What you should know about IUCV

6.10 z/VM guest

The NETIUCV device driver assigns IUCV interface names and creates IUCV devices in sysfs.

IUCV direct and routed connections

The NETIUCV device driver uses TCP/IP over z/VM® virtual communications.

The communication peer is a guest of the same z/VM or the z/VM control program. No subchannels are involved, see Figure 1.

Figure 1. Direct IUCV connection
This graphic shows a network interface that maps to an IUCV device and is connected to a communication peer within z/VM.

If your IUCV connection is to a router, the peer can be remote and connected through an external network, see Figure 2.

Figure 2. Routed IUCV connection
In this graphic the IUCV device is connected to a router or TCP/IP service machine which is connected to a network adapter and an external network.

The standard definitions in the z/VM TCP/IP configuration files apply.

For more information of the z/VM TCP/IP configuration see: z/VM: TCP/IP Planning and Customization, SC24-6331.

IUCV interfaces and devices

The NETIUCV device driver assigns names to its devices.

The NETIUCV device driver uses the base name iucv<n> for its interfaces. When the first IUCV interface is created (see Creating an IUCV device) it is assigned the name iucv0, the second is assigned iucv1, the third iucv2, and so on.

For each interface, a corresponding IUCV device is created in sysfs at /sys/bus/iucv/devices/netiucv<n> where <n> is the same index number that also identifies the corresponding interface.

For example, interface iucv0 corresponds to device name netiucv0, iucv1 corresponds to netiucv1, iucv2 corresponds to netiucv2, and so on.