In RHEL 6.1 the default names assigned to Dell server network interfaces changed from ethX to emX and pXpX. The new names describe where a network interface physically resides in the system, and will have the following format:
emX – the X (first, second, etc.) onboard interface
pXpY – PCI device X port Y
Dell wrote a really good white paper on this, and the following text from the document summarizes how the pieces fit together:
“A naming mechanism that can impart meaning to the network interface‟s name based on the physical location of a network port in concordance to the intended system design is necessary. To achieve that, the system firmware has the ability to communicate the intended order for network devices on the mother board to the Operating System via standard mechanisms such as SMBIOS and ACPI.
The new naming scheme uses ‘biosdevname’ udev helper utility , developed by Dell and released under GPL, suggests new names based on the location of the network adapters on the system as suggested by system BIOS.”
I like the new format, and this will definitely be a nice addition to hardware provisioning systems. Hopefully in the near future we won’t have to poke around with lspci to see which interface is which. :)