IEEE 802.11 is a set of media access control (MAC) and physical layer specifications for implementing wireless local area network (WLAN) computer communication. The first version was created in 1997 by the Institute of Electrical and Electronics Engineers (IEEE)
This article will explain some of the details of the 802.11a, 802.11b, 802.11g, 802.11n and 802.11ac wireless standards. These are collectively referred to as Wi-Fi Technologies.
802.11: The very first WLAN standard created by the IEEE in 1997, also known as 802.11 – 1997 or 802.11 (Legacy Mode). Was very slow even for the time it was built, only supporting a maximum network bandwidth of 2Mbps. For this reason, ordinary 802.11 wireless products are no longer manufactured.
802.11b: Released in 1999, 802.11b was the first Wi-Fi wireless network communication technology to gain mass adoption with consumers. 802.11b boosted the networking speeds of the original 802.11 standard from 2Mbps to 11Mbps and helped launch the first wave of wireless home networking with manufacturers of broadband routers beginning to sell Wi-Fi routers alongside the Ethernet routers they had been selling before. 802.11b has the lowest cost of the Wi-Fi standards but as a result it also has the slowest maximum speed.
802.11a: 802.11a was developed in 1999 at the same time as 802.11b. While 802.11a was much faster than 802.11b – having support for a bandwidth of up to 54Mbps – it failed to catch on with the home market as well as the 802.11b standard due to the higher costs involved. Because of these costs the 802.11a standard would typically be found on business networks.
802.11g: 802.11g was developed in 2003 and combines the qualities of both 802.11a and 802.11b. It supports bandwidth up to 54Mbps just like 802.11a and operates on the same 2.4GHz frequency as 802.11b. 802.11g hardware is fully backwards compatible with 802.11b hardware. In an 802.11g network, however, the presence of a legacy 802.11b participant will significantly reduce the speed of the overall 802.11g network. Due to the increased speeds, 802.11g comes with a higher cost than 802.11b and certain devices, such as wireless keyboards can cause interference with the signal.
802.11n: 802.11n was developed in 2009 and designed to replace the older 802.11a, 802.11b and 802.11g Wi-Fi technologies. It improves on 802.11g in the amount of bandwidth supported by using Multiple Input Multiple Output antennas on its networking devices; these are often referred to as MIMO devices. 802.11n can operate on both the 2.4GHz and 5GHz frequency bands and can provide a theoretical maximum bandwidth of up to 600Mbps. It is also more resistant to interference from outside sources but its use of multiple signals can interfere with nearby networks based on 802.11b or 802.11g.
802.11ac: 802.11ac is a standard for Wi-Fi wireless networking more advanced than the previous generation 802.11n standard. Developed in 2014, 802.11ac offers better network performance and capability implemented through more advanced hardware and device firmware compared to its predecessors. 802.11ac offers backward compatibility to 802.11b/g/n and operates on both the 2.4GHz and 5GHz frequency bands, offering bandwidth rated up to 1300 Mbps on the 5 GHz band and up to 450 Mbps on 2.4 GHz. It does this by using a larger number of MIMO radios and antennas to enable more simultaneous transmissions.
As well as the wireless standards discussed above, there are also versions of the 802.11 standard that are designed to support the creation of technologies for wireless local area networking.
• 802.11c - operation of bridge connections
• 802.11d - worldwide compliance with regulations for use of wireless signal spectrum
• 802.11e - Quality of Service (QoS) support
• 802.11F - Inter-Access Point Protocol recommendation for communication between access points to support roaming clients
• 802.11h - enhanced version of 802.11a to support European regulatory requirements
• 802.11i - security improvements for the 802.11 family
• 802.11j - enhancements to 5 GHz signaling to support Japan regulatory requirements
• 802.11k - WLAN system management
• 802.11m - maintenance of 802.11 family documentation
• 802.11p - Wireless Access for the Vehicular Environment
• 802.11r - fast roaming support via Basic Service Set transitions
• 802.11s - ESS mesh networking for access points
• 802.11T - Wireless Performance Prediction - recommendation for testing standards and metrics
• 802.11u - internetworking with 3G / cellular and other forms of external networks
• 802.11v - wireless network management / device configuration
• 802.11w - Protected Management Frames security enhancement
• 802.11y - Contention Based Protocol for interference avoidance
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