Comment # 12 on bug 819514 from Erik Martre

I suspect it to be a very old bug, getting up again from the grave it had been
burried in. The one you have to remove and reload r8169 module to make ethernet
connection working again - that's what I do :

sudo modprobe -r r8169
sudo modprobe r8169

and it's OK. 

>From what I found on various forums it could be related to ethernet card
(Realtek PCIe GBE Family Controller, the driver of which on Realtek site is 
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller - I didn't try to
replace Tumbleweed's driver with this one). After a certain amount of sleeping
time, the card enters deep sleep mode and won't wake up again. Booting on other
OS (W10 in my case) won't wake it up, you'll get a network error ("unidentified
network "or smthg like that) and you'll have to run the command "netsh winsock
reset" as administrator and reboot your machine.

I'll add that I made a fresh install of Tumbleweed (suspecting somme corrupted
files in my previous Leap 42.3 that I had upgraded), and before packages
updating this problem was not present, that's what made me think of a
regression.