TLP will power off devices during suspend to save battery life. This answer: Need to reconnect ethernet cable to get it work after docking laptop into dock station. will reload the R8169 drivers for you realtek network card and might be a sufficient approach.
Another approach is to leave power to the network card during suspend. To do this use sudo -H gedit /etc/default/tlp and insert these lines:
USB_BLACKLIST="10ec:8168"
USB_BLACKLIST="103c:832b"
Save the file and reboot.
