I have two CentOS servers connected via a 10 Gb fiber optic cable with a network emulator connected between them. All three units sit on a desk in the lab. There is also a regular 1 Gbit Ethernet cable connected to each of the machines, which provide internet connectivity.

When I set the latency to something roughly below 30 ms, all is fine. When the latency gets to 70ms and above, and definitely 130ms, the network layer suspends.

For instance, if I set the latency (delay) to 70ms, then launching TeamViewer (or any other application that uses network connectivity) never happens or does not work. There is no timeout message, simply no response. I have to lower to latency back down to zero to see any response and have the box start working.

What is the problem and how would I go about fixing it?

It seems to me some sort of setting in Linux causes one of the CentOS networking drivers to sit in an infinite loop or something.

eth0 is the connection to the internet, all settings are default

eth2 is the 10 Gbit fiber optic connection to the other computer with the MTU set to 9600 with all other parameters at default values.

  • I'd look at the kernel log and run a packet capture to attempt to diagnose the problem. Also, start with simple network traffic like 'ping'. – Mark Wagner Nov 4 '13 at 23:38
  • I use ping, so I am surprised that I did not think of trying to see what ping does instead of my network communication software and TeamViewer. – Sarah Weinberger Nov 5 '13 at 0:13
  • Ping also failed. I am glad that I tried that, so we shall see. – Sarah Weinberger Nov 5 '13 at 4:28

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