PCI network adapter limitations

This chapter lists limitations of RoCE Express® and considerations of Network Express.

RoCE Express limitations

Promiscuous mode: Linux® instances do not have access to the physical functions of RoCE Express. As a consequence, capabilities that require a physical function are not available. In particular, you cannot run network interfaces of PCI functions in promiscuous mode.
z/VM® VSWITCH support: You cannot add network interfaces of PCI functions to a z/VM VSWITCH.
VEPA mode: Virtual Edge Port Aggregator (VEPA) enables to send all outgoing traffic to an adjacent network switch instead of using the virtual switch inside the PCI network adapter. To enable this feature, you require access to the adapter's physical functions. Consequently, RoCE Express functions cannot be set to VEPA mode.
z/OS® connectivity: z/OS cannot use RoCE Express for TCP/IP connections, see also z/OS connectivity.

Promiscuous mode: By configuring FIDPARM, Network Express NETH functions can run in promiscuous mode. For more information about promiscuous mode, see the topic on configuring FIDPARM in the networking part of the Device Drivers (FIDPARM and promiscuous mode).
z/VM VSWITCH support: You can attach PCI functions through OSA-Express or OSH of Network Express in hybrid mode for z/VM VSWITCH interfaces to appear as channel based network devices (type OSD) in Linux z/VM guests.
VEPA mode: While NETH functions cannot be set to VEPA mode, you can configure NETD physcial functions (PFs) to set the port and all attached NETD virtual functions (VFs) to VEPA mode.
z/OS connectivity: You can use OSH of Network Express in hybrid mode for TCP/IP connections.