North American Network Operators Group

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Download estimate tool?

  • From: Brennan_Murphy
  • Date: Wed May 01 15:55:24 2002

I'm looking for a tool to estimate file download times given a certain
set of variables: file size, available bandwidth, latency, receive window
and
circuit utilization.  To explain:

Suppose I have a single OC3 serving FTP downloads to individuals all over
the globe.  If the OC3 is not heavily utilized *and* I know the bandwidth
and latency between my FTP server and a client's workstation, I can
make a rough estimate of how long it will take for a file of a particular
size to download.   I could create a matrix in Excel  based on latencies and
bandwidths (factoring in TCP receive window sizes) and that would give
me a quick reference tool for gauging how long something should take
to download given a fair number of scenarios.  

But what if I want to enhance such a matrix to factor in what happens
to download times in those various scenarios as the utilization of
that OC3 approaches 100%?  I could make alot of edits to above
mentioned Excel matrix....but that would get tricky and visually
unappealing.   

Can anyone recommend a tool that makes it easy to play with the
above variables...a sort of modeling tool not quite so fancy
or expensive as Opnet for example?  Maybe a webpage with a
Java applet ?  Or maybe a fancy Excel file?

Thanks,
BM