NIC Enumeration in XenServer Dell Edition

NIC enumeration, i.e. mapping of physical network interface to ethX device name, in XenServer Dell Edition is based on the device position in the server. The integrated LAN on Motherboard (LOM) ports are always enumerated first in order of their physical marked position: GB1, GB2, etc. The add-in network cards are enumerated after the LOM ports in ascending order of slot position and PCI bus/device/function information.

For example, if in a server there are 2 LOM ports and one dual port network adapter in PCI slot 4, the NIC enumeration will be as follows: eth0: LOM Port 1 (Gb1); eth1: LOM Port 2 (Gb2), eth2 and eth3: ports on adapter in Slot 4 (arranged in ascending bus/device/function number)

The NIC enumeration and corresponding position in the server can be found by logging in to XenServer local console shell and issuing the following command:
# biosdevname -d

The output of the command should be similar to one below:

BIOS device: eth0
Kernel name: eth0
Permanant MAC: 00:1E:4F:1F:77:67
Assigned MAC : 00:1E:4F:1F:77:67
Driver: bnx2 Driver version: 1.6.7b
Firmware version: 3.5.12 UMP 1.1.8
Bus Info: 0000:03:00.0
PCI name : 0000:03:00.0
PCI Slot : embedded
SMBIOS Device Type: Ethernet
SMBIOS Instance: 1
SMBIOS Enabled: True

BIOS device: eth1
Kernel name: eth1
Permanant MAC: 00:1E:4F:1F:77:69
Assigned MAC : 00:1E:4F:1F:77:69
Driver: bnx2
Driver version: 1.6.7b
Firmware version: 3.5.12 UMP 1.1.8
Bus Info: 0000:07:00.0
PCI name : 0000:07:00.0
PCI Slot : embedded
SMBIOS Device Type: Ethernet
SMBIOS Instance: 2
SMBIOS Enabled: True

BIOS device: eth2
Kernel name: eth2
Permanant MAC: 00:15:17:24:A4:B0
Assigned MAC : 00:15:17:24:A4:B0
Driver: e1000
Driver version: 7.6.9.2-NAPI
Firmware version: 5.6-2
Bus Info: 0000:0b:00.0
PCI name : 0000:0b:00.0
PCI Slot : 4

BIOS device: eth3
Kernel name: eth3
Permanant MAC: 00:15:17:24:A4:B1
Assigned MAC : 00:15:17:24:A4:B1
Driver: e1000
Driver version: 7.6.9.2-NAPI
Firmware version: 5.6-2
Bus Info: 0000:0b:00.1
PCI name : 0000:0b:00.1
PCI Slot : 4

The BIOS device name is the name suggested by system BIOS and is used by XenServer kernel to enumerate the device name. As shown in above output, the PCI Slot and SMBIOS instance fields for eth0 and eth1 show that these devices are two LOM NIC ports on the server. Fields PCI Slot filed for eth2 and eth3 shows that these devices are two ports on a dual port network adapter present in PCI slot number 4. The BIOS device name filed should match the Kernel name field. In rare cases, after the XenServer boots for the first time, the BIOS device name may not match the kernel device name. To resolve this issue, log in to XenServer local console shell and restart xapi service using the following command:
# service xapi restart


References:

biosdevname utility: http://linux.dell.com/biosdevname/