A Quick Guide to Wi-Fi Standards
By Steven Fletcher
With so many Wi-Fi standards... 801.22a, 802.11b, 802.11g, pre-N, 802.11i, MIMO, and more it’s easy to get confused as to which Wi-Fi gear is best for you. I’ll give you a quick rundown on what the major standards are, and what you need to know about them.
802.11 is the architecture for a series of Wi-Fi standards, all with letters following 802.11 (a, b, etc.). This family of standards was introduced in 1997 by the Institute of Electrical and Electronics Engineers, Inc. (IEEE), the standards body for all things Wi-Fi, but wasn’t approved until 1999. The 802.11 standards provides protocols to connect computers and other devices wirelessly to a network.
802.11a was the first of the IEEE standards for wireless LAN. Like the underlying 802.11 architecture, 802.11a was introduced in 1997 and approved in 1999. There were products (wireless access points, routers and cards) built for this standard, but they never had wide acceptance. 802.11a operates in the 5 Ghz band, which doesn't penetrate through objects very easily. Therefore, signal range was limited.
802.11b was the first wireless standard to receive wide adoption. Operating at 2.4 Mhz, signals with this standard didn't have the limited range problems of the 802.11a standard. But it’s maximum speed of 11 Mbps was slow for anyone used to wired networks.
Adoption started picking up, as low cost wireless hardware became available in the late 1990s and early 2000. Some older 802.11.bequipment is still being used though slow speed and signal interference from other 802.11b users can be a problem with in a small space.
Most 802.11b equipment has been or is being replaced with 802.11g equipment but it is still viable in situations where speed isn't critical.
802.11g being significantly faster than the older 802.11b standard, equipment using this standard is used today. First launched in 2003, it was quickly adopted because it offered a speed of 54 Mbps.
Due to the widespread use of 802.11 b LANs, access points and Wi-Fi cards at the time, manufacturers of the equipment meeting the new 802.11g standard also ensured their products were backwards compatible to the older ‘b’ standard.
Pre-N is the current state-of-the-art. It's called pre-N because manufactures are making equipment prior to the adoption of the 802.11n standard, by the IEEE. While pre-N equipment is designed for the "expected" standard there is no guarantee that it will in fact be compatible with the standard. One of the unsettled issues is backward compatibility with ‘b’ and ‘g’ equipment. There are several non-compatible submissions being considered for 802.11n.
802.11i s an amendment to the 802.11 standard specifying security mechanisms for Wi-Fi networks Advanced Encryption Standard (AES)
The draft standard was ratified on 24 June 2004, and supersedes the previous security specification, Wired Equivalent Privacy (WEP), which was shown to have severe security weaknesses. Wi-Fi Protected Access (WPA) had previously been introduced by the Wi-Fi Alliance as an intermediate solution to WEP insecurities. WPA implemented a subset of 802.11i. The Wi-Fi Alliance refers to their approved, interoperable implementation of the full 802.11i as WPA2 .
MIMO (pronounced MY-moh) stands for Multiple-input multiple-output. This enables Wi-Fi devices to use multiple channels, enabling faster speeds, much like dual chipsets in a computer. As used by the expected 802.11n standard, MIMO will offer up to eight times the coverage, and up to six times the speed, of current 802.11g networks.
802.16 Like 802.11n, this standard has yet to be finalized. It's the standard WiMAX and competing technologies will use to provide urban-wide wireless coverage. Right now the different wide area network technologies don't work with one another. Once 802.16 is approved, they should. But that probably won't happen for a couple of years.
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