If memory serves me right, Bob McMahon wrote: > Curious if iperf2 <https://sourceforge.net/projects/iperf2/>exhibits > similar behavior? It shouldn't have an issue with low packet rates.
I would not expect any problems with iperf2...the problems I alluded to are the result of a bad design choice in iperf3. Bruce. > On Mon, Apr 16, 2018 at 2:25 PM, Bruce A. Mah <b...@es.net > <mailto:b...@es.net>> wrote: > > If memory serves me right, Michael Fox wrote: > > The iperf3 bandwidth option doesn't seem to work (or perhaps I'm not > using > > it correctly). > > > > iPerf3 version 3.1.3 on Ubuntu server and Windows client. > > > > I'm trying to test radio links at various bandwidths, ranging from 32 > Kbps > > to 400 Kbps, and various packet sizes, ranging from 256 to 1520 bytes. > But > > setting the bandwidth down to the link bandwidth (or lower) doesn't > slow the > > output from the client. > > > > Example: In the example below, bandwidth is clearly set at 128K, but > > resulting bandwidth in 200K. > > > > How do I get the iperf client to only send at the specified rate? > > I think the #1 thing you should try is to get newer executables of > iperf3. Starting with iperf-3.2 (3.5 is current now) we re-tuned a > bunch of stuff with how the transmitter side paces stuff (or rather we > made it so it isn't so horribly broken). The use cases where this > really helps is for UDP, which tended to send packets in huge bursts, > and also had difficulty sending at very low bitrates as you are doing. > (iperf3 was originally designed for high-speed environments, such as > multiple-10Gbps.) > > If this doesn't work, sending smaller packets might help, although I > think controlling the packet size is part of your tests, so that might > not be feasible. > > Bruce. > > >> iperf3 -c 192.168.8.10 -u -l 1472 -b 128K > > Connecting to host 192.168.8.10, port 5201 > > [ 4] local 192.168.7.147 port 59396 connected to 192.168.8.10 > port 5201 > > [ ID] Interval Transfer Bandwidth Total Datagrams > > [ 4] 0.00-1.00 sec 25.9 KBytes 212 Kbits/sec 18 > > [ 4] 1.00-2.00 sec 24.4 KBytes 200 Kbits/sec 17 > > [ 4] 2.00-3.00 sec 24.4 KBytes 200 Kbits/sec 17 > > [ 4] 3.00-4.00 sec 25.9 KBytes 212 Kbits/sec 18 > > [ 4] 4.00-5.00 sec 21.6 KBytes 177 Kbits/sec 15 > > [ 4] 5.00-6.00 sec 24.4 KBytes 200 Kbits/sec 17 > > [ 4] 6.00-7.00 sec 21.6 KBytes 176 Kbits/sec 15 > > [ 4] 7.00-8.00 sec 24.4 KBytes 200 Kbits/sec 17 > > [ 4] 8.00-9.00 sec 23.0 KBytes 189 Kbits/sec 16 > > [ 4] 9.00-10.00 sec 23.0 KBytes 188 Kbits/sec 16 > > - - - - - - - - - - - - - - - - - - - - - - - - - > > [ ID] Interval Transfer Bandwidth Jitter > Lost/Total > > Datagrams > > [ 4] 0.00-10.00 sec 239 KBytes 195 Kbits/sec 0.049 ms > 0/165 (0%) > > [ 4] Sent 165 datagrams > > > > iperf Done. > > > > > > > > ------------------------------------------------------------------------------ > > Check out the vibrant tech community on one of the world's most > > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > > _______________________________________________ > > Iperf-users mailing list > > Iperf-users@lists.sourceforge.net > <mailto:Iperf-users@lists.sourceforge.net> > > https://lists.sourceforge.net/lists/listinfo/iperf-users > <https://lists.sourceforge.net/lists/listinfo/iperf-users> > > > > > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Iperf-users mailing list > Iperf-users@lists.sourceforge.net > <mailto:Iperf-users@lists.sourceforge.net> > https://lists.sourceforge.net/lists/listinfo/iperf-users > <https://lists.sourceforge.net/lists/listinfo/iperf-users> > >
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