I have a system with two ethernet sockets on the motherboard - and it took me quite a while to fathom out how to get the system networking stable after a clean arch install a couple of weeks ago (with the new network naming scheme) from the February archiso files.
It turned out that the two network interfaces were called "eno1" and "etho" when the system assigned the names - which I found odd with one being the new naming scheme and the other the old scheme! - but decided that since eno1 was in the new network naming scheme that I would set up for fixed IP address with the eno1 interface. Initially I used igplugd/netcfg but at random the network would fail to be available after the system booted up - having seen some reports of problems with ifplugd/netcfg I decided to install NetworkManager and set up the fixed ip address for interface eno1 that way instead. However it still kept booting with random occasions where the network failed to come alive. This frustrated me somewhat until I eventually came across the wiki entry about problems with dual NICs not being assigned the same way during boot in the section under "udev". I also noticed that the second interface sometimes was called eth0 and sometimes eth1! There was always an interface called eno1 however. What I now think is that the hardware MAC address for the two NICs were being assigned to the network names at random - so I followed the "fix" suggested at https://wiki.archlinux.org/index.php/Ud … ork_device and assigned eno1 to the MAC address of the socket I knew I was plugged into, and secondly assigned eno2 to the other one.
Since doing that the network has come alive every time after booting, and I have had no problems whatsoever with networking since then - so I guess it might be useful to add this advice to the network setup wiki page at https://wiki.archlinux.org/index.php/Ne … figuration since it was not obvious that I should look at the udev page for advice about it!
Anyway I thought I would post this on the forum here in case others have had issues with network setup where inconsistent behaviour has been seen for random network failure at bootup.