Defining APPC connections

An APPC connection consists of one or more sets of sessions. The sessions in each set have identical characteristics, apart from being either contention winners or contention losers.

Each set of sessions can be assigned a modename that enables it to be mapped to a z/OS® Communications Server logmode name and from there to a class of service (COS). A set of APPC sessions is therefore referred to as a modeset.

An APPC terminal is often an APPC system that supports only a single session and which does not support an LU services manager. There are several ways of defining such terminals; further details are given under Defining single-session APPC terminals. This section describes the definition of one or more modesets containing more than one session.

To define an APPC connection to a remote system, you must create the following resources:
  1. A CONNECTION resource to define the remote system.
  2. A SESSIONS resource to define each set of sessions to the remote system.

However, you must not have more than one APPC connection installed at the same time between an LU-LU pair. Nor should you have an APPC and an LUTYPE6.1 connection installed at the same time between an LU-LU pair.

For all APPC connections, except single-session connections to APPC terminals, CICS® automatically builds a set of special sessions for the exclusive use of the LU services manager, using the modename SNASVCMG. This is a reserved name, and cannot be used for any of the sets that you define.

If you are defining a z/OS Communications Server logon mode table, remember to include an entry for the SNASVCMG sessions. See ACF/SNA LOGMODE table entries for CICS.