Build a Super-Fast 802.11n Wireless Network

But here's the rub: The 802.11n standard is still in draft form. A final standard isn't likely to be released by the IEEE until 2007 at the earliest. Even the second draft of the standard, which will incorporate hundreds of pieces of feedback from the first draft, isn't expected before the end of this year.

Such details haven't stopped wireless-equipment manufacturers from releasing a range of pre-802.11n wireless networking devices. They haven't stopped early adopters from trying them out, either.

In this Recipe, I'll give an overview of the emerging 802.11n standard and describe some of the devices that claim to deliver improvements in range and speed over 802.11g devices. Then I'll list the components you'll need to build a pre-802.11n network from scratch—as well as to integrate the hardware components into an existing 802.11g network. Finally, I will cover some best practices for implementing these standards. I'll also warn you about a few wireless-networking pitfalls that are best avoided.

Overview of 802.11n

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The 802.11n wireless networking standard achieves its enhanced speed and range by building on existing technology with some clever engineering. More specifically, the 802.11n standard can run on two frequencies at the same time: the 2.4 GHz frequency band used by 802.11g/b, as well as the 5 GHz frequency band used by 802.11a. In fact, 802.11n routers and cards generally have multiple antennas to allow for simultaneous data streams at different speeds; this feature is known as MIMO (short for Multiple Input/Multiple Output).

The first draft of 802.11n specifies support of speeds up to 270 megabits per second (Mbps), or five times that of a typical 802.11g network, which runs at 54 Mbps. Longer term, the speed of 802.11n devices is expected to double, reaching 540 Mbps.

Range gets trickier. While many manufacturers claim their 802.11n devices can deliver four times the range of 802.11g/b devices, these companies tend to use graphical representations of the range rather than specific feet or meters. By contrast, the IEEE's draft 802.11n specification clearly calls for an indoor range of 50 meters (roughly 164 feet), compared with 802.11g's 30 meters (or just under 100 feet). Of course, even these are only rough estimates. A number of variables can come into play, such as the density of building materials, the location of access points, and the position of the wireless card. Outdoor range is even trickier, particularly because data speed tends to drop off precipitously with greater ranges, regardless of the standard.

Ingredients

To get started with 802.11n, you'll need the following gear:

To reach the potential speed of 802.11n's 270 Mbps, each device in the path to an end user's computer will also need to be upgraded to a gigabit Ethernet infrastructure. Any device or wiring supporting only 100 Mbps would create a bottleneck. At a minimum, you'll need: Gigabit ethernet router/switches/hubs; and Gigabit ethernet network cards.

Hardware

The first MIMO pre-802.11n routers and cards were released earlier this year. The suppliers are the same manufacturers that dominate the existing consumer and commercial wireless market, including Belkin, Buffalo Technology, D-Link, Linksys, and Netgear.

If uncertainty over the implementation of a draft standard wasn't enough, there are three main camps of chipset manufacturers: Broadcom's Intensi-fi, Marvell's TopDog, and Airgo's Gen 3. Both Broadcom and Marvell's chipsets are based on the 802.11n draft specification. Airgo's Gen 3 chipset uses MIMO technology for similar performance, but doesn't adhere to the 802.11n draft.

A quick survey of the manufacturers seems to show a more-or-less even split among vendors. Linksys and Buffalo use Intensi-fi. D-Link and one of Netgear's devices use TopDog. And Belkin and a second Netgear device use Gen 3.

Each company offers the standard assortment of wireless adaptor cards, as well as a few options for routers and access points. Most manufacturers marketing pre-802.11n equipment offer both lower-end "consumer" routers and higher-end "commercial" routers. The consumer-oriented devices generally come with an integrated four-port 10/100 Ethernet switch, which seems a bit off target on a device claiming speeds up to 270 Mbps. The higher-end commercial routers command their higher price point by including additional networking and security features, such as VPN capability and support for gigabit Ethernet.

Also, several manufacturers offer access points without integrated switches. Linksys even offers a power-over-Ethernet option for its access point, a good candidate for placement in tough-to-reach places. Building a MIMO/pre-802.11n Network

For the purposes of testing a pure pre-802.11n network, I used a Linksys WRT300N router and a Linksys WPC300N wireless adapter card. Here's a look:

Configuring the Linksys router via the installation software and the quick start guide went fairly smoothly, other than some quirks with security set-up. Once the device was up and running, I installed the Linksys wireless adapter card, which went flawlessly. I have to confess, it was pretty cool to see a (theoretical) 270 Mbps connection:

But the good times didn't last forever. After just a few moments, the connection speed dropped down to 27 Mbps, then fluctuated up and down for what seemed no reason at all. My laptop remained just a few feet away from the router. The router has three external antennas, and adjusting their direction seemed to help the signal a bit. But it's certainly an inprecise science.

That said, the connection never dropped completely. I was able to download test files quickly and surf reliably from as far as 60 feet away through several thick masonry walls.

Integrating Pre-802.11n Gear with an Existing 802.11g Network

If your goal is to expand an existing 802.11g wireless network with pre-802.11n components, you have a few options. I strongly recommend that you add only pre-802.11n devices, as opposed to other MIMO devices, such as those running the Airgo Gen 3 chipset. That's because Airgo has confirmed that attempting to concurrently run an 802.11g wireless network alongside a MIMO network will not work reliably.

Again, in my tests, I used the Linksys WRT300N pre-802.11n router and the Linksys WPC300N pre-802.11n wireless adapter card. This time I had them running alongside a Linksys WRT54G 802.11g router and two different adaptors: an integrated 802.11g adaptor and an 802.11b card.

Both the integrated 802.11g adaptor and the 802.11b cards connected to the Linksys WRT300N pre-802.11n router without a hitch. I saw speeds right around what you would expect for a typical connection to 802.11g and 802.11b router, respectively.

Also, the Linksys WPC300N pre-802.11n wireless adapter card had no trouble connecting to the Linksys WRT54G 802.11g router. As expected, it displayed a connection speed of 54 Mbps.

(For an insightful, in-depth discussion of interoperability between various pre-802.11n devices, as well as between pre-802.11n and 802.11g network components, check out this article from Extreme Tech called Real-World Interoperability Tests of Five 802.11n Routers.)

Performance: Speed and Range

To keep your customers from being disappointed after spending money for new equipment, it's wise to manage their expectations about what level of performance improvement can—and cannot—be reasonably expected.

If your customers already have a FIOS, DSL or cable-modem broadband connection to the Internet, you'd do well to advise them to not expect to see a significant change in surfing and download speeds by upgrading to 802.11n. Even the fastest FIOS and cable modem speeds—which generally top out at 30 Mbps—are well within the capabilities of a 54 Mbps 802.11g router, particularly over short distances.

I did a couple of unscientific speed tests by downloading a few large files from a server on my internal network and running Speakeasy's Speed Test. The tests gave the pre-802.11n components a slim but noticeable edge over the 802.11g setup. But the slight improvement in speed is hardly enough to make up for a price tag that averages about double that of the equivalent device running 802.11g.

To compare the range of the 802.11n router with that of an 802.11g, I did a bit of old-fashioned "walk around with the laptop" testing. I found very little difference, both inside and outside. In fact, the older 802.11g had a 15 percent to 20 percent more range inside, while the newer 802.11n router had a slight edge outside.

The Upshot

Like most emerging technologies, the 802.11n standard and MIMO offer good news tempered by bad. The good news: The pre-802.11n devices I tested seem to show that, under ideal conditions, these devices can deliver significant speed boosts over 802.11g configurations.

The bad news: There's a very real possibility of being stuck with equipment with no direct upgrade path to the final standard for 802.11n.

The upshot: If your customers insist on taking a chance on the standard for the ability to squeeze out a few extra feet in range or a few more Mbps in speed, today's equipment will work. But if they can wait, you may want to advise them to let the dust settle around 802.11n. The second 802.11n draft will soon be complete, so we'll all have a clearer idea on what's to be. Plus, the next wave of products are sure to be released directly after that. So if they can wait another year, they'll get the real deal with a final standard.

There's a fine line between being an early adopter and being a beta tester, and the current crop of pre-802.11n components are likely to have your customers straddling that line. As long as customers understand that, however, you should be fine either way. Success here really depends on your customers' patience—or lack thereof.

PETER HAGOPIAN is a Philadelphia-based freelance writer who has covered technology and music for more than a decade.