Sir ******,

Do not believe what these
web sites say.

Bandwidth is the total capacity
of your uplink. It
is the theoretical maximum at which
you can send and receive for all
your simultaneous connections.

Bandwidth is given to you
by the ISP.

Throughput, however, Is a measure
of your transmit/receive rate
for a given connection over time.
Throughput includes in its
calculation router hops, processing overhead, queues
, and what throughput the remote host's router
will communicate at.

In a perfect network, your throughput
would equal your bandwidth. However,
you will almost never see this - WAN or LAN.


So, if you connect to a computer
one router away, its throughput
should be high.

If you connect to a computer far
away, say 10 routers away, the throughput
will be lower.

Both connections, close or far,
are carried under the same
pipe, and share the bandwidth.

So, for example, if you have
a bandwidth of 100 kbps, you could
have theoretically 4 connections of
25kbps throughput, pending that
the destination hosts can perform equal
throughput - does the remote host
have enough bandwidth left, are there
traffic shaping or queues, etc.


You should not trust "speed test" web
sites. Those do not report your bandwidth.
Bandwidth is an agreement between you and
your ISP. **Speed tests will only report
the throughput between you and the web server
performing the test**. If the web server
is far away, the throughput will be lower
due to distance, and the fact that the
web server is receiving traffic from other
hosts on the Internet - some of its bandwidth
is being used for other connections, thus
lowering the throughput it can provide.

The data given to you by the 3com device
is just a measure of throughput. The 3com
device is calculating the number of bits
divided by seconds elapsed through the
transmit and receive buffers of the WAN
interface. It is an average measure.
It should be around the bandwidth you
purchased, but never the same. Remember, it
is just reporting the average throughput
of all connections. Throughput you can
consider as a slice of your bandwidth.
The bandwidth you purchased will ensure
that you can have multiple high-throughput
connections.

The 3com diagnostic page is not reporting bandwidth. Bandwidth
on routers is typically programmed by the
user. The user must type in the correct
bandwidth. The correct bandwidth value
is agreed upon by you and your ISP. Programming
the bandwidth only has an effect
on choosing the "best" route when using
dynamic routing protocols such as OSPF. You
should not worry about this for your product.

Your ISP is not sending you data containing
how much bandwidth you have, or at which
speed you are connecting. This may only happen
in complex configurations with QoS.

If you feel that you are not receiving
the correct bandwidth size, call your ISP
and see what they have allocated you. You
can even ask for a line test to see if there
is any un-necessary noise on your local
loop. Such noise would result in
lower throughput, but you would still be
contracted for the same bandwidth.

I hope this has cleared up any worries you have
Have a great day, thank you for your interest in 3com,
and feel free to contact us any time.

James S.

This reports on the ADSL status page a download speed of 8128 Kbps and an upload of 288 Kbps.

The various "speedtest" sites all give me a connection speed of about 2.5Mbps.