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How does this page
calculate my connection speed?
Actually,
this isn't just one Web page, it's two Web pages, each with
a hidden data file in the header area of the page. When either
of these pages loads, it notes the time just before and just
after the data file loads, then uses this information and
the size of the data file to calculate the rate at which
the data arrived at your computer.
When the first of these two
pages was loaded, it did a rough calculation using a
small data file to provide an estimate of how long it
will take the second page, with its much larger data
file, to download. The second page, with its larger data
file, allowed the second page to calculate more accurate
figures for the Your Line Speed: box and Speed
Test Thermometer above.  Back to Top
Why
do I get different speed results each time I run
The Bandwidth Speed Test?
Like any major highway system,
the Internet information highway has many roadways and
interchanges, each with their own capacity and speed
limit, and, like highways for cars, sometimes you get
traffic delays. Just as you have to wait in a your car
while other traffic goes through at a traffic light,
data sent to your computer has to wait while other data
passes through routers, the Internet equivalent of an
intersection, on it's way to you.
You are more likely to run
into slow Internet traffic during peak use hours than
those times when fewer people are online, such as after
11 p.m. and before 7 a.m. When this page was being tested,
I found that the results on my 144Kbps DSL line results
varied from a consistent 120 to 135Kbps mid-morning and
afternoon, all the way down to 64Kbps during evening
peak-use hours. If you really want to find out what your
best possible Bandwidth Speed Test result is,
try loading this page at 3:00am on a weeknight, when
almost everyone is asleep when Internet use is at it's
lowest. (Friday and Saturday nights are not a good choice.)
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I
thought my Internet connection was supposed to be
faster. Why does the Speed Test come up with
a lower figure?
No Internet connection
ever performs at 100%. When we test loaded this page direct
from our test Web server across a two computer 10Mbps
local area network (LAN), our best result was 6.6Mbps
(6667Kbps). There is always some loss, and the
faster your connection is, the greater that loss is
going to be.
Next, this page can only
measure the time it takes the applications data--the
actual data file--to reach your browser. Wrapped around
that data is some overhead that can range from 2 percent
to 25 percent of the total data sent. There's no way
for the program built into this Web page to control or
discover exactly how much overhead was used to send the
page's internal data file, but generally the percentage
is small, and this page adjusts its figures up by 2 percent
to compensate. Nevertheless, the actual overhead may
be higher than expected, resulting in a depressed value
for the Kbps figure.
Also remember that your connection
to your ISP is just one part of the system that gets
data to your computer. Between your computer and the
server that sent this Web page there are probably a dozen
or more routers, communications links, and other network
components this page had to travel through. Each of these
components have a set capacity and speed at which they
can operate, and most of them handle network traffic
for thousands, even millions of computers every day.
The inevitable result is that all Internet traffic
encounters some sort of delay as it transits across The
Net, and that reduces the amount of data that gets funneled
into your connection in the first place.
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I'm
getting a big slowdown. Could my Internet Service
Provider (ISP) be the cause of my problem?
Perhaps.
The delay could be at your
ISP, or it could be elsewhere. (See the explanation above, but if you're consistently getting Bandwidth
Speed Test results that are substantially below expectations,
the root problem is most likely your ISP's fault.
While your dial-up modem,
DSL, ISDN or other Internet connection may be a dedicated
line, all of an ISP's connections get combined into one
or more shared connections. In most cases, these shared
connections have less capacity than the combined total
of all the customer connections they serve. Done judiciously,
this works better than you probably think. Since most
Internet users spend more time reading their email and
Web pages than they do downloading them, they're only
using a fraction of their connection's actual capacity.
Overbooking allows an ISP to combine several customer
connections into a single link that's smaller (and less
expensive) than the combined total of all the connections
they serve, without reducing the amount of data sent
to a customer when they are downloading data.
The problem is that some
ISPs, cable modem companies, and DSL providers take the
overbooking concept too far. They funnel so many connections
into a small combined connection that normal customer
demand overwhelms the capacity of the combined connection.
This is a particular problem during peak use hours, when
line speeds can slow to a crawl.
Unfortunately,
there is no remedy for this problem.
As competition in the high-bandwidth
Internet connection business heats up, you'll have more
options and your ISP will have more incentive to maintain
more reasonable overbooking ratios. Until that time,
however, your only options are to complain to your ISP
or switch to another Internet provider with a better
track record.
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I
have a 56K modem. Why isn't my download speed even
close to 56K?
There could be several reasons--and
most of them aren't your ISP's fault.
First
of all, static electricity caused by radio signals, power
lines, and other sources
interfere with most 56K modem signals, forcing them to
fall back to 42-50Kbps.
56K
modems also require a clean, straight through telephone
connection to the telephone
company's central office switching center. Phone company
line amplifiers that boost a telephone signal over a
long distance, PBX switchboard systems, and other phone
equipment alter the phone signal and force 56K modems
to fall back to speeds of 33.6Kbps and lower.
Finally,
the FCC doesn't allow 56K modems to use the full range
of signals that
phone company equipment can generate. They're concerned
that it'll cause static interference to other phone lines.
So no 56K modem in the United
States ever connects at 56K. Most 56K modem users
seem to connect at speeds of 44-48Kbps. Back to Top |
Internet
Speed Test - Frequently Asked Questions