perfSONAR User Q&A and Other Discussion

[Brian Tierney <>]

I believe it means that the packets are not arriving in the order they are sent, and that the sequence number is off by 5 packets. (SP = 5).

This sometimes happens with bonded interfaces/links.

On Tue, Jul 19, 2016 at 11:14 AM, Kathy Benninger <> wrote:

Greetings!

I am doing iperf3 UDP testing on a problem path and have some questions about the output reporting on the receiving end.  I haven't been able to find explanatory docs so would appreciate a link and/or a clue.

Thanks!
Kathy
-----------------------------------------------------------------------------------------
Version info-----------------------------------------------
iperf3, downloaded and built 17-Jul-16 on both machines:

iperf3 -v
iperf 3.1.3
Linux <remote.host> 3.2.0-88-generic #126-Ubuntu SMP Mon Jul 6 21:33:03 UTC 2015 x86_64
Optional features available: CPU affinity setting, IPv6 flow label, TCP congestion algorithm setting, sendfile / zerocopy

[ ~]$ bin/iperf3 -v
iperf 3.1.3
Linux <psc.host> 2.6.32-504.1.3.el6.netboot #5 SMP Wed Nov 26 23:52:30 EST 2014 x86_64
Optional features available: CPU affinity setting, IPv6 flow label, TCP congestion algorithm setting, sendfile / zerocopy

Command lines------------------------------------------
Sender:
    iperf3 -c <remote host IP> -u -b20m -i2 -t300

Receiver:
    iperf3 -s -i1

Questions----------------------------------------------------

I would like to know what the "OUT OF ORDER" lines are telling me.

What is "incoming packet" relative to "received packet"?

What does "SP = 5" mean?

Does every "out-of-order" packet detected also cause the "lost" packet counter to increment?

Here is  a short sample of output on the receiver:

(Full output at:
https://docs.google.com/document/d/1eO4BixVYuNHGY4MAYtZlGkNHDk-NyNyI5NZ5-J0yeHI/edit?usp=sharing )

[ ~]$ bin/iperf3 -s -i2

-----------------------------------------------------------

Server listening on 5201

-----------------------------------------------------------

Accepted connection from <remote host IP>, port 41679

[  5] local <psc host IP> port 5201 connected to <remote host IP> port 54629

[ ID] Interval           Transfer     Bandwidth       Jitter    Lost/Total Datagrams

[  5]   0.00-2.00   sec  4.54 MBytes  19.0 Mbits/sec  0.237 ms  0/581 (0%)

[  5]   2.00-4.00   sec  4.77 MBytes  20.0 Mbits/sec  0.202 ms  0/610 (0%)

iperf3: OUT OF ORDER - incoming packet = 1582 and received packet = 1588 AND SP = 5

[  5]   4.00-6.00   sec  4.76 MBytes  20.0 Mbits/sec  0.202 ms  3/611 (0.49%)

[  5]   6.00-8.00   sec  4.77 MBytes  20.0 Mbits/sec  0.179 ms  0/610 (0%)

[  5]   8.00-10.00  sec  4.77 MBytes  20.0 Mbits/sec  0.225 ms  0/610 (0%)

[  5]  10.00-12.00  sec  4.77 MBytes  20.0 Mbits/sec  0.195 ms  0/611 (0%)

iperf3: OUT OF ORDER - incoming packet = 3807 and received packet = 3812 AND SP = 5

iperf3: OUT OF ORDER - incoming packet = 4118 and received packet = 4119 AND SP = 5

[  5]  12.00-14.00  sec  4.77 MBytes  20.0 Mbits/sec  0.218 ms  2/610 (0.33%)

[  5]  14.00-16.00  sec  4.77 MBytes  20.0 Mbits/sec  0.180 ms  0/610 (0%)

[  5]  16.00-18.00  sec  4.79 MBytes  20.1 Mbits/sec  0.259 ms  0/613 (0%)

[  5]  18.00-20.00  sec  4.75 MBytes  19.9 Mbits/sec  0.187 ms  0/608 (0%)

iperf3: OUT OF ORDER - incoming packet = 6501 and received packet = 6502 AND SP = 5

[  5]  20.00-22.00  sec  4.77 MBytes  20.0 Mbits/sec  0.273 ms  1/610 (0.16%)

[  5]  22.00-24.00  sec  4.77 MBytes  20.0 Mbits/sec  0.167 ms  0/611 (0%)

[  5]  24.00-26.00  sec  4.77 MBytes  20.0 Mbits/sec  0.206 ms  0/610 (0%)

[  5]  26.00-28.00  sec  4.79 MBytes  20.1 Mbits/sec  0.284 ms  0/613 (0%)

[  5]  28.00-30.00  sec  4.75 MBytes  19.9 Mbits/sec  0.166 ms  0/608 (0%)

[  5]  30.00-32.00  sec  4.77 MBytes  20.0 Mbits/sec  0.189 ms  0/610 (0%)

--

Brian Tierney, http://www.es.net/tierney
Energy Sciences Network (ESnet), Berkeley National Lab
http://fasterdata.es.net