Windows XP Hacks [Electronic resources] نسخه متنی

Hack 57 Check WiFi Network Performance with QCheck to Help Improve Throughput

XP can't tell you the true
throughput or your wired or wireless network. For that,
you'll need free, third-party software that can help
you improve throughput.

When you buy network
hardware, including a
hub/router and network cards, you're told that
hardware's rated speedfor example, 100 Mbps
for an Ethernet network, or 11 Mpbs for a an 802.11b WiFi network.

But those numbers only tell you how your network may perform in ideal
conditions; as the saying goes, "your mileage may
vary," and usually does. WiFi networks are
particularly finicky and are especially prone to being affected by
interference and other factors. Where you place your wireless access
point and PCs and how you position their antennas [Hack #55] can make a dramatic difference in
the actual speed of your network. So, you'll want to
know the true connection speed of your network, WiFi networks in
particular, so that you can optimize their performance when you
troubleshoot them.

But how can you find out your true network performance? If you have a
WiFi card, you can find information about your connection by
double-clicking on the small network icon in the
Notification Area (also called the
system tray). When you do that, the
Wireless Network Connection Status screen
appears, as shown in Figure 5-26.

Figure 5-26. The Wireless Network Connection Status screen

There's only one problem with that screen:
it's highly inaccurate. True, its little green bars
and Signal Strength indication give you a broad picture of the
relative strength of your network connection. But the Speed
indication isn't an actual measurement as far as I
can tell; it appears to tell you only your maximum theoretical
connection speed, given the nature of your hardware, and
doesn't reflect your true current connection speed.
When I use my WiFi network, it always tells me the speed is 11 Mbps,
even when actual, real-time measurement shows my true throughput is
less than half of that.

So, how do you measure the true speed of a network in your real-world
conditions? Get NetIQ's free QCheck
(http://www.netiq.com/qcheck/).
It performs a series of tests, including throughput and response
time, and gives you a good snapshot of your
network's real performance. When trying to optimize
a WiFi network, run QCheck on each PC on the network to get baseline
performance results for each. Then run the test for each PC after you
move the base station and PCs, change the positioning of the
antennas, and so forth, as outlined in [Hack #55]. That way, you'll
be able to fine-tune your network for optimum efficiency.

Once installed on every machine in your network, QCheck measures the
performance of the network between any two of your PCs. QCheck is
made up of two components: the console where you run your tests,
shown in Figure 5-27, and an endpoint, which runs
invisibly in the background on each PC on which
you've installed QCheck. While the exact metrics
vary from test to test, the program works by sending data from one PC
to another on your network. The data is then sent from the receiving
PC back to the originating PC, and QCheck measures the round-trip
time, calculates throughput, and displays the results.

Figure 5-27. The QCheck console

Note the throughput in Figure 5-27;
it's 5.128 Mbps. I was measuring the speed of my
WiFi network whie seated on my backyard porch, which is about 30 feet
and a wall away from my access point. Just to show you how much more
accurate QCheck is, the Wireless Network Connection Status screen
reported my speed as 11 Mbpsthe exact connection speed my
laptop would have if I were inches away from the wireless access
point. (And in actuality, the connection speed of a WiFi network,
even when devices are next to one another, is well under 11 Mbps.)

To run the QCheck tests, run the console and then choose the two PCs
between which you want to measure speed on your network. Only one
must be the PC with the console on it, but each PC does have to have
QCheck on it. You don't need to run the console on
each machine, because the endpoints are running on them invisibly in
the background; during QCheck's installation the
endpoints launch on startup.

You'll need to know the IP addresses of the PCs you
want to test. If one of the PCs you're testing is
the one running the console, choose localhost
for that endpoint. To find the IP address of other PCs on your
network, first go to that PC, right-click on My Network places, then
double-click on your network connection (it might read Local Area
Connection, for example, or Wireless Network Connection). Click on
the Support tab, and you'll see your IP address.

Once you choose the PCs you want to test, choose the specific test to
run. The best overall benchmark will be the Throughput test using
either the TCP or UDP protocols. If you happen to use IPX or SPX on
your network (some people still use these older protocols rather than
TCP/IP), you can do benchmark throughput tests using them as well,
though few home networks use those protocols. If you run any kind of
streaming media across your networkfor example, if you will be
using your network to play MP3 files or other digital music on a PC
and then stream it to another location in your housechoose the
UDP streaming test. Streaming media use the UDP protocol, so the only
way to test how they will perform on your network is to use the test
for that protocol.

Make sure to run your test multiple times, and, to be safe, run them
a half-hour or more apart. Because of the fickle nature of wireless
transmissions, you can find dramatic differences in throughput from
one moment to the next. For example, a few minutes after running the
throughput test shown in Figure 5-27, I ran it again
and was shown a throughput of 1.602 Mbps. That one test was an
anomaly, and other tests were more in keeping with my initial ones.

5.17.1 See Also

[Hack #42]