802.11n keeps movin', movin', movin'

The wireless standard takes a big step forward with the IEEE's vote on the latest draft

The recent vote of the IEEE 802.11n Task Group to move forward with a second draft was, well, anticlimactic. The lack of surprise with what until quite recently was one of the most contentious standards efforts ever is in and of itself surprising. But what's at work here is much more than a bunch of techno-nerds agreeing to finally agree. What we really have here is a profound shift in attitude on the part of many key players, driven partially by expediency, or, um, I mean reality. And it's also going to reshape the WLAN market, residential and enterprise, once again.

The whole .11n process was taking too long, and too many of the players were producing incompatible "Draft n" implementations. Since interoperability is the province of the Wi-Fi Alliance, it seemed likely that this group would need to step in and define exactly what "Draft n" means -- and now they have. The recent decision by the alliance to issue an interim spec for the interoperability of higher-performance wireless LAN technology has reshaped the playing field. Note that the alliance is a trade association, not a standards body, but is made up of many of the same players as in 802.11n. The alliance has a long history of stepping in when a formal standards process has bogged down, and the interim .11n spec, due at the latest in June, just continues this tradition.

This decision is really going to help in getting the many benefits of .11n into the hands of users sooner than might otherwise be possible. Among these benefits are higher throughput and greater range, but three other important elements are worth noting as well: upgradeability, GigE discontinuity and capacity.


I've spoken with a number of chip and system vendors and have heard that many of their current "Draft n" products will be software upgradeable to the interim Wi-Fi spec. You may recall this was one of the more controversial claims made by the Draft n crowd back when these products first started to appear in the second quarter of last year.

The big problem, from my perspective, was that the vendors wouldn't and, indeed, couldn't make such a guarantee. The Wi-Fi spec has changed all of this. It is, in effect, an upgrade of Draft n, and I expect a good number of products, but by no means all of them, to be upgradeable at this point.

GigE discontinuity

Note that gigabit Ethernet (GigE) will be required on .11n products. 100Mbit/sec. Ethernet can indeed move 100Mbit/sec., but that's including packet overhead, retries and a range of elements other than data payload. I expect the Layer-7 performance of many .11n products to exceed 100Mbit/sec., meaning GigE is essential.

It's time to upgrade those switches if you've not already done so. But note this creates a discontinuity in demand, making most current WLAN switches obsolete and opening the door to new entrants. Indeed, we expect to see new WLAN companies formed to take advantage of .11n, all because of the need to replace existing equipment.

Capacity, not throughput

One argument I've heard against .11n is the rather tired "no one needs 100Mbit/sec. on a wireless LAN." Anyone making such a statement is missing a fundamental point about wireless: The issue is capacity, not just throughput. Higher raw speeds and more reliable signals mean that any given user gets his or her data through in less time, meaning more time left for you and me. Higher speed is really a means to a more important end, and that is getting more users on the air in the limited bandwidth available.

In short, .11n, probably as embodied in the interim Wi-Fi spec, will be the only protocol that matters going forward. While .11a, b and g are hardly dead, products based on those protocols will be hard to find in a year. The fundamental backward compatibility of .11n deals with this issue quite effectively, but my guess is that most packets going over the air will be .11n within two years. And we should also point out that .11n is it for now, and likely will be it for a long time. There are no other big protocols on the horizon, although additional enhancements to .11n can of course be expected. Throughput on .11n can in theory reach 600Mbit/sec., and, in theory, perhaps even more than that.

So, if you've been putting off the purchase of a WLAN because of the rapid pace of change in wireless technology, well, I'm not going to lie to you; there's a lot of change yet to be seen as there are still more new 802.11 standards on the horizon. But 802.11n represents the last major change we'll see for some time, so get ready to jump in.

Craig J. Mathias is a principal with Farpoint Group, an advisory firm specializing in wireless networking and mobile computing. He can be reached at craig@farpointgroup.com.

Copyright © 2007 IDG Communications, Inc.

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