PowerEdge: Enhanced Systemd naming scheme in RHEL 8

In Red Hat Enterprise Linux 6 and 7, biosdevname was the default naming scheme for the network interfaces on supported Dell systems.

From RHEL 8 onwards systemd naming is the default naming scheme for the network interfaces on supported Dell systems.

Systemd naming is enhanced with the below features to improve the naming for the network interfaces.  

Enhanced systemd network naming to look at parent devices when searching for PCI slots:

• In the older versions systemd does not traverse the PCI tree to look for parent devices when looking for the PCI slot information. The PCI slot information may be available for only the PCI function 0 in a multi function device.  
• After the enhancements, systemd now looks for parent devices while retrieving PCI slot information.
• Even if a PCIe network controller device does not have an associated slot number but one of its parents does, systemd traverses the PCI tree to get the PCI slot information from its parents.
   

Network interface naming for the network card installed in PCIe slot 2:

Enhanced systemd network naming to improve SR-IOV device naming:

• When a SRIOV Virtual Function (VF) is created, the kernel exposes physfn/virtfnX links in sysfs. In the older versions, systemd does not look at those physfn/virtfnX links in sysfs that the kernel exposes.
• Now with the enhancements systemd looks at physfn/virtfnX links in sysfs when a VF is created.
• Previously SR-IOV virtual devices were named as if independent but now these virtual devices are now named based on the name of the parent interface, with a suffix of "v<N>," where <N> is the virtual device number.

Network interface naming after creating two SRIOV VFs for the network card installed in PCIe slot 2:

Network interface naming after creating two SRIOV VFs for the onboard embedded network card:

Enhanced systemd network naming to interpret ARI to improve NPAR-EP device naming:

• Network partitioning (NPAR) functionality provides the ability to create eight NIC partitions and NPAR-EP (Extended Partitions) provides ability to create eight extra partitions (total 16). NPAR-EP requires PCI ARI enabled. In the older versions, systemd does not interpret ARI.
• For more information about ARI, see https://pcisig.com/sites/default/files/specification_documents/ECN-alt-rid-interpretation-070604.pdf
• An ARI Device interprets its directly associated IDs (Routing, Requester, and Completer) as having an 8-bit Function Number instead of the traditional 3-bit Function Number.
• Now with the enhancements systemd use the 8-bit function numbers when ARI is enabled to improve naming for NPAR-EP partitions.

Network interface naming after enabling NPAR-EP for the network card: