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DirectConnect for DB2/MVS Connectivity Guide

Chapter 1: Introduction

Chapter 1

This guide describes how to connect a server on a local area network (LAN) and an MVS mainframe so that DirectCONNECT for DB2/MVS can access the target Database 2 (DB2) database.

Before you install DirectCONNECT for DB2/MVS, you must first establish the communications link required to access target data. This guide describes this communications link between the MVS mainframe containing the target data and the server.

Specifically, this chapter introduces you to the concepts and implementation of connectivity in the following sections:

• Connectivity at the MVS Mainframe
• LU6.2 Environment
• TCP/IP Environment
• Server Environment on the LAN
• Configuration and Connectivity Testing
• Product Name Changes

Connectivity at the MVS Mainframe

In the network configuration described in this guide, the MVS mainframe is the location in which target tables and customer data are stored.

In this guide, the MVS mainframe is an IBM System/390 or System/370 running the MVS operating system. Within the MVS mainframe, several products are required to communicate with the server:

• Customer Information Control System (CICS), a transaction monitor for the mainframe, which runs on the MVS operating system.
• One of the following communications protocols that enables the mainframe to communicate with the server:
  • Advanced Program-to-Program Communication (APPC) facility, also called Logical Unit Type 6.2 (LU6.2) or SNA, for LU6.2 environments. APPC uses the Virtual Telecommuni-cations Access Method (VTAM) and, optionally, the Network Control Program (NCP) as the mainframe access methods.
  • Transmission Control Protocol/Internet Protocol (TCP/IP) for MVS, which is a general-use communications protocol.

The following figure shows how these programs interrelate with one another.

Figure 1-1: Network connectivity and communications protocols

The following sections describe the changes you must make to each of these environments. For the sake of simplicity, these environments are referred to as the LU6.2 environment and the TCP/IP environment.

Note: This guide contains information on version sensitivity later in the guide. See the IBM documentation for the versions of communications software (NCP and VTAM) and database software appropriate to your site's LU6.2 or TCP/IP environment. See the vendor documentation for the communications configuration utility you use in your environment.

LU6.2 Environment

In the LU6.2 environment, the server must appear to VTAM as a Node Type 2.1 node capable of LU6.2 sessions to CICS. This means you must provide information about:

• The physical communications link
• The terminal definitions for CICS
• Whether single or parallel sessions are used
• The VTAM and NCP properties

Chapter 4, "Configuring the MVS Mainframe for an LU6.2 Environment," provides instructions for supplying this information. In addition, Appendix A, "LU6.2 Configuration Worksheets," contains platform-specific worksheets summarizing most of the required information.

Physical Communications Link

The LU6.2 communications uses a physical link that can take a variety of forms and can contain multiple components including front-end processors (FEPs), cluster controllers, and so on.

Figures 4-1 through 4-3 in "Sample VTAM/NCP Definitions" in Chapter 4 show examples of LU6.2 networks. This section also shows sample VTAM and NCP definition sets for each of these connection types.

CICS Properties

Within CICS, you must create terminal definitions for all client nodes that will access CICS through APPC. Terminal definitions are contained in the Terminal Control Table (TCT). In addition, the CICS System Initialization Table (SIT) must include the setting ISC=YES so that the InterSystem Communication (ISC) setting allows support of APPC.

You can create or modify terminal definitions by:

• Editing the DFHTCT definition
• Using the Resource Definition Online (RDO) utility

For additional information about DFHTCT definitions and how to use the RDO utility, see the appropriate IBM documentation.

DFHTCT Definition

A DFHTCT definition contains information about properties, such as some of the following:

• Access method
• Autoconnect
• Single or parallel sessions
• Buffer size
• User security level

Resource Definition Online

If you are using Resource Definition Online (RDO) to create or modify terminal definitions, you must define several resource types, which vary for single sessions or parallel sessions.

• For single sessions, you must define TYPETERM and TERMINAL resource types.
• For parallel sessions, you must define CONNECTION and SESSIONS resource types.

Parallel Sessions

To use parallel sessions, you must specify certain properties that are optional or are not coded for single sessions. Some installations initially specify only those properties needed for single sessions to test the operability of the system. When production begins, parallel sessions are used.

If you plan to use parallel sessions and you want a list of the specific parallel session properties, see "Properties for Parallel Sessions" in Chapter 4, "Configuring the MVS Mainframe for an LU6.2 Environment."

VTAM and NCP Properties

For the MVS mainframe to communicate successfully with DirectCONNECT, you must define your network to VTAM and, depending on your type of networking, NCP.

• VTAM is the software subsystem that resides on the mainframe and provides the network access for mainframe-based SNA applications.
• NCP is the operating software used by the front end processor (FEP) if your installation uses one. NCP primarily attaches a large number of lines that, in turn, connect to remote devices or nodes on the network, such as DirectCONNECT for DB2/MVS.

When used with Sybase EnterpriseCONNECT, VTAM and NCP must have information about the logical and physical units that communicate with each other, and about the SDLC, Token Ring, or Ethernet link being used. Tables that VTAM and NCP share store this information.

The communication facilities available to you when you run EnterpriseCONNECT components depend on the versions of VTAM and NCP you run. For example, if your environment includes an FEP and you plan to use parallel sessions, you must have VTAM version 3.1, and NCP version 4.3 or version 5.2. If you do not have an FEP or are using a single session, you can specify all the required properties in VTAM.

For details on the following VTAM guidelines and standard IBM property settings, see the IBM CICS/MVS Intercommunication Guide.

TCP/IP Environment

In the TCP/IP environment, the communications protocol is TCP/IP running on the MVS operating system, and it is configured to process communications between the MVS mainframe and the server. Therefore, you must:

• Make modifications to MVS
• Configure TCP/IP for your MVS mainframe

These actions are described in Chapter 3, "Configuring the MVS Mainframe for a TCP/IP Environment."

MVS Modifications

To authorize TCP/IP dataset libraries and to update the appropriate members in those libraries, you must modify the MVS partitioned dataset, SYS1.PARMLIB.

TCP/IP Configuration

When you install DirectCONNECT for DB2/MVS, the CICS TCP/IP Sockets Interface communicates with it. To enable the communication, you must do the following:

• Define the port in the MVS TCP/IP configuration profile port definition for each CICS region that is used.
• Install and configure the CICS TCP/IP Listener transaction in the CICS region.
• Configure TCP/IP for MVS so that the server on which DirectCONNECT for DB2/MVS is installed can open a socket to the CICS region.

Server Environment on the LAN

For each of the following platforms, you use the indicated server to provide the LAN communications software:

Table 1-1: Server platform and communications software

Platform	Communications Software
HP-UX	HP SNAplus
IBM RISC System/6000	IBM SNA Server/6000
Microsoft Windows NT	Microsoft SNA Server for Windows NT
Sun/Solaris	Sunlink Peer-to-Peer

Configuration and Connectivity Testing

After you configure both the MVS mainframe and the server, and before you install DirectCONNECT for DB2/MVS, you can use the following utilities to confirm access to the mainframe on which your target database resides:

• snaping tests the APPC/LU6.2 connection, which is described in Chapter 9, "Testing Connectivity in an LU6.2 Environment."
• cicsping tests the TCP/IP connection, which is described in
  Chapter 8, "Testing Connectivity in a TCP/IP Environment."

These utilities ensure that your communications link functions properly. The snaping and cicsping utilities do not use DirectCONNECT for DB2/MVS code; they check the external connectivity after you configure both the MVS mainframe and the server.

The snaping and cicsping utilities are on media that accompanies DirectCONNECT for DB2/MVS. They are also on the program tape for MainframeCONNECT.

Product Name Changes

For this release, the names of some of the individual product names within the Sybase Enterprise CONNECT set changed. (Sybase Enterprise CONNECT consists of the Sybase products that allow client applications and mainframes to exchange data.) The names of the individual products changed as shown in the following table.

Table 1-2: Product name changes

Old Name(s)	New Name(s)
MDI Access Server for MVS-CICS or OmniSQL Access Module for DB2 (DB2 Access Module)	MainframeCONNECT
Open Server/Mainframe	Open ServerCONNECT
Open Client/Mainframe	Open ClientCONNECT
Net-Gateway, with: Mainframe Server Gateway (MSG) Mainframe Client Gateway (MCG) and MDI Database Gateway Access Server	DirectCONNECT, with: Transaction Router Service (TRS) Mainframe Client CONNECT (MCC)
MDI Database Gateway	DirectCONNECT for DB2/MVS Access Service DirectCONNECT Server