qeth device driver for OSA-Express (QDIO) and HiperSockets

Real connections that use OSA-Express

An IBM® mainframe uses OSA-Express adapters, which are real LAN-adapter hardware, see Figure 1. These adapters provide connections to the outside world, but can also connect virtual systems (between LPARs or between z/VM® guest virtual machines) within the mainframe. The qeth driver supports these adapters if they are defined to run in queued direct I/O (QDIO) mode (defined as OSD, OSM, or OSX in the hardware configuration). OSD-devices are the standard IBM Z® LAN-adapters. For details about OSA-Express in QDIO mode, see Open Systems Adapter-Express Customer's Guide and Reference, SA22-7935.

The qeth device driver supports CHPIDs of type OSD, OSM, and OSX:

OSD

provides connectivity as the standard IBM Z LAN adapter type, running in either layer 3 or layer 2 mode. When running in layer 3 mode, only IP traffic is supported, using IP addresses. When running in layer 2 mode, the traffic is protocol-independent, using MAC addresses.

OSM

provides connectivity to the intranode management network (INMN) from Unified Resource Manager functions to a zEnterprise® CPC. OSM is also used for machines in DPM mode.

OSX

provides connectivity to and access control for the intraensemble data network (IEDN), which is managed by Unified Resource Manager functions. A zEnterprise CPC and zBX within an ensemble are connected through the IEDN. See zEnterprise System Introduction to Ensembles, GC27-2609 and zEnterprise System Ensemble Planning and Configuring Guide, GC27-2608 for more details.

OSX connectivity is unavailable as of z15®.

HiperSockets

An IBM mainframe uses internal connections that are called HiperSockets. These simulate QDIO network adapters and provide high-speed TCP/IP communication for operating system instances within and across LPARs. For details about HiperSockets, see HiperSockets Implementation Guide, SG24-6816.

HiperSockets Converged Interface (HSCI)

With HSCI, you can integrate HiperSockets connectivity with your external LAN, thus creating a single logical network interface. The single interface simplifies network management.

Virtual connections for Linux® on z/VM

z/VM offers virtualized LAN-adapters that enable connections between z/VM guest virtual machines and the outside world. It allows definitions of simulated network interface cards (NICs) attached to certain z/VM guests. The NICs can be connected to a simulated LAN segment called guest LAN for z/VM internal communication between z/VM guest virtual machines, or they can be connected to a virtual switch called VSWITCH for external LAN connectivity.

Guest LAN

Guest LANs represent a simulated LAN segment that can be connected to simulated network interface cards. There are three types of guest LANs:

• Simulated OSA in layer 3 mode
• Simulated HiperSockets (layer 3) mode
• Simulated OSA in layer 2 mode

Each guest LAN is isolated from other guest LANs on the same system (unless some member of one LAN group acts as a router to other groups). See Figure 2.

Virtual switch

A virtual switch (VSWITCH) is a special-purpose guest LAN that provides external LAN connectivity through an additional OSA-Express device served by z/VM without the need for a routing virtual machine, see Figure 3.

A dedicated OSA adapter can be an option, but is not required for a VSWITCH.

The qeth device driver distinguishes between virtual NICs in QDIO mode or HiperSockets mode. It cannot detect whether the virtual network is a guest LAN or a VSWITCH.

HiperSockets bridge port

A HiperSockets bridge port connects a network defined by a virtual switch to a HiperSockets LAN. The two networks are combined into one logical network. If the VSWITCH is connected to an external Ethernet LAN, the HiperSockets LAN can then communicate outside the CEC as shown in Figure 4. You can thus connect a HiperSockets LAN to an external LAN without using a router.

Linux can use a bridge port, for example, to connect an OSA or HiperSockets port to a Linux bridge. For more information, see Layer 2 promiscuous mode.

For information about guest LANs, virtual switches, HiperSockets bridge ports, virtual HiperSockets, and z/VM guests that are directly attached to OSD or HiperSockets, see z/VM: Connectivity, SC24-6267.

The qeth network device driver supports HiperSockets on all supported IBM Z hardware systems. For supported OSA-Express features, see Table 1 and Table 2.