10-Minute Guide To Wi-Fi Standards

There's 801.22a, 802.11b, 802.11g, pre-N, 802.11i, MIMO, and more. How can you sort out the mess of Wi-Fi standards? Here's the rundown on what the major standards are, and what you need to know about them, from Brian Hernacki, architect, Symantec Research Labs, Cupertino, Calif.,

802.11- This is the overlying architecture for a series of Wi-Fi standards, all with letters following 802.11 (a, b, etc.). This family of standards was first introduced in 1997, but the Institute of Electrical and Electronics Engineers, Inc. (IEEE), the standards body for all things Wi-Fi, didn't approve them until 1999. The 802.11 family of standards provides protocols designed for local area networks and the devices that support them and connect with them.

It's not that wireless networking was unworkable before the introduction of 802.11, according to Hernacki, but any connections before were designed for packets transmitted over a wide variety of radio signals. Due to the wide range of signals in use, wireless networking this way was too cumbersome and, therefore, never enjoyed wide adoption, Hernacki says.

802.11a This 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. This enabled commodity-type access points, from Linksys, Netgear, et al.

"It's kind of a footnote in wireless history now," Hernacki says. "It didn't receive much adoption because it operates in the 5 Ghz band, which doesn't penetrate through objects very easily. Therefore, there were problems with absorption of the signal throughout an office. There were products (wireless access points, routers and cards) built for this standard, but I've never seen any of them."The problem with signal absorption more than outweighed the maximum 54 Mbs speed, Hernacki adds. Some 802.11a products and networks may still exist in some remote areas of the country.

802.11b This was the first wireless standard to receive wide adoption. Operating at 2.4 Mhz, signals with this standard didn't have the absorption problems of the 802.11a standard, but the slow speed (11 Mbps under optimal conditions) also meant that anyone used to broadband in an office or home setting would see achingly slow speeds. Adoption started picking up, as wireless LANs, chips, etc., started becoming available in the late 1990s and early 2000. Some older equipment still uses 802.11b, though slow speed and signal interference from other 802.11b users can be a problem in locations where there are several users in a small space, according to Hernacki.

However, the average age of a laptop is less than three years, so much of the 802.11b equipment has been replaced, though the environment still exists in some many installations where speed isn't critical.

802.11g This is significantly faster than the older 802.11b standard, so this standard is the one found in most locations today. First launched in 2003, it was quickly welcomed by early adopters because it offered the speed (54 Mbps) that enabled better, faster connections, making Internet downloads much more practical than through the 802.11b standard. It's standard on most equipment today.

Due to the proliferation of existing 802.11 b LANs, access points and Wi-Fi cards, manufacturers of the equipment meeting the new standard also ensured their products were backwards compatible to the older standard. This meant not only that the products could be used interchangeably, but also that anyone or any company looking to upgrade could do so as necessary without concerns about a "forklift" upgrade. So the LAN could be upgraded immediately, then laptops as necessary.

Pre-N: This is the current state-of-the-art standard. It's called pre-n because it's an intermediate solution prior to the adoption of the 802.11n standard, which Hernacki expects to occur sometime in 2007. One of the unsettled issues is backward compatibility. Pre-N equipment enables speeds more than double that of 802.11g equipment, in the right environment.Under 802.11n, speeds would increase even more. Additionally, the pre-N devices promise wide reach than the 802.11g devices. While this helps make wireless LANs wider reaching, it also raises some security issues. If, by late 2006, ratification looks immanent, Hernacki expects electronics stores to be swamped with 802.11n equipment -- pre-N equipment is designed for the "expected" standard -- for the 2006 holiday shopping season.

802.11i This is the basic wireless security standard. While 802.11i provides some security, it's cryptographically weak, so most companies require additional security. However, many individuals, despite warnings in computer columns and consumer-oriented technology publications, use this if they use any security at all.

802.1x This is a higher-level security standard than 802.11i and, like it, underlies the other 802.11 standards. This provides high-level authentication and security on the wireless networks, as well as access control. However, there are still some unsettled issues with this standard, so the IEEE has yet to ratify it.

MIMO This enables Wi-Fi devices to use multiple channels, enabling faster speeds, much like dual chipsets in a computer.

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, according to Hernacki.0