qeth device driver for OSA-Express (QDIO) and HiperSockets
The qeth device driver supports a multitude of network
connections, for example, connections through Open Systems Adapters
(OSA), HiperSockets,
guest LANs, and virtual switches.
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 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. Figure 1. OSA-Express adapters are real LAN-adapter
hardware
The qeth device driver supports OSA-Express
features for the IBM Z mainframes that are relevant to Red Hat® Enterprise Linux®
8.6 as shown in Table 1:
Table 1. The qeth device driver support for OSA-Express features
Note: Unless
otherwise indicated, OSA-Express refers to the OSA-Express
features as shown in Table 1.
The qeth device driver supports CHPIDs of type OSD 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.
OSX
Supported up to z14, 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.
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/VMguest virtual machines. 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-Express in layer 3 mode
Simulated HiperSockets (layer 3) mode
Simulated Ethernet 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.Figure 2. Guest LAN
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. Figure 3. Virtual
switch
A dedicated OSA adapter can be an option, but is not required for 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.Figure 4. HiperSockets bridge port in z/VM
From a Linux point of view there is no difference
between guest LAN- and VSWITCH-devices; thus Linux talks
about guest LAN-devices independently of their z/VM-attachment
to a guest LAN or VSWITCH.
For information about guest LANs, virtual switches, and
virtual HiperSockets, as well as about
attaching OSD or HiperSockets to z/VM guests directly, see z/VM:
Connectivity, SC24-6267.
The qeth device driver supports OSA-Express features for the IBM Z mainframes that are relevant to Red Hat® Enterprise Linux® 8.6 as shown in Table 1:
