Network fails, when no HDMI Monitor is connected

Preface:
The described failure only happens, when no activated HDMI Monitor is plugged into the Jetson board. OS is Jetson TK1 R21.2 - December 2014.

I’m struggling with network problems when down/uploading files via apt-get or wget or scp.
The network dies completly (ssh/telnet tunnel broken).
If I connect a Monitor after the failure, login locally and check the network connection, i can’t even ping google.com or 8.8.8.8. A manual network restart does not fix the problem, either.

The weird part is, that if I plug in the Monitor in the first place and start any network data transfer after that via ssh login, no network failure happens at all.

Does anyone have similiar problems running a headless jetson board or is my jetson board maybe simply broken?

It is probable (not guaranteed) that this is a known issue of the R21.x gigabit. You’ll see some threads on gigabit workarounds such as using mii-tool to set the interface to 100 Mbit. R19.x does not have this issue as it’s kernel seems to be from prior to the issue. I believe (if the issue is the known R21.x gigabit issue) that the problem is due to an interaction between scheduler and NIC driver.