by Steven J. Vaughan-Nichols

Deciding When to Upgrade to 802.11n

Apr 21, 20088 mins
Data CenterNetworkingWi-Fi

As 802.11n slowly crawls toward becoming a wireless standard, IT managers have to decide whether it's the right time to switch. Unfortunately, the standard is stuck in draft status. Here's why.

You can never have enough money or a fast-enough wireless connection. We can’t help with the money part, but for Wi-Fi users, IEEE 802.11n—with its up to 300Mbps (megabits per second) burst speeds—is the answer.

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Well, it should be the answer. Deploying 802.11 is really not as simple as picking a networking vendor and pushing through a purchase order.

That’s because 802.11n has been stuck in standards mud-wrestling for years. As is so often the case in standards, two major vendor sides squared off over which group’s approach would become the one true—and thus money making—standard.

On one side was the Task Group ‘n’ synchronization, or TGn Sync. It counted Intel, Atheros Communications and Nortel among its members. On the other was World-Wide Spectrum Efficiency (WWiSE). Airgo Networks led this group. By early 2006, the pair had hashed out their problems in the Enhanced Wireless Consortium to reach a compromise that would become the official IEEE standard.

Well, that was the idea.

In 2008, we still don’t have an official 802.11n standard. Jonathan Gruber, In-Stat‘s research analyst for Wi-Fi and WLAN, said, “Currently, 802.11n’s status is draft 2.0, with the final standard expected in late 2008, early 2009.”

That hasn’t stopped almost all Wi-Fi vendors from releasing prestandard IEEE 802.11n products. This has raised some concerns, because the products may not be compatible with the final IEEE standard. If that’s the case, companies that invested in draft 802.11n access points (APs) and network interface cards (NICs) may face the prospect of replacing their high-speed 802.11n infrastructure. No one really wants to explain that to their CEO and CFO, do they?

Unfortunately, 802.11n’s standardization date keeps slipping. According to the IEEE 802.11 Official Timelines chart, the work-group approval for the new standard, which is the standard’s critical hurdle, is now penciled in for March 2009.

It may not make it.

Besides the numerous comments still to be resolved before draft 3 of the 802.11n standard appears, a patent problem is hanging over the proposal like a storm cloud on the horizon. To become an IEEE standard, everyone with a patent that touches that standard must sign a LoA (Letter of Agreement). The LoA states that the patent holder won’t sue anyone using his or her patent in a standard-compatible device.

That’s bad news to would-be 802.11n users. Commonwealth Scientific and Industrial Research Organization (CSIRO), an Australian government research group, has not signed off on 802.11n. Denis Redfern, CSIRO’s vice president of licensing, is reported to have said that the research body is “happy to confirm that CSIRO continues to be willing to license these patents on a worldwide basis to manufacturers of notebook computers, access points and other wireless-enabled products that would otherwise infringe the patents.” But Redfern also said that Wi-Fi vendors haven’t been willing to reach licensing agreements.

Indeed, Apple, Dell, Intel, Microsoft, HP and Netgear are attempting to overturn CSIRO’s patents. CSIRO has already won one lawsuit concerning these patents against Buffalo Technology. The group shows every sign of continuing its aggressive patent defense. And as for the IEEE 802.11n LoA? In September 2007, CSIRO refused to offer any amnesty to IEEE members that infringe on its patent.

The heart of this conflict? Money. Depending on whom you choose to believe, CSIRO wants a reasonable license fee for its technology—or it wants to charge OEMs (original equipment manufacturers) outrageous fees. Fees, that is, to be passed on to you as additional dollars per 802.11n device.

If this patent fight is the only remaining issue, it’s possible that 802.11n will become a de facto standard even if it still won’t be a de jure standard anytime soon. That’s because, as Molly Mulloy, public relations spokesperson of wireless OEM Broadcom, explained, “We believe that draft 2.0 of the 802.11n specification is very solid. All of the major technical items have been resolved, and only relatively minor wording issues remain. Therefore, we expect the final 802.11n standard to be ratified as planned in the second half of 2009.”

But What About My IT Budget?

So, should you upgrade now? Gruber said, “It is up to the businesses if they want to take the chance. Although a majority of the vendors are stating that their “draft n” products will be upgradable to the final standards through software updates, there is still some uncertainty in the industry.”

It’s noteworthy, Gruber continued, that, “the Wi-Fi alliance [the industry association promoting 802.11 wireless networking] claims, ‘At this point, it is not possible to determine whether forward compatibility’ with the final standard will exist.”

Mulloy, however, stated, “All of Broadcom’s draft-802.11n solutions shipped to date should be able to support the final specification with a firmware upgrade. Therefore, our existing products should continue to interoperate with Wi-Fi devices certified for the final 802.11n standard.”

Stan Schatt, ABI Research‘s vice president and research director for wireless connectivity, is also optimistic about 2008’s draft 2.0 802.11n equipment being compatible with tomorrow’s hardware. “At this point, with the Wi-Fi Alliance’s operability testing and certification in full swing, there are no longer any major concerns about buying prestandard equipment,” he says. If they haven’t done so already, most very conservative Fortune 500 companies will at least pilot draft-n products (if they haven’t done so already) although they might wait until 2009 and the final standard for massive deployments, according to Schatt. “Early adopters, such as health care and universities, are already involved in some major deployments involving thousands of APs,” he added.

Be that as it may, Gruber remains suspicious of vendors’ 802.11n claims, although he hasn’t tested any draft-n devices. Yet he cites independent reviews in which “many draft-n SOHO routers have not lived up to their claims in terms of speed. The enterprise vendors I have spoken to claim that their devices reach quoted speeds in real world tests.”

Another performance problem that most vendors shy away from explaining is that, while 802.11n is compatible with existing 802.11b/g WLANs (wireless local area networks), it does so at the expense of speed. Cisco, to its credit, addresses this concern head-on in its 802.11n Wireless Technology Overview: “An 802.11n network can incorporate 802.11a/g clients with minimal performance loss. However, as with today’s 802.11g networks, operating in a mixed environment that includes 802.11b clients can substantially affect throughput. (The throughput of today’s 802.11g networks may drop from 25 Mbps to as low as 7 Mbps when 802.11b clients enter the environment, and 802.11n networks will suffer a comparable performance decrease.)”

Seeing your overall WLAN performance actually drop when you had expected to see a boost is not a selling point. If you’re still using 802.11b equipment, for all practical purposes, you’ll need to replace it before “upgrading” to 802.11n.

It’s Not Just Performance

Another concern is 802.11n compatibility. For example, can a marketing executive’s Apple MacBook Air achieve true 802.11n speeds when it’s working with accounting’s Cisco Aironet 1250 Series AP? Both currently use draft-2 802.11n. In theory, both will be upgradable to the final standard. And, in theory, they’ll be able to talk with each other at sustained speeds of 100Mbps. In theory. A summer 2007 study by Wi-Fi vendor Colubris Networks showed that out of a survey of 200 senior IT professionals, 120 listed compatibility as among their greatest concerns about deploying 802.11n. It would seem they have reason to be concerned.

Of course, anyone who actually uses technology has a healthy wariness when it comes to the latest technology’s newest, fastest and greatest claims. Even in the best case for deploying 802.11n, however, its performance claims need to be weighed against other, more obscure financial and technological concerns.

Mulloy pointed out, “One obstacle that affects enterprise 802.11n deployments is power consumption. Most enterprise access points are powered over Ethernet cables. 802.11n uses more power than previous technologies—especially when operating on both the 2.4 and 5 GHz bands. This extra power consumption exceeds the capabilities of today’s Power Over Ethernet equipment (which uses a standard called 802.3af).” To support dual-band 802.11n access points, Mulloy said, an IT manager must use two PoE ports or upgrade the entire network to support the new PoE+ standard (802.3at). “That extra cost and hassle can be prohibitive to IT managers deploying wireless.”

Schatt agreed. “The power over Ethernet issue also is costly since current switching ports cover 802.3af, which doesn’t provide enough power for full utilization of 802.11n on most APs. Some manufacturers, such as Siemens, apparently have figured a way around this issue; others recommend workarounds or the addition of power injectors.”

For more on enterprise power consumption concerns, see The Greening of IT.

Another concern is in providing enough bandwidth to the 802.11n routers and APs for them to deliver sufficient speed to their clients. It’s generally agreed across the industry that 802.11n WLANs will need Gigabit Ethernet as their backbone to deliver acceptable enterprise performance.

All of this, of course, means one thing: higher installation costs. This leads us back to the beginning: You can’t have enough money or a fast-enough Wi-Fi connection. In the case of near-future 802.11n deployments, many businesses really might not be able to get enough of either one.