perfsonar development work

["Jeff W. Boote" <>]

Stephan Kraft wrote:
> Hi Jeff,
>
> maybe it´s a more or less philosophical question.
...
> http://nmwg.internet2.edu/nmwg-tools.html
>
>     * available bandwidth:  the capacity minus utilization over a given
>       time interval.
>     * achievable bandwidth: the throughput between two end points given
>       a specific set of conditions, such as transmission protocol (e.g.:
>       TCP or UDP),  host hardware (e.g.: processor speed, bus speed, NIC
>       speed), operating system, system settings (e.g.: TCP buffer size,
>       txqueuelen setting),  and so on.
>
> with the measurements, we try to determine the "available bandwidth" by
> measuring the "achievable bandwidth" by optimizing the measurement itself.

Perhaps this is the main philosophical difference. In general, we think of our 
measurements as showing what was possible, without any explicit forecast. (As 
the economists say: Past performance is no indication of future earnings... ;) ) 
So, in our case - it is easy to think of iperf as *achievable*, since it shows 
what we were able to achieve at that given time.

I agree this can be a very complicated subject.

jeff