Re: [Iperf-users] TCP performance Testing Question
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. Cheers, Christian El mar., 11 jun. 2019 a las 7:37, Bob McMahon via Iperf-users (< 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 > 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 >> https://lists.sourceforge.net/lists/listinfo/iperf-users >> > ___ > Iperf-users mailing list > 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
Re: [Iperf-users] Traffic test changing payload in virtual box
Hello, Thanks for your reply Bob. I am trying to get it working the way I have explained...the only thing is that my raw socket script stops running when I execute Iperf client: - if I run my own packet transmitter, I can send as many packets as I want and the raw socket script does not end, just keep waiting for more packets to receive (I am using the function "recvfrom") -when I execute Iperf, it receives one packet, and just ends almost immediately (like as I had done ctrl+c) Any hint on why this happens? Might it the way Iperf handles the connection? Cheers, Christian On Sat, 8 Jun 2019, 00:15 Bob McMahon, wrote: > It sorta makes sense but not sure. My answers are from an iperf 2 > perspective. > > Currently, there is no way from the command line to add a header to the > UDP payload. It would have to be done in source code or by something like > linux tc or ip tables. > > The iperf client doesn't require an iperf server for it to send packets. > It just needs arp to be resolved. So a VB can receive traffic from client > (or transmit) only. > > Yes, I think you can get the measurements from the second computer > assuming the packet payload has what's expected for it to make the > computations. > > Bob > > On Fri, Jun 7, 2019 at 9:22 AM Christian Sánchez > wrote: > >> Hi, >> Probably the topic is not very helpful...Let me explain my situation in >> more detail: I need to modify the UDP payload generated by Iperf, so I can >> add an additional header to it. My idea is to run an Iperf client in a >> computer, and use this client to send traffic to a virtual box in the same >> computer. In the virtual box I would be running a script using a raw socket >> to receive the data. After receiving it, and adding the header, I send it >> to another Iperf server (in another computer), which would receive the data >> after having removed the header. >> My questions: >> I don't have a clear understanding of the working details of Iperf, does >> what I have explained above make sense at all to you? >> Can I expect to get traffic in the VB from the client even when I'm not >> running any server in the VB? >> If by any chance I finally get traffic in the second computer, can I >> expect it to perform correct measures from the traffic generated by the >> client? >> >> Cheers >> Christian >> ___ >> Iperf-users mailing list >> Iperf-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/iperf-users >> > ___ Iperf-users mailing list Iperf-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/iperf-users
[Iperf-users] Traffic test changing payload in virtual box
Hi, Probably the topic is not very helpful...Let me explain my situation in more detail: I need to modify the UDP payload generated by Iperf, so I can add an additional header to it. My idea is to run an Iperf client in a computer, and use this client to send traffic to a virtual box in the same computer. In the virtual box I would be running a script using a raw socket to receive the data. After receiving it, and adding the header, I send it to another Iperf server (in another computer), which would receive the data after having removed the header. My questions: I don't have a clear understanding of the working details of Iperf, does what I have explained above make sense at all to you? Can I expect to get traffic in the VB from the client even when I'm not running any server in the VB? If by any chance I finally get traffic in the second computer, can I expect it to perform correct measures from the traffic generated by the client? Cheers Christian ___ Iperf-users mailing list Iperf-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/iperf-users
