Subject: [NEXTEL-1] Fastest Wi-Fi You Can Actually Buy

From: [email-masked]
Date: Sat, 20 Dec 2003 01:23:37 -0500

Fastest Wi-Fi You Can Actually Buy

NEWSFACTOR SPECIAL REPORT

By Jay Wrolstad
Wireless NewsFactor
December 19, 2003

How fast is fast enough? That is the question buyers of Wi-Fi wireless local
area network equipment are asking themselves in the wake of new standards
and claims by vendors that they can deliver data at eye-popping rates.
But the real question may be, is there a demonstrated need for speed above
and beyond that currently offered by basic Wi-Fi standards?

Most data transmission rates for Wi-Fi equipment reflect results achieved in
a lab under ideal conditions. In reality, the systems for small business and
home networks rarely approach those rates -- for a variety of reasons.

Hype vs. Reality
"All of the talk about speed is misleading," says Gartner analyst Ken
Dulaney. "It's difficult to quantify because as a shared medium, Wi-Fi is
affected by the amount of traffic on the network." Users typically
experience signal degradation as they move further from the access point, he
explained, with speed decreasing fourfold as you double the distance.

Buyers should consider that they might get a link rate of 54 Mbps at a range
of 60 feet, dropping to about 11 Mbps at 100 feet, Dulaney told NewsFactor.
At 100 feet the link rate, or maximum throughput, is 11 Mbps for 802.111b,
and 18 Mbps for 802.11g or 802.11a, although both a and g have higher speeds
at the center.

Used in the same footprint, 802.11a and g are roughly three times faster, on
average, than 802.11b, depending upon the distance to the access point and
the amount of interference. The actual speed is about half of the posted
link rate -- and the more users on an access point, the slower the
throughput rate.

What's Your Line?

Still, such vendors as Linksys (See http://www.linksys.com/) and Netgear
(See (See http://www.netgear.com/) advertise Wi-Fi products that are faster
in theory (108 Mbps) than a T1 line (100 Mbps). But tests show that the most
they really can deliver in a typical user situation is about 25 Mbps.

The 54 Mbps promised in 802.11a is a composite bit rate, not what the
end-user gets. Netgear, for example, is using a new chipset from Atheros
(See http://www.atheros.com/) that they say will double the rate to 108
Mbps. But, said Dulaney, there is no standard for this technology and no
interoperability. "There's no way to tell how far that rate extends from the
access point. And the link rate of 108 Mbps means the throughput rate would
be about half that.

For most users, said Dulaney, it is more important to upgrade the line going
out of the house, which is typically a couple of kilobits per second.
"Companies like Linksys and Netgear are offering mismatched speeds, since
the speed of the line from the house determines the network-connection
speed," he said.

Wi-Fi Options

There is not much discrepancy in terms of speed with the accepted Wi-Fi
standard, contends Ira Brodsky, president of Datacomm Research. He agrees
that the distance between access points and the number of users has a
significant impact on transmission rates.

"In the enterprise, with a Wi-Fi network in a closed environment and a
gigabit backbone, you can probably reach 100 Mbps with that new technology,"
Brodsky told NewsFactor. "But are there applications that require that type
of connection?"

There is much more overhead in wireless networks than in wired systems, with
more bits in the pipe in a shared system and users moving into and out of
range. As a rule of thumb, Brodsky said, there should be no more than six
users per access point to achieve optimum speed.

For the most part, says Dulaney, upgrading to 802.11a or g from 802.11b
probably is not worth the effort or expense. "802.11g is a special case,
though, evolving from efforts to provide backwards compatibility with
802.11b, and is a technology applied to 2.4 GHz, he points out.

As such, 802.11g is better for the home than a business setting. With a
mixed environment of 802.11b and g, the actual speed will be a lot closer to
that delivered by b than g. "The best bet for speed is to use 802.11a and
avoid mixed clients," he said.

Bragging Rights

The best Wi-Fi options depend on where the network is deployed, Brodsky
said. When the Wi-Fi hype erupted about two years ago it was all about
buying an 802.11b access point and adapter and getting the system up and
running. "Now there's a need for a better managed solution that provides
connectivity throughout an organization's campus and advanced tools to
detect the number and location of access points, as well as pinpoint rogue
hot spots."

Claims of top speeds are a marketing tool by vendors looking for bragging
rights, said Brodsky. What is really needed is a way to increase throughput
for end-users, and the applications for higher-speed connections. Current
research is examining ways to develop access points with multiple channels
to segregate users and thereby maximize throughput, he said.

"As for who's fastest, there will always be contention over vendors' claims.
Most Wi-Fi providers use comparable chipsets, so the speeds will be pretty
much the same," Brodsky said.

Dulaney suggests that for most Wi-Fi shoppers it would be better to buy
cheap and wait until the technology matures. What applications are out there
that require these high speeds?" he said. "Is there really a need for the
new standards when users can already handle applications like media
streaming just as well as on 802.11b?"

 http://www.wirelessnewsfactor.com/perl/story/22901.html

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