Strange ping behaviour

[cojuer]

Hello,
I've encountered strange behaviour of ping while using dilated emulation.

My installation steps(got no errors during installation):

• installed 14.04 Ubuntu on Virtualbox
• ran 'install.sh both' for commit 00fe8da (on last commit I have problems with iperf3 hanging virtual machine)
• installed Mininet with

sudo make clean
sudo make install

• installed openvswitch using apt

Following simple topology was used:
Host1 - TCLink1 - Switch - TCLink2 - Host2

I tested ping from Host1 to Host2 using Mininet CLI.
No delays, TDF=2, I'm getting mostly normal values:

64 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=0.902 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=64 time=999 ms
64 bytes from 10.0.0.2: icmp_seq=3 ttl=64 time=0.012 ms
64 bytes from 10.0.0.2: icmp_seq=4 ttl=64 time=2997 ms
64 bytes from 10.0.0.2: icmp_seq=5 ttl=64 time=0.012 ms
64 bytes from 10.0.0.2: icmp_seq=6 ttl=64 time=0.012 ms
64 bytes from 10.0.0.2: icmp_seq=7 ttl=64 time=0.012 ms
64 bytes from 10.0.0.2: icmp_seq=8 ttl=64 time=0.013 ms
64 bytes from 10.0.0.2: icmp_seq=9 ttl=64 time=0.012 ms
64 bytes from 10.0.0.2: icmp_seq=10 ttl=64 time=0.012 ms

1us on TCLink1, TDF=2, most of the values are incorrect:

64 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=0.687 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=64 time=999 ms
64 bytes from 10.0.0.2: icmp_seq=3 ttl=64 time=1999 ms
64 bytes from 10.0.0.2: icmp_seq=4 ttl=64 time=2999 ms
64 bytes from 10.0.0.2: icmp_seq=5 ttl=64 time=3996 ms

10ms on TCLink1, TDF=2:

64 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=21.7 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=64 time=1021 ms
64 bytes from 10.0.0.2: icmp_seq=3 ttl=64 time=2018 ms
64 bytes from 10.0.0.2: icmp_seq=4 ttl=64 time=3018 ms
64 bytes from 10.0.0.2: icmp_seq=5 ttl=64 time=4017 ms

Also tested for a138c42 commit with 1us on TCLink1 and TDF=4:

64 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=1.30 ms
64 bytes from 10.0.0.2: icmp_seq=2 ttl=64 time=2997 ms
64 bytes from 10.0.0.2: icmp_seq=3 ttl=64 time=5997 ms
64 bytes from 10.0.0.2: icmp_seq=4 ttl=64 time=0.012 ms
64 bytes from 10.0.0.2: icmp_seq=5 ttl=64 time=11988 ms

Looks as if every next ping shows (seq - 1) * 999 * (TDF-1) + rtt time with some exceptions and it somehow depends on delays.

Best regard,
Thank you.