Network adapters as of IBM z17 and IBM LinuxONE 5
You can use the network adapters Network Express Adapter and IBM Integrated Network Adapter 100G (IBM INA 100G) for Ethernet and RoCE networking as of IBM® z17 ™ and IBM LinuxONE 5.
In this chapter, the term network adapters refers to Network Express adapters and the IBM Integrated Network Adapter 100G (IBM INA 100G), unless stated otherwise.
Features of the network adapters
The network adapters have two physical ports with one physical channel ID (PCHID) per port, and hence two PCHIDs per adapter.
The network adapters are single root I/O virtualization (SR-IOV) capable devices, see Single Root Input/Output Virtualization (SR‑IOV).
The IBM Integrated Network Adapter 100G provides 100 Gb Ethernet connectivity through two QSFP28 optical modules. The adapter plugs into the PCIe connectors in the CPC drawers.
The Network Express Adapter provides 10 GB and 25 GB Ethernet connectivity.
- Hybrid mode (function type NETH). Hybrid mode also supports CCW devices of type OSH, but these are not supported on Linux.
- Direct mode (function type NETD).
The IBM INA 100G operates in NETD mode only.
Single Root Input/Output Virtualization (SR‑IOV)
Single Root Input/Output Virtualization (SR-IOV) is a PCI Express (PCIe) specification that allows a single physical adapter to present multiple virtual functions (VFs). Each VF can be assigned to a separate operating system instance. The operating system instance has direct access to the VF. The physical function (PF) represents the full-function device and provides control and management of the adapter, including the configuration of VFs and access to advanced hardware capabilities.
SR-IOV on IBM Z and IBM LinuxONE
On IBM Z and IBM LinuxONE systems, SR-IOV capable adapters provide one PF per port and multiple VFs. The role of the PF depends on the adapter type and configuration mode.
For example, for adapters in NETH mode, the PF is owned by firmware, and Linux instances use only VFs. For adapters that support the PCI functon type NETD, when operating in NETD mode (direct mode), the PF must be assigned to a partition. In this case, the partition controls the corresponding adapter port.
In NETD, both PFs and VFs must be defined in the I/O configuration, and VFs are instantiated and managed through the PF. Linux on IBM Z and LinuxONE typically uses VFs to achieve near-native I/O performance while maintaining clear separation between partitions.