WiFi

=WiFi=

Arthur : Steve Hong Wi-Fi stands for Wireless Fidelity. It is a trademark owned by the trade group Wi-Fi Alliance (WFA). **[#1]** The Wi-Fi Alliance is a global and non-profit organization of companies (3Com, Cisco (previously Aironet), Intersil (previously Harris Semiconductor), Agere (previously Lucent), Motorola (previously Symbol Technologies), Sony, Apple and Panasonic. **[#2]** It uses Wireless Local Area Network (WLAN) to connect devices (using IEEE 802.11 technology) to the internet. (IEEE-Institute of Electrical and Electronic Engineers) **[#2]** Wi-Fi uses radio technology (802.11) to allow connections which the radio bands ranges from 2.4 or 5 GHz. **[#3]** 2.4 and 5 GHz signals are license free meaning they allow devices to connect to Wi-Fi without the need of government license. **[#3]** Wi-Fi Alliance certifies certain products which properly provide connection to devices and their signals aren't interfered with other devices using signals. **[#3]** Wi-Fi allows connection to the internet without having to find a wired network in places such as coffee shops, airports, campuses, offices, etc. **[#3]** Wi-Fi can be provided to multiple users at the same time (using Wi-Fi routers/modems) in the same place and also enables users to share files, printers, internet access, etc. **[#3]** This IEEE 802.11 technology is common in today's smartphones, labtops, video game consoles, printers or other devices. **[#1]** For example Iphone, Ipad, smartphones of Nokia, HTC and almost any labtops can use Wi-Fi. **[Source : Myself]** Installation of Wi-Fi is extending these days to the whole city or campuses of universities. Therefore anywhere you go whether indoor/outdoors in the city or campus, you can stay connected to the internet. **[#1]** Because Wi-Fi chipset prices are decreasing, it has become a common and convenient way to connect to the internet. **[#1]** To this popularity many operating systems and application markets are developing based on web-surfing, web contents and applications. (Iphone OS, Android platform, etc) **[Source : Myself]**

However there are some drawbacks to Wi-Fi. First, it has limitation in distance therefore, it is hard to use Wi-Fi in a big place (although it is possible by using routers with long range signals but is expensive). [**#1]** Another drawback of Wi-Fi is its security problems. One of Wi-Fi's advantage was that multiple users can connect to a network at the same time, but this is also a disadvantage. Because Wi-Fi connects to a public network, others can easily see DNS requests and information that is being tranferred to your devices. In other words, they can see what websites you are visiting or use information from your computer (such as cookie files) to log onto websites with your ID and password. Because of the security dangers, certain sites use HTTP encryption and other ways to protect the users' information. Still, it would be better to avoid doing internet banking or something which others may steal information from. [**Source #1, Mr. Aleman]**
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There are four types of 802.11 Wi-Fi technologies. They differ in performance, frequency and bandwidth. However the new Wi-Fi technologies are also made sure that they work well in previous technologies (in Wi-Fi Certified Products) unless their frequency is different. 802.11n is currently the most newest technology released in October of 2009. **[#3]** 2.4 or 5 GHz (selectable), or 2.4 and 5 GHz (concurrent) || 450 Mbps ||
 * Wi-Fi Generations**
 * **Wi-Fi Technology** || **Frequency Band** || **Bandwidth or maximum data rate** ||
 * **802.11a** || 5 GHz || 54 Mbps ||
 * **802.11b** || 2.4 GHz || 11 Mbps ||
 * **802.11g** || 2.4 GHz || 54 Mbps ||
 * **802.11n** || 2.4 GHz, 5 GHz,
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**References :**
[] [Reference #1] [] [Reference #2] [] [Reference #3]

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