Re: transmission rate cap

Jan Engvald LDC (
Fri, 16 Sep 1994 16:17:22 -0400

> Should I be looking for a reason for the very slow data rate (< 1 fps) and
> high packet loss (95%) I experience off the NASA Select feed at my site or is
> this something everyone is experiencing. My previous experience has been
> pretty good audio fidelity but recent performance is unintelligable ... Gav

I often also get high packet loss, when it is more than 30 % it is rare
to hear any complete sentence. Investigations tell that most of the time
this is due to an overload of the link between
( and (

If you have a MS-DOS PC you can easily find the bottlenecks of a path
using the trace route function of PDTSTNET, just call

pdtstnet hopcheck=<name or IP nr>

and the path will be traced 3 times in a few seconds (10 seconds
actually). Where you see a jump in delay times is where the bottleneck is.
I have often seen a 1000 ms increase at the abovementioned link,
other links add less than some tens of milliseconds per link.

PDTSTNET is available from
and other simtel mirrors.

You can also use other trace route routines, but they often take a minute
or more to complete when the packet loss rate is high.

Jan Engvald, Lund University Computing Center
Address: Box 783 E-mail:
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