wired Equivalent Privacyor WEP, has been shown to be easily breakable even when correctlyconfigured. Wi-Fi Protected Access(WPA and WPA2), which began shipping in 2003, aims to solve thisproblem and is now available on most products. Wi-Fi Access Points typicallydefault to an open (encryption-free)mode. Novice users benefit from a zero-configuration device that worksout of the box, but without security enabled, providing open wirelessaccess to their LAN. To turn security on requires the user to configurethe device, usually via a software graphical user interface(GUI). Wi-Fi networks that are open (unencrypted) can be monitored andused to read and copy data (including personal information) transmittedover the network, unless another security method is used to secure thedata, such as a VPN or a secure web page. (HTTPS/SecureSocket Layer)

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Many2.4 GHz 802.11b and 802.11gAccess points default to the same channel on initial startup,contributing to congestion on certain channels. To change the channelof operation for an access point requires the user to configure thedevice.

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Wi-Finetworks have limited range. A typical Wi-Fi home router using 802.11b or 802.11gwith a stock antenna might have a range of 45 m (150 ft) indoors and 90m (300 ft) outdoors. Range also varies with frequency band. Wi-Fi inthe 2.4 GHz frequency block has slightly better range than Wi-Fi in the5 GHz frequency block. Outdoor range with improved antennas can beseveral kilometres or more with line-of-sight.

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Wi-Fipollution, or an excessive number of access points in thearea, especially on the same or neighboring channel, can prevent accessand interfere with the use of other access points by others, caused byoverlapping channels in the 802.11g/b spectrum, as well as withdecreased signal-to-noise ratio(SNR) between access points. This can be a problem in high-densityareas, such as large apartment complexes or office buildings with manyWi-Fi access points. Additionally, other devices use the 2.4 GHz band:microwave ovens, cordless phones, baby monitors, security cameras, andBluetooth devices can cause significant additional interference.

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Itis also an issue when municipalities[5],or other large entities such as universities, seek to provide largearea coverage. Everyone is considered equal for the base standardwithout 802.11e/WMM when they use the band. This openness is alsoimportant to the success and widespread use of 2.4 GHz Wi-Fi, but makesit unsuitable for "must-have" public service functions or wherereliability is required. Users sometimes suffer network "frustrations"or a total network breakdown if gaming because a neighbour microwavessome popcorn.

style="margin-left: 40px; font-family: Verdana; text-align: justify;">Interoperabilityissues between brands or proprietary deviationsfrom the standard can disrupt connections or lower throughput speeds onother user's devices that are within range. Additionally, Wi-Fi devicesdo not, as of 2007, pick channels to avoid interference.[citation needed]

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style="margin-left: 40px; font-family: Verdana; text-align: justify;">Courtesy of Wikipedia. Alltext is available under the terms of the GNUFree Documentation License. (See Copyrights for details.)