Re: [pacnog] Broadband bandwidth test tool

[joelja <joelja@uoregon.edu>]

Joe Abley wrote:
> 
> On 2-Aug-2006, at 00:44, Tevita Kupa Fifita wrote:
> 
>> I’m looking for some tool or program that can tell me the exact
>> bandwidth of a broadband connection. I want to test the bandwidth (not
>> speed) on a dsl broadband connection from the customer side to my side
>> (isp side). I have looked around and can only find speed tests but not
>> bandwidth tests.
> 
> On the customer side, seed a copy of whatever played on TV in the US
> last night using any bittorrent client, then see how full the link gets.
> 
> I'm only slightly joking.

Topgear please I need seeds... Thanx.

>From my perspective the definition of bandwidth and speed are
superficially the same. If you want to call speed, the link speed, which
is related to the symbol rate you can support and you want to call
bandwidth the symbol rate expressin bps minus framing overhead or other
costs then I'm cool with that. If you want to call what you're trying to
measure achievable maximum throughput then I think that's what your were
trying to measure, hence my previous question.

So there are some nice tools such as ttcp that can help you measure
maximum possible throughput, but as with most physics experiments the
results depend on the location of the observer and the sensitivity of
the equipment. that's also an active measurement, using the link for
anything else would color the experiement, and moreover successful
testing would probably render the link unusable. other tools such as
pathcar or pchar are designed to measure latency variation as a proxy
for the bandwidth available on a given link (ie the cost of putting the
next packet on the link is directly related to the speed of the link),
they're not very accurate, and the faster the link speed the harder it
is to measure.

in anything remotely long-haul link bandwidth-delay-product and the
overall size of the data you're trying to move (if you're using tcp)
will play a role in your measurements and overall performance.

joelja

> 
> Joe
> 
> 
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Joel Jaeggli             Unix Consulting              joelja@uoregon.edu
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