### Configuring CICS for APPC communications

This section describes configuring CICS for Remote Debug APPC sessions. Assuming that administrators will configure Remote Debug APPC sessions at both APPC/MVS and CICS, some important differences should be noted. CICS interfaces directly with VTAM (that is, it runs as a VTAM application). For that reason, the APPC/MVS subsystem is not used for CICS APPC sessions. Instead, APPC/MVS-like functions are performed by the CICS region. When configuring for Remote Debug, this is evident while defining CPI-C side information, which is done using CICS system transactions as opposed to using the APPC/MVS facilities that were defined previously. Also, since CICS is a VTAM application, it is assumed that you already have an APPL major node which serves as the LU for APPC sessions. That is, CICS uses its own APPL and not the one defined for APPC/MVS.

Configuring CICS for Remote Debug sessions generally falls into two broad categories:

1. Configuring CICS for Remote Debug APPC session support.
2. Configuring VTAM, and possibly NCP, on how the workstations are connected. See the VTAM Resource Definition and the NCP Resource Definition manuals for more information.

The CICS configuration that is described is essentially independent of the type of network within which the workstations reside. However, network definitions in VTAM and NCP will vary depending on how partner workstations are connected. As was the case for MVS, our description is limited to a token ring LAN attached to the host via a 3745 communications controller (see "Defining the 3745 Attached LAN to VTAM" and "Defining the 3745 Attached LAN to NCP"). For further assistance in defining your network, contact your IBM representative or refer to the following publications:

These publications provide detailed information on the configuration process for CICS (V3.3 and V4.1) and VTAM (V3.4.1).

- CICS/ESA: Resource Definition Guide (SC33-1166)
- CICS/ESA: System Definition Guide (SC33-0664)
- VTAM: Resource Definition Reference (SC33-0666)
- VTAM: Network Implementation Guide (SC31-6434)
- NCP: Resource Definition Reference (SC30-3448)

#### Prerequisites

The following software levels are required for the definitions in this chapter:

- CICS/ESA 3.3 or later
- MVS/ESA 4.2 or later
- VTAM 3.4 or later
- NCP 5.2 or later

#### Terminology

Below is a table of standard APPC and equivalent CICS terms. Using standard terms makes configuring unlike platforms such as CICS and CM/2 for communications easier so standard terms are used whenever possible. Some terms have no CICS equivalent but instead are set in VTAM or NCP.

Standard Term | CICS Term
--- | ---
Link Name | PU name (VTAM)
Network Name | Network, NETID (see note)
LU Name | APPLID, ACBNAME
Partner LU Name | Netname
LAN Address | LOCADD (NCP)
Adjacent LAN Address | DIALNO (VTAM)

Note: CICS uses a network name only when defining CPI-C side information in a PARTNER definition.

#### CICS configuration variables

to create a worksheet that defines the listed symbols. These symbols and their corresponding values will be used to configure CICS for communication with CM/2 at the workstation.

#### Overview of CICS APPC configuration

Configuring CICS for Remote Debugger APPC sessions requires:

- Configuring CICS to run as a client
  - Defining CPI-C side information
  - Performing other client-related configuration activities
- Defining a Link to the LAN

Note: The SIT parameter ISC=YES must be specified.

#### Configuring CICS to run as a client

The following provides instructions for using CICS Resource Definition Online (RDO) to create and modify CICS definitions. To start Resource Definition Online, you must be logged on to CICS and your userid must be authorized to run the CEDA transaction.

You must define the following:

- a CONNECTION object (with the partner LU name)
- a SESSIONS object (with the mode name for the session)
- a PARTNER
- a PROFILE

In CICS, objects have properties such as authorization lists (which userids can use the object), resources required (memory, buffers), etc. CICS manages all these to provide low response time.

Note: To distinguish CICS objects, such as a CONNECTION, from more generic usages, the CICS object names will be in upper case.

To create and modify definitions in CICS start the CEDA transaction. All definitions in CICS are kept in groups. Most object identifiers must be globally unique, that is, cannot be used in any other group. SESSIONS objects are an exception to this rule. In the following sections all the definitions are in the same group.

##### Defining CONNECTIONS

A connection must be defined for each workstation participating in Remote Debug APPC sessions with CICS.

To define a connection in CICS, enter the following at a clear screen:

    ceda define connection(CON) group(GROUP)

CICS folds all characters to uppercase, so you don't have to worry about typing lower-case characters. If the group does not exist, CICS creates it for you automatically. Figure 30 shows the 3270 screen that results from this command.

##### Defining SESSIONS

Define the mode name and session characteristics for each PARTNERLU (or workstation) with a sessions definition that can be initiated by the following command:

    ceda define sessions(SESSION) group(GROUP)

Figure 31 shows the 3270 screen that you should get as a result.

##### Defining side information

Side information must be defined for each workstation participating in Remote Debug APPC sessions with CICS.

To define CPI-C side information in CICS, you must create a PARTNER definition and a PROFILE definition.

To create a PARTNER definition, enter the following command in CICS:

    ceda define partner(SYMDEST) group(GROUP)

The 3270 screen shown in Figure 32 should appear. Enter the values for Partner, Netname, Network, and TP name from the worksheet in "CICS Configuration Variables".

To define a PROFILE to explicitly set the mode name for the side information, enter the following command:

    ceda define profile(PROFILE) group(GROUP)

The screen shown in Figure 33 should appear. Enter the values for PROFILE and MODE from the worksheet in "CICS Configuration Variables".

##### Installing the definitions

Before any definitions can be used, they must be added to the running CICS System Definition (CSD) using the INSTALL command. This is accomplished by entering:

    ceda install group(GROUP)

This command installs all the objects in the group - CONNECTIONs, SESSIONS, etc. Some objects can be installed individually, too. If a resource is in use, or In Service in CICS terms, the installation will fail. If you get the INSTALLATION FAILED message, you can display the messages by pressing the PF9 key. However, this should not happen the first time.

If you need to acquire a CONNECTION, use the CEMT transaction.

Note: The above install command must be repeated after each cold start of the CICS region. If this results in a problem, use the following command instead:

    ceda add group(GROUP) list(LIST)

#### Defining a link to the LAN

These are identical when configuring for APPC/MVS. Check to see that such configuring has not already been done before proceeding further. If these definitions have not been performed, see "Defining the 3745 Attached LAN to VTAM" or "Defining the 3745 Attached LAN to NCP" for more information.

#### CEMT to display/modify sessions

In CICS, the CEMT transaction allows you to display and modify the status of connections, netnames, and modenames (that is, all sessions with a particular mode name):

    cemt inq netname(PARTNERLU)
    cemt inq modename(CON)

You might need to manually start a session between CICS and the partner LU. To start a session with the partner session, at a CICS screen enter this command:

    cemt inq con(CON)

You will get the screen shown in Figure 34.

By the connection and netname for the partner LU you should see Ins Acq. This is CICS shorthand for In-service, acquired. If the status is Ins Rel, overtype the Rel with Acq and press the enter key. The resulting screen should now have Ins Acq as the status. If not, contact your VTAM systems programmer and make sure that the partner LU is active. You can also use the VTAM command to display/activate the partner LU or switched major node.

When the connection is in service and acquired, you can start to use it for Remote Debug communications.