March 23, 2006



Posted: 06.04

802.11x: What’s Next?

Your Wi-Fi experience is getting ready to change. Will you be able to stay up to speed?
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By V. Wade Contreras

Many of us have become accustomed to the benefits of using a wireless local area network (WLAN) to get our work done, whether on a campus at the office, in the comfort of our homes or even in a wireless hot spot at the airport. So accustomed, in fact, that reverting to the occasional dial-up connection can quickly turn many of us petulant with frustration. The good news is, the wireless experience is set to change significantly in the next couple years, and it should be for the better. The challenge will be to simply keep up.

Most WLANs currently run on the 802.11b protocol, also known as Wi-Fi (wireless fidelity). But there are a growing number of competing protocols and enhancements aimed at addressing security concerns, network speed and the high-bandwidth applications coming out of development. So read on to find out what the big brains in the wireless industry will be rolling out to boost your WLAN. It’s a bit of an alphabet soup, but put on your thinking cap for a few minutes and nobody will be able to stump you at the water cooler. At least, not for a few months.

802.11g: Kicking It Up a Notch
The 802.11b standard has a theoretical throughput of 11 megabits per second (Mbps), but figure in the “overhead” that comes with all protocols and typical real-world throughput is less than 6 Mbps at best. However, 802.11g and 802.11a (both already available) have kicked 802.11b up several notches. 802.11g uses the same wireless spectrum—2.4 gigahertz (GHz)—as 802.11b, but it cruises along at 54 Mbps (real-world around 20 Mbps). 802.11a also runs at 54 Mbps, but it uses the 5 GHz band.

The “g” variety has enjoyed greater popularity, as it is backward compatible with 802.11b. The “a” variant isn’t compatible with “b,” and it doesn’t handle long transmit distances or interfering objects, such as walls and furniture, as well. While 802.11a may experience less interference in certain situations due to its less-crowded 5 GHz spectrum, many industry observers believe that, of the currently available protocols, 802.11g offers the best mix of speed and compatibility.

The latest news in the 802.11g realm are speed enhancement technologies from companies like Broadcom , which makes “g” even more attractive. Broadcom’s Afterburner technology is being marketed as 125 High Speed and is currently found in Wi-Fi products from companies such as Linksys, Belkin and Buffalo. It boosts speed on an all-802.11g network to about 34 Mbps real-world throughput. “125 High Speed gives you a nice performance boost,” says David Cohen, senior product marketing manager at Broadcom. “It’s compatible with other ‘g’ devices on the network, and it’s a good neighbor—it doesn’t cause any interference.”

There are competing “g” enhancement products that claim 108 Mbps theoretical throughput, known by the names “Super G” (Netgear) or “Xtreme G” (D-Link) to name a couple. Broadcom contends that such “108” technologies can cause interference to neighboring networks. Manufacturers that employ 108 dispute the claim. One caveat with the latest “g” enhancement technologies is they work best when an entire network is running them. “If you have a network that’s all 125-high-speed mode, you’ll of course achieve the best speed,” says Cohen. “But if have a network with some nodes that are 125-high-speed and some standard ‘g’—you’ll still have a better performing network than if you had all regular ‘g’ nodes.”

802.11n: Greased Lightning
While 802.11g and -.11a are the current cutting edge, about one year down the road they might be considered Wi-Fi turtles—that is, if 802.11n delivers on its promise of 100 Mbps or faster. The standard is currently under development by the Institute of Electrical and Electronics Engineers (IEEE), and it has been put on a fast track for completion, in part because of recent speed enhancement technologies, such as enhanced 802.11g discussed above. The IEEE met in Vancouver, Canada, in January of this year, and 802.11n was a hot topic.

Though it’s still hard to know exactly how the new protocol will shake out, some basic parameters have been defined. For instance, the standards body has mandated at least 100 Mbps throughput and a baseline 802.11n specification that must include all existing 802.11 functions, allowing only for amendments to throughput capability. It must be backward compatible with existing standards, such as 802.11g and 802.11a, meaning -.11n will most likely operate in both the 2.5 and 5 GHz bands. And it must be able to interoperate with other enhancement technologies in progress, such as 802.11i. In addition, 802.11n will measure speed differently than previous 802.11 variants, resulting in a smaller gap between theoretical and real world data rates. Estimates call for ratification by the end of 2005.

There may be companies that jump the gun on the new protocol, as happened with 802.11g, so pre-standard “n” products may make their way to market even before 802.11n is ratified. Broadcom was rumored to have such pre-standard products in the works, but it has denied the reports. The problem with pre-standard products is they sometimes cause confusion, and possibly interoperability, once the true standard hits. “Pre-standard products create the potential for confusion and problems, but at the same time early adopters typically are aware of the pains of early adoption,” says Vance.

802.11i: A Long Road
Now that we’ve talked about the flashy speed upgrades to 802.11, let’s take a moment to consider the sober topic of security. The road to security in the WLAN domain has been a long, soap opera of a story that still isn’t finished. The history of 802.11 security is littered with acronyms describing security protocols all aimed at protecting wireless data, some of which have ultimately proved to be inadequate.

The newest player in the security realm, and the one you’ll be hearing the most about in the near future, is 802.11i, which is a standard being created by the IEEE in an effort to one-better the current standard, WPA (Wi-Fi Protected Access). The Wi-Fi Alliance industry group created WPA to fix myriad problems associated with the early WEP (Wired Equivalent Privacy) standard.

“WEP really only attacked security from an encryption standpoint,” explains Vance. “WPA approaches it from both an authentication standpoint, with 802.1x, and a better encryption protocol called TKIP [Temporal Key Integrity Protocol].” Vance says 802.11i will ratchet up security even higher by employing a stronger authentication scheme called AES (Advanced Encryption System).

The IEEE standards group is expected to complete development of the standard in 2005, and only time will tell if the new standard delivers on high expectations. One thing that could affect adoption of 802.11i is the cost to upgrade to the new technology. The AES encryption system may require hardware replacement for some networks to come up to spec. And AES is processor intensive, so some wireless clients (notebooks, PDAs) might need to be replaced for a network to reach compliance. For large network installations, replacing a bunch of hardware for an unproven new protocol may be a tough sell early on. In contrast, when WPA came along to fix WEP deficiencies, upgrading usually required only firmware or software updates.

802.11e: Get the Picture?
Like 802.11i, 802.11e is an enhancement protocol, meaning it’s not a true wireless backbone but rather will ride alongside whatever flavor of 802.11 you are running and make it better. The enhancement here is allowing WLANs to handle streaming audio and video, thus enabling high-bandwidth applications like video conferencing and voice over IP Wi-Fi telephones.
The 802.11e protocol implements Quality of Service (QoS) features, which are currently used on wired Ethernet networks to allow applications to prioritize wireless traffic. Here’s how it shakes out: Current 802.11 networks use what is called best effort service, in which all network packets are treated with equal priority. So Web traffic, which is less time-sensitive, might take bandwidth from someone trying to stream audio or video, leading to choppy video or audio dropouts. QoS regulates network traffic, giving priority to bandwidth-intensive signals. The end result is the streaming media user will get a healthy audio/video feed, while the impact for the Web surfer might be only a tiny slowdown in a page load.

“Users have a certain level of expectation in terms of their experience with next-generation applications like voice and video,” says Vance. “Therefore, choppy video or voice is really unacceptable. Ensuring that that kind of traffic is prioritized … is very important, especially since voice looks to be a killer app in the enterprise, and video looks to be a killer app for home use.”

Another feature of 802.11e is packet bursting, which will allow 802.11g to perform better in a mixed-client environment. (Currently, an 802.11g network will see a slowdown if even one wireless client is using legacy 802.11b technology on the network.)

Believe it or not, there are a few more 802.11 protocols, such as the wide-area standard 802.16, aka Wi-Max. It is designed for large coverage areas up to 30 miles, but don’t look for it any time soon. Some other protocols will be transparent to users. For instance, 802.11k creates a way for access points to pass specific radio frequency health and management data to higher-level management applications; 802.11f recommends practices for WLAN equipment makers so that all their 802.11 access points can interoperate; and 802.11d enables 802.11 hardware to work in countries where it can't today.

V. Wade Contreras is a freelance writer based in Los Angeles.
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