Friday, February 3, 2017

Certified Wireless Network Administrator (CWNA) and History of WLAN

I recently took the CWNA exam and got my PDF cert the next business day, which I downloaded from CWNP's portal. This is my first IT cert for 2017 and I'm now preparing for my Palo Alto ACE (hopefully to get PCNSE afterwards). The same procedure to schedule for an exam and obtaining the CWNA cert can be found on my previous blog post when I took the CWTS last year.


History of WLAN

In the 19th century, numerous inventors and scientists, including Michael Faraday, James Clerk Maxwell, Heinrich Rudolf Hertz, Nikola Tesla, David Edward Hughes, Thomas Edison, and Guglielmo Marconi, began to experiment with wireless communications. These innovators discovered and created many theories about the concepts of electrical magnetic radio frequency (RF).

Wireless networking technology was first used by the US military during World War II to transmit data over an RF medium using unclassified encryption technology to send battle plans across enemy lines. The spread spectrum radio technologies often used in today's WLANs were also originally patented during the era of World War II, although they were not implemented until almost two decades later.

In 1970, the University of Hawaii developed the first wireless network, called ALOHAnet, to wirelessly communicate data between the Hawaiian Islands. The network used a LAN communication Open Systems Interconnection (OSI) layer 2 protocol called ALOHA on a wireless shared medium in the 400 MHz frequency range. The technology used in ALOHAnet is often credited as a building block for the Medium Access Control (MAC) technologies of Carrier Sense Multiple Access with Collision Detection (CSMA/CD) used in Ethernet and Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) used in 802.11 radios.

In the 1990s, commercial networking vendors began to produce low-speed wireless dta networking products, most of which operated in the 900 MHz frequency band. The Institute of Electrical and Electronics Engineer (IEEE) began to discuss standardizing WLAN technologies in 1991. In 1997, the IEEE ratified the original 802.11 standard that is the foundation of the WLAN technologies that you will be learning about in this book.

This legacy 802.11 technology was deployed between 1997 and 1999 mostly in warehousing and manufacturing environments for the use of low-speed data collection with wireless barcode scanners. In 1999, the IEEE defined higher data speeds with the 802.11b amendment. The introduction of data rates as high as 11 Mbps, along with price decreases, ignited the sales of wireless home networking routers in the small office, home office (SOHO) marketplace. Home users soon became accustomed to wireless networking capabilities in the workplace. After initial resistance to 802.11 technology, small companies, medium-sized businesses, and corporations began to realize the value of deploying 802.11 wireless networking in their enterprises.

If you ask the average user about their 802.11 wireless network, they may give you a strange look. The name that people often recognize for the technology is Wi-Fi. Wi-Fi is a marketing term, recognized worldwide by millions of people as referring to 802.11 wireless networking.

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