From Fedora Project Wiki
Consistent network device naming
Fedora 18 continues previous releases' use of biosdevname to set network device names in a deterministic manner. Ethernet ports embedded on server motherboards will be named em<port_number>
, while ports on PCI cards will be named p<slot_number>p<port_number>
, corresponding to the chassis labels. This feature may be disabled by passing "biosdevname=0"
on the kernel command line, in which case, behavior will revert to using ethX names.