Please note that I am not asking for well known usual bandwidth monitoring tools like ntop, iperf, vnstat etc.
I would like to measure periodically and reliably the max. available bandwidth of a network uplink, but without "stealing" bandwidth and without disturbing other traffic on this same connection.
Is this possible at all?
Usually I do adhoc measurements with rsync or iperf, but from what I understand these kind of tests also saturate the bandwidth of the connection and this makes it not possible to do this, say, every minute.
I have a not so stable uplink with several remote desktop connections and every bit counts, but I also would like to collect meaningful logfiles to be able to present information about this connection not offering the contracted bandwith at all.
So how do I collect this data without killing the already weak network connections going on here?