How to restart one ethernet port?

No, i have only issue reported in this thread:

The issue is happening on different ports. Actually on all 4 of them. The one I am experecing the 'stuck' port the most is the one with Raspberry Pi device which i restart the most. This way the port of that deivce gets stuck the most. But of course i had replaced the for tests at the very begginig when i notices the problem. That did not resolve the problem.