Does 802.11n spell the 'end of Ethernet'?

Analyst says 802.11n is 'good enough' for wireless client access

The 802.11n wireless LAN standard may finally provide enough throughput to make that RJ45 jack in the wall as outmoded as a gaslight fixture. What do you think?

Is the advent of the 802.11n wireless standard the “end of Ethernet” - at least in terms of client access to the LAN?

That’s the provocative title, and thesis, of a new report from Burton Group, written by senior analyst Paul DeBeasi. He began looking into the question when he heard a growing number of clients asking whether it was time to discontinue wired LAN deployments for connecting clients. Would 11n, the next generation high-throughput Wi-Fi, make the RJ45 connector in the office wall as obsolete as gaslights?

On the surface, the question seems to answer itself. Enterprises almost as a matter of course have been focused on making the wired connection to clients as capacious as possible, at as much as 1Gbps Ethernet. The first WLAN products based on draft 2 of the 802.11n standard are demonstrating throughput of 150Mbps to 180Mbps, which has to be shared by the number of clients connected to a given access point.

In addition, DeBeasi’s report also details how WLANs introduce some novel problems, such as RF management and new security risk vectors, and complicate existing ones, such as network management and IT training. All of which makes one ask, “Why Fi?

DeBeasi has a simple answer. “The mobility piece,” he says. “I have a 21-year-old, and an 18-year-old, and they have never plugged [a computer] into anything in their lives. And I have wired Ethernet in my home,” DeBeasi says. “They all expect ubiquitous Wi-Fi. That’s the unstoppable force that’s pushing us forward.”

“Mobility is already a priority for my organization,” says Jeffrey Allred, manager, network services, at Duke Comprehensive Cancer Center, part of Duke University Medical Center, Durham, N.C. “MDs, PhDs, and researchers in general are all over the place most of the time and being ‘connected’ from wherever they may be is critical.”

It’s also a priority at Grant Thornton LLP, Chicago, the U.S. member firm of the global accounting, tax and business advisory firm. “As a professional services organization, it is important for our people to collaborate at anytime and anywhere,” says Michael Ruman, IT messaging manager for the firm. “Adding wireless to the corporate infrastructure has allowed our professionals to move from one physical office to another and conduct meetings or work sessions… anywhere within the organization.”

The Burton report tackles the performance differences between Gigabit Ethernet and 11n head-on.

“However, does greater throughput really matter to most enterprise users who are not transferring enormously large files?” the report asks. “We found that although 802.11n was slower than Gigabit Ethernet, the download time difference was negligible. Even with 20 users per [access point], the file download times ranged from two to eight seconds -- still satisfactory for most users… Burton Group expects that 802.11n will eventually approach the performance levels provided by Fast Ethernet and that, for many enterprises, 802.11n throughput will be good enough.”

Does DeBeasi think “good enough” is, well, good enough for enterprise nets? “If you look at 11n with 150Mbps and 20 users sharing the access point, they get 7Mbps average throughput,” he says. “They don’t get that in their homes with DSL and cable modems. It’s time for people to reset their thinking.” As part of that reset, DeBeasi points to the report’s comparison in VoIP performance between Gigabit Ethernet and 11n in latency, which is the one-way delay between a sender and receiver on a network, and in jitter, which is the amount of variation in the arrival times of VoIP packets. In both cases, he acknowledges, 11n is considerably worse than Gigabit Ethernet: latency is roughly 20 times that of Gigabit Ethernet, and jitter can be as high as 150 times.

“But who cares?” asks the report. In both cases, the absolute value of the 11n results is still only a small fraction of the wireless VoIP “budget.” Both latency and jitter in 11n should be “good enough,” DeBeasi argues.

Allred and Ruman agree. “I think for the bulk of users, this would be sufficient,” Allred says. “In my environment – at this time – it’s not the bandwidth but the ability to connect from all locations that is key.”

“Currently I think [150Mbps to 180Mbps] is plenty,” says Ruman. “Most companies are still using 100Mbps switches and have not made the jump to Gigabit past the data center anyway.”

“Personally I feel it will have to go higher than 150Mbps to 180Mbps,” says Mitchel Prevatte, CTO/CSO for Coppin State College, Baltimore, Md. “In a switched world, you’d have all of that as useful bandwidth for each user… Also, I’m not sure of propagation distances of that high bandwidth. It could take lots and lots of access points."

Ruman is keenly aware that enterprise applications are changing, and the changes will demand that 11n keep pace in bandwidth. “In the future, I think speeds will need to be close to gigabit speeds,” he says. “More rich media applications, video collaboration, and [other] higher bandwidth applications are desired by enterprises. You can’t tell users than application or service they use at their desk is unavailable wirelessly.”

And for some specialized needs, 11n is still not good enough. Hess Corp., Houston, uses an array of demanding geophysical research applications. “[Even] 200Mbps is not fast enough for our application delivery model for scientific applications,” says Alan Mayo, external services coordinator for Hess.

The report concludes the added challenges of WLANs – increased complexity for net management and security, the need for radio management tools – are being overcome with a growing array of new tools. And in the not too distant future, LAN switches will incorporate support for wireless clients as a matter of course. As that happens, “it will become more difficult to purchase separate wired and wireless products,” DeBeasi writes.

In the meantime, large-scale enterprise WLAN projects coming to fruition over the next 12 to 18 months should look hard at 11n, he says. One client plans to deploy 1,000 access points next year, and currently they will be 11g devices, with a top throughput of 20Mbps to 25Mbps. “By fall of 2008, a lot of laptops will have 11n embedded. Do you want to have 11n laptops rolling into your enterprise, and unable to use the WLAN except as 11g clients?” he asks.

Laptop refresh cycles and WLAN deployments need to be factored together, which may it make attractive to deploy an 11n infrastructure soon, which can be used by 11g clients, but also used as those clients transition to 11n interfaces.

DeBeasi admits 11n comes with an added premium, which seems to vary now from 20% to 100% over 11abg products. “But those are list prices,” he points out. “Over the next six months, these will decrease. Over the next 12 months, as volumes come up, we’ll see a pretty fast drop in prices. By first or second quarter next year, it will be an incremental premium of 20% to 25%.”

So, is 11n the end of Ethernet for client access? Our users say no - or at least, not yet. But some say the writing is on the wall.

“I believe that once the WLAN is as reliable as wired access, you will begin to see enterprises move away from wired infrastructures, based on cost savings alone (in both wire and labor),” says Allred. “But that being said, I don’t think this change will come overnight.”

“11n is not the ‘hard wire killer’ yet,” says Ruman. “Some users still need wire speed and population density of cubicles is still too great in some areas to provide a comfortable wireless experience.”

“I don’t think the end is here,” says Mayo. “Ask me again in 10 years.” Coppin State’s Prevatte thinks the same. “I don’t see wired Ethernet going anywhere soon," he says.

DeBeasi’s thesis has been savaged on some online forums (one online poster wrote "You will take away my Cat6 only if I am dead. You better double kill me so I don't haunt you to get my cables back").

"11n is the beginning,” he says. “Maybe it’s time to not pull that cable…”

Learn more about this topic

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802.11n starts its wireless stress test at Morrisville State

Cisco unveils 802.11n wireless LAN access point for enterprises

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