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Consistent Network Device Naming

Fedora 16 provides consistent network device naming for network interfaces. This feature changes the name of network interfaces on a system in order to make locating and differentiating the interfaces easier.
Traditionally, network interfaces in Linux are enumerated as eth[0123…], but these names do not necessarily correspond to actual labels on the chassis. Modern server platforms with multiple network adapters can encounter non-deterministic and counter-intuitive naming of these interfaces. This affects both network adapters embedded on the motherboard (Lan-on-Motherboard, or LOM) and add-in (single and multiport) adapters.
The new naming convention assigns names to network interfaces based on their physical location, whether embedded or in PCI slots. By converting to this naming convention, system administrators will no longer have to guess at the physical location of a network port, or modify each system to rename them into some consistent order.
This feature, implemented via the biosdevname program, will change the name of all embedded network interfaces, PCI card network interfaces, and virtual function network interfaces from the existing eth[0123…] to the new naming convention as shown in Table A.1, “The new naming convention”.
Table A.1. The new naming convention
Device Old Name New Name
Embedded network interface (LOM) eth[0123…] em[1234…][a]
PCI card network interface eth[0123…] p<slot>p<ethernet port>[b]
Virtual function eth[0123…] p<slot>p<ethernet port>_<virtual interface>[c]
[a] New enumeration starts at 1.
[b] For example: p3p4
[c] For example: p3p4_1

System administrators may continue to write rules in /etc/udev/rules.d/70-persistent-net.rules to change the device names to anything desired; those will take precedence over this physical location naming convention.

A.1. Affected Systems

Consistent network device naming is enabled by default for all systems that meet the requirements in Section A.2, “System Requirements”.
Regardless of the type of system, Fedora guests will not have devices renamed unless the virtual machine BIOS provides the SMBIOS information outlined in Section A.2, “System Requirements”. Also, upgrades from prior releases that did not use this naming convention (that is, Fedora 14 and older) are unaffected, and the old naming convention will continue to be used.