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How 802.11n Will Revolutionize Connectivity

InformationWeek Green - January 25, 2010
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Eleven drafts and 73 months. That's what it took to bring the final, ratified 802.11n standard to a network near you. Fortunately, it's worth the wait--11n is a quantum leap forward that, in our estimation, will change the WLAN game altogether. The Wi-Fi Alliance says 802.11n equipment will have five times the throughput and twice the range of legacy Wi-Fi gear; speeds are currently at 300 Mbps, with 450-Mbps and 600-Mbps systems on the horizon. The specification uses radio and antenna technologies in clever ways, while still providing support for legacy 802.11a/b/g devices.

Quite clearly, the target for 802.11n is to supplant wired switches. Still, the 779 business technology professionals responding to our InformationWeek Analytics survey on wireless LANs have reservations about using any WLAN as the main means of connecting end users to the network. Top among their worries: reliability (53%), speed and performance (50%), data security (48%), and consistency of experience (41%). There's also competition for the hearts and minds of CIOs who are working toward a more mobile workforce. Carriers like AT&T and Verizon have used the delay in delivering 11n to their advantage by building out their 3G networks. Cash-strapped IT groups moving from desktops to a mix of laptops, netbooks, and smartphones and seeking fast, ubiquitous mobility may well ask: Why spend money on 11n gear? Why not just leave the legacy WLAN in place in conference rooms for visitors and get data plans for employees?

These are legitimate questions that WLAN vendors will need to answer. On their side is the high cost of 3G data plans, which can run to $60 per month. Stripped-down $35 netbook deals are generally restricted to 200 MB or so of data per month. And you're depending on the public Internet to service enterprise end users who expect reliability comparable with wired Ethernet and will give IT an earful if they don't get it. They're also accustomed to, and often legitimately need, more bandwidth than 3G--or, for that matter, 802.11a/b/g--services can deliver.

"We are looking at a dual-mode strategy for 11n interior and carrier-based 3G/4G exterior," says Scott Ksander, executive director of IT network and security for Purdue University, which has about 30,000 unique wireless users per month. Ksander says WLAN usage is setting records this semester, with about 10,000 students and staff accessing the system per day. "Interior and office environments will require greater--near 100-Mbps wire speed--wireless bandwidth for the foreseeable future," he says. "The timeline between 11n work and 4G still looks to be a good fit for us. We certainly want 'ubiquitous,' but even 4G is not going to provide sufficient bandwidth for hour-to-hour standard office usage."

Ksander says Purdue's Cisco 11n deployment is providing the expected bandwidth and benefits, but he has his eye on 4G developments. For most organizations, the answer will be a mix of wired ports, 11n WLAN access, and more expensive 3G plans for the subset of employees who need them.

Yeah, We Have That

Clearly, 11n can provide stellar speed and better reliability, and prices for gear will continue to come down. But one caveat to upgrading is the inevitable design issues, including the possibility of bottlenecks on the wired side, inadequate power to access-point components, and difficulties retiring legacy end-user gear. More on those later.

As for security and consistency, problems in the original 802.11 standard were addressed with the introduction of Wi-Fi Protected Access v2--WPA2--based on the 802.11i amendment. The technology does exist to make 802.11 fully secure. And with 11n, users can have the same experience connecting to the network regardless of where they're physically located, key to improving satisfaction and reducing support calls.

The common denominator: standards.

InformationWeek has recently been critical of the state of technology standards. But we have to admit that vendors of wireless infrastructure devices, clients, and third-party applications are poster children for compatibility. When we asked the 779 respondents to our survey about their top product evaluation criteria, the ability to integrate wired and wireless networks came in ninth out of 16 choices, 10 points behind low capital costs and just above built-in diagnostic tools.

Credit goes largely to the IEEE and the Wi-Fi Alliance, which we profile in depth in our full report, available at analytics/80211n. Manufacturers rarely move faster than the alliance and its certification programs, because if they do, wireless clients--and their feature sets--risk not being compatible with infrastructure devices. The Wi-Fi Alliance promotes the features it thinks need to be made available. Consider the IEEE 802.11r and 802.11k standards, which help define how wireless devices on the move quickly and elegantly transition from one access point to another. Although these amendments to 802.11 were ratified in 2008, they're not yet implemented in vendor products because the alliance spec that addresses 11r and 11k hasn't been finalized. These technologies will be part of the alliance's Voice-Enterprise certification, expected later this year.

The upshot: The technologies that hit the marketplace, and the timing thereof, aren't up to individual vendors. Sure, we sometimes get frustrated with the lack of speedy movement, but you can't argue with the interoperability results.

That's not to say that functionality isn't sometimes released outside of the Wi-Fi Alliance's aegis, but most technologies that come to market in this manner are single-sided, meaning they work on the infrastructure without the participation of the client computer. One example is ClientLink, Cisco's foray into proprietary beamforming (a transmission technique). Though there is a standards-based beamforming spec under consideration by the Wi-Fi Alliance, Cisco decided not to wait.

While we know some IT pros are willing to trade openness for a proprietary functionality advantage, our recommendation is to insist on compliance with Wi-Fi Alliance certification programs. Systems that don't have certs will likely lock you in and may well cost more in the long run.

To read the rest of the article,
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What you'll find:
  • Our list of the Top 10 WLAN technologies enterprises care about. Hint: Speed matters.
  • In-depth discussion of rival architectural methods.
  • Rankings of WLAN vendors and prospects for wireless displacing Ethernet to the desktop.
  • Tutorials on security and compliance, client choice, education, and more.

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