Setting the protocol

Red Hat Enterprise Linux 9.2 LPAR mode z/VM guest

Use the protocol attribute to set the protocol.

Before you begin

The device must be offline while you set the protocol.

About this task

The type of interface depends on the protocol. Protocol 4 results in MPC interfaces with interface names mpc<n>. Protocols 0, 1, or 3 result in CTC interfaces with interface names of the form ctc<n>.

To choose a protocol, set the protocol attribute to one of the following values:

0: This protocol provides compatibility with peers other than z/OS®, for example, a z/VM® TCP service machine. This value is the default.
1: This protocol provides enhanced package checking for Linux® peers.
3: This protocol provides for compatibility with z/OS peers.
4: This protocol provides for MPC connections to VTAM® on traditional mainframe operating systems.

Procedure

Issue a command of this form:

# echo <value> > /sys/bus/ccwgroup/drivers/ctcm/<device_bus_id>/protocol

Example

In this example, the protocol is set for a CTCM group device 0.0.2000:

# echo 4 > /sys/bus/ccwgroup/drivers/ctcm/0.0.2000/protocol