If memory serves me right, Christian Sánchez wrote: > Hi Bob, > > Thank you once again for your reply. > > I have actually checked that Iperf2 and Iperf3 behave differently. When > I run the script which uses Iperf3, in the client screen an error > message comes up saying the following: iperf3:error - unable to connect > to server: Connection refused. > The script in the server (in the virtual box), just stop running. > > When Iperf2 is used, it goes like you describe: the client goes on > transmitting, and the script runs smoothly and receives packets. > > The script I run in the client machine is exactly the same, but changing > Iperf3 for Iperf2. > > I hope I can keep using Iperf2 for my purposes.
iperf3 uses a control connection, which is separate from any of the test traffic, to coordinate the actions of the client and server. You need to have the server process running when you start the client. You also need to be sure there are no mechanisms (such as firewalls, ACLs, etc.) that might prevent the control connection or the test traffic from passing between the two hosts under test. iperf2 and iperf3 are both under active development, but maintained separately. Their functionalities are similar, but different. Both of them (as well as other tools such as nuttcp) test bulk data transfers. As Bob wrote, there are other metrics to measure network performance, and which ones you want to measure will depend on why you want these measurements and what your intended workload is. Bruce. > El mar., 11 jun. 2019 a las 7:37, Bob McMahon via Iperf-users > (<iperf-users@lists.sourceforge.net > <mailto:iperf-users@lists.sourceforge.net>>) escribió: > > Well, I can speak from an iperf2 and WiFi perspective. > > The main performance things to measure are speed (latency) and > throughput. Throughput units is information over time, e.g. > megabytes/second. Speed or latency is units time. > > Most people measure throughput and think that's enough. Network > adapter cards are usually characterized by throughput as well, i.e > 1Gb/s, 10Gb/s, etc. But it's really not sufficient as the only > metric. Latency should also be measured. > > A "network power" metric can be better. It is something good > (throughput) divided by something bad (slower speed.) So it's > Megabits/second squared, hence the misnomer of "power." > > Speed is a bit tricky w/TCP but RTT gives hints at it. Note, we are > prototyping some direct TCP speed measurements. > > Other things to consider include the resources required to get the > information transferred. That's usually in memory, CPU, and energy > (for battery powered devices.) Iperf only hints at memory with > things like the CWND. > > More complex measurements deal with the shared nature of computer > networks. How fair is it when multiple TCP streams compete? Then > with WiFi it's more complex due to the access to the medium high > costs which can be amortized via aggregation technologies. > > Then there are things like traffic classes, i.e. prioritize one over > another in speed or throughput. > > There is more than this but this should get one new to performance > measurements started. > > Bob > > On Mon, Jun 10, 2019 at 7:40 PM Vidura Dantanarayana > <vidur...@gmail.com <mailto:vidur...@gmail.com>> wrote: > > Hi everyone!! > Bonjour!! > > I'm a beginner to performance testing and I was assigned to > measure TCP performance between two aws ec2 machines. Can I know > what kind of TCP related tests can be executed with iperf3? When > compared perf tool and iperf what differences do they have in > TCP performance testing. Have a nice day!! > > BR, > Vidura Dantanarayana. > _______________________________________________ > Iperf-users mailing list > Iperf-users@lists.sourceforge.net > <mailto:Iperf-users@lists.sourceforge.net> > https://lists.sourceforge.net/lists/listinfo/iperf-users > > _______________________________________________ > Iperf-users mailing list > Iperf-users@lists.sourceforge.net > <mailto:Iperf-users@lists.sourceforge.net> > https://lists.sourceforge.net/lists/listinfo/iperf-users > > > > -- > Christian Sánchez > > > _______________________________________________ > Iperf-users mailing list > Iperf-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/iperf-users >
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