Wi-Fi

Testing Cisco's enterprise-class 802.11n access point

I’m just excited to learn that someone has finally evaluated an enterprise-class 802.11n access point. Until now all of the evaluations I’ve seen dealt with consumer-grade equipment. That kind of testing is important, but I personally would rather see what the big players are coming up with because enterprise-class devices are usually more like the real deal.

I hope the title is not too misleading as I didn’t run the tests personally. I’m just excited to learn that someone has finally evaluated an enterprise-class 802.11n access point. The InformationWeek article “First Look: Cisco’s 11n AP” presents a high-level view of the testing done by Syracuse University Real-World Labs. Until this article, all of the evaluations I’ve seen dealt with consumer-grade equipment. That kind of testing is important, but consumer equipment is more prone to be using proprietary firmware and or hardware. I personally would rather see what the big players are coming up with because enterprise-class devices are usually more like the real deal. Especially when most enterprise 802.11n Draft 2.0 equipment developers are ensuring that their products will be upgradeable to the final 802.11n specifications.

Hopeful progress as seen by the article

The industry is betting on a smoother rollout of 802.11n equipment, mainly because of the key role Wi-Fi Alliance has played in certifying pre-release 802.11n equipment. Remember that the 802.11g protocol was finalized before the Wi-Fi Alliance got involved.

The 5 GHz frequency range is going to see much more use for a multitude of reasons. Over-crowding of the 2.4 GHZ frequency band and lack of non-interfering channels are two well known reasons. One less obvious reason is that 802.11n offers increased coverage in both the 2.4 GHz and 5 GHz frequency bands. This will allow an 802.11n device using the 5 GHz frequency band to nearly mimic the RF propagation characteristics displayed by an 802.11b/g device using the 2.4 GHz frequency band.

MIMO and improved receiver intelligence will allow the use of RF multipath reflections to improve signal quality and eliminate the problem of null points. Awhile ago, I did a series on this subject culminating in the post, "802.11n, MIMO and multipath environments," where I talk about all the quirks of multipath environments including null points and how MIMO will effectively eliminate them.

Evaluation results

The InformationWeek article for the most part validates what everyone has been expecting and hoping for. The 802.11n access point outperforms the 802.11a/g access point in almost every category. The one area where the 802.11n access point does not show any significant improvement is range. This surprises many people; they automatically associate improved coverage with greater range. It’s just not that clear cut. RF propagation is basically an expanding wave front and range is simply a function of power level when all other variables are identical. So any serious improvement in range shouldn’t be expected as both protocols use the same RF output power specifications.

The article’s timely information, in my opinion, is great news and reaffirms the results I’ve seen during my modest evaluation of other 802.11n equipment. I also consider the article noteworthy because the actual testing uses the 802.11a/g based Cisco 1240 as a baseline, showcasing the improvements seen when using the 802.11n based Cisco 1250.

All in all, I’m beginning to get a sense that the 802.11n protocol is the precursor to a major technological shift ultimately eliminating wired user networks.

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2 comments
Michael Kassner
Michael Kassner

The article reflected my own testing and evaluation. Have you seen similar results? Does this evaluation change your mind about waiting until the 802.11n protocol is ratified?

seanferd
seanferd

For any of the cheaper consumer-grade routers, however, I would probably wait 6 months to a year after the protocol is ratified to buy an n version wireless router. In my understanding, consumer products claiming to be ready for up-and-coming protocols have been iffy in the way of actually functioning per the specification with other wireless cards and equipment. I would think that Cisco has the bases covered (perhaps not with the Linksys brand). You pay a premium on their products for a reason.