CONNECTION resource definition for EXCI

The EXCI option is provided on the PROTOCOL attribute of the CONNECTION resource definition to indicate that the connection is for use by an MVS™ program using the external CICS® interface.

The CONNTYPE attribute is provided on the CONNECTION resource definition. For EXCI connections, this indicates whether the connection is generic or specific. It is not to be used for any protocol other than the external CICS interface.

The following parameters are relevant to EXCI:

For external CICS interface connections, indicates the nature of the connection.
The connection is for communication from a non-CICS client program to the CICS region, and is specific. A specific connection is an MRO link with one or more sessions dedicated to a single user in a client program.
Note: A user is a program that has issued an Initialize_User request (or for which an Initialize_User request has been issued), with a unique name per TCB. For example:
  • A simple client program running under MVS can be a single user of the external CICS interface.
  • A client program running under MVS can open several pipes and issue external CICS interface calls over them sequentially, on behalf of different vendor packages. In this case, from the viewpoint of the client program, each of the packages is a user, identified by a unique user name. Thus a single client program can operate on behalf of multiple users.
  • A program running under MVS can attach several TCBs, under each of which a vendor package issues external CICS interface calls on its own behalf. Each package is a client program in its own right, and runs under its own TCB. Each is also a user, with a unique user name.

For a specific connection, NETNAME is mandatory.

The connection is for communication from a non-CICS client program to the CICS system, and is generic. A generic connection is an MRO link with a number of sessions to be shared by multiple EXCI users. For a generic connection you cannot specify the NETNAME attribute.
Note: You must install only one generic EXCI connection in a CICS region.
For an external CICS interface connection, NETNAME corresponds to the name of the user of a specific pipe, as specified on the user_name parameter of an INITIALISE_USER call.

For an external CICS interface specific pipe, you must specify a NETNAME.

For external CICS interface generic pipes, you must leave NETNAME blank.

The type of protocol that is to be used for the link.
For MRO between CICS regions. You must leave the PROTOCOL blank for MRO, and on the SESSIONS definition you must specify LU6.1 as the PROTOCOL.
APPC (LUTYPE6.2 protocol)
Advanced program-to-program communication, or APPC protocol. This is the default value for ACCESSMETHOD(VTAM®). Specify this for CICS-CICS ISC.
Note: VTAM is now the z/OS® Communications Server.
LUTYPE6.1 protocol. Specify this for CICS-CICS ISC or CICS-IMS ISC, but not for MRO.
The external CICS interface. Specify this to indicate that this connection is for use by a non-CICS client program using the external CICS interface.

If you specify PROTOCOL(EXCI), you must also specify ACCESSMETHOD(IRC). EXCI is implemented in MRO using the CICS interregion communication program, DFHIRP, and cannot use MRO links that use MVS cross-memory services (XM). EXCI can use also XCF MRO links, which also work through DFHIRP.