Gee, I've got five bars on my wireless adapter but can't get near the 300-Mbps data rate that the guy down the hall gets on our new 802.11n network. And I'm just a few feet away from an access point! I better open a trouble ticket, right? Whatdya mean the problem might be my device? This laptop is like almost brand new, and it's got an 11n adapter!
Ah, clients. What would our wireless networks be without them? Things can be quirky enough with power-save settings, local RF conditions, and general machine health and resources when it comes to wireless performance, but add to the mix the general confusion that the wireless client adapter industry has created, and you can hardly fault your users for not understanding (or even wanting to hear about) the nuances of different wireless adapters in a given network.
A shrinking number of environments are fortunate enough from the support perspective to be able to dictate what wireless devices will be used on the network, as well as how they are rigidly and uniformly configured. For the rest of us, we strive to build out standards-based, high-performing WLAN environments that will hopefully serve a diverse range of clients well. But guaranteeing equal performance (whether measured or perceived) across different client devices is difficult. Much of the frustration lies with device manufacturers.
This is one area that I find myself ripping on Apple fairly often. It can be maddening to see what every minor OS version update does to wireless performance across the Apple product line, and release notes tend to be sparse on specific changes. At the same time, I have to give it up for Apple, for its long-running inclusion of dual-band adapters in the Mac notebook line. Macs produced even before the 11n standard was ratified came with 11a/g adapters that were 11n-ready, with the new capabilities toggled on in software at the appropriate time. This has been huge in my environment, but more on that in a bit.
As for PC manufacturers, I’ll be blunt. I realize that a penny saved during manufacturing can equal a nickel profit at time of sale, but these guys are making life frequently miserable for wireless admins. Furthermore, I stand here today and call out PC and wireless client manufacturers for impeding the progress and greater good of the wireless world at large. The sin? Turning out machines with 2.4 GHz-only adapters when they have the capability of also adding 5 GHz 11a/n capabilities to far more devices than we see offered up in the Sunday ads.
A recent mailing list discussion among wireless admins at a number of higher-ed institutions revealed a pretty common trend. Since my own wireless network makes the point, I’ll use it as the example. On a typical day, where a peak load of 10,000 simultaneous clients are cranking away in the air, no more than about 30% are utilizing the preferred 5 GHz side of the WLAN. For those not in the know, 5 GHz is a better deal for wireless clients in a properly designed network because there tends to be far less interference, fewer clients and triple-digit data rates available in 11n, and way more channels to make use of. So 70% of all clients slug it out in the channel-constrained 2.4 GHz spectrum, where 11g and the other, slower half of 11n reside. But it doesn’t have to be this way.
In my environment, the vast majority of those enjoying the 5 GHz connectivity that our big, expensive WLAN provides are using Apple products that simply ship with the right chipset. Again, my thanks to Apple for this. For many Windows platforms, you have to go out of your way to figure out whether a 5 GHz radio is even available for a given machine, and often it’s a not-so obvious upgrade option. Go to the Dell website and do some browsing; you can sort by screen size, hard drive capacity and processor, but not by available wireless adapter type. I did a quick scan of Best Buy’s online PC offerings and was briefly excited to see the option of sorting by "wireless capability," but the results were just bizarre. The first one in the list was a laptop running "BGN," and the last was a Lenovo IdeaPad that offered "Wi-Fi." Woo hoo. Wading through either site looking to upgrade bargain laptops to dual-band 11n is challenging, if not impossible. Like A/C and cruise control on even low-end vehicles, dual-band 11n should now be the baseline standard if the computing device supports it.
Is the joke on us in WLAN Nation for spending huge dollars on dual-band top-end 11n networks, when 70% (or something close to it) of clients are going to continue to come in the door for the foreseeable future with bargain wireless adapters, through arguably no fault of their own? It’s common knowledge that 802.11a 5 GHz never really gained much traction for many of the same reasons, but c'mon--this is the era of super-hyped dual-band 11n. The marketing math only delivers on its most impressive promises if the client part of the equation keeps up, and on lower-end computers (where most of my clients shop, evidently) it ain’t keeping up.
It’s time for the Acers, Dells and Lenovos of the world to do their part and retire the single-band wireless adapter everywhere they can, and help the wireless community at large to realize the benefits of 802.11n to the extent possible. Our networks are ready and waiting. Let's end the madness.Lee is a Network Engineer and Wireless Technical Lead for a large private university. He also teaches classes on networking, wireless network administrtaion, and wireless security. Lee's technical background includes 10 years in the US Air Force as an Electronc Warfare ... View Full Bio