I want to do some network measurements. ... / 2012-09-05

2012-09-05 I want to do some network measurements. ...
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I want to do some network measurements. Measuring throughput over tcp or udp is easy: use iperf. Although the iperf server process in daemon mode was using 100% cpu for each(!) measurement somehow, so the load on the machine tested ran up to more than 50.

But I am also interested in tcp setup time. It took a bit longer to find something which does that. Searching gave me measure tcp connection setup time: time-gai-connect which was developed to measure differences in IPv4 and IPv6 tcp connection setup times. Interesting answers:
$ ./time-gai-connect.py www.google.com
2a00:1450:400c:c05::63                   19.62209 ms                           19.78207 ms                           20.66183 ms                           19.69004 ms                           20.01190 ms                            20.47896 ms                           21.71206 ms
And this one is really strange to me... on the machine which runs both the IPv4 address and IPv6 address for idefix.net:
$ ./time-gai-connect.py idefix.net
2001:980:14ca:42::18                      0.35095 ms                             0.18501 ms
Yes, the IPv6 tcp connect setup takes longer with IPv6 on this local connection.

I added code to measure resolving time when testing it on my laptop, which now shows shorter times for IPv6 than IPv4, one wireless hop away from the same system.

$ ./time-gai-connect.py idefix.net
Resolving                                 3.20196 ms
2001:980:14ca:42::18                      0.96989 ms                             1.49107 ms
Measuring this gives more new questions than answers... it seems remote destinations are faster for IPv6 than for IPv4. Example from the same laptop:
$ ./time-gai-connect.py www.xs4all.nl
Resolving                                34.10101 ms
2001:888:0:18::80                        15.76281 ms                             15.84506 ms
And from the system running idefix.net:
$ ./time-gai-connect.py www.xs4all.nl
Resolving                                 2.60282 ms
2001:888:0:18::80                        14.32490 ms                             15.16104 ms

But anyway, iperf and time-gai-connect will give me the answers I want to measure.

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IPv6 check

Running test...
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