Chapter 14: Introduction to Remote IMS

This chapter describes Remote IMS and its installation and is intended primarily for use by the administrators of the IMS Option and IMS/ESA systems. To understand the content of this chapter, you need a general understanding of the IMS Option customization and configuration facilities and familiarity with APPC/MVS and IMS/ESA "CPI-C driven" transactions.

Micro Focus Remote IMS consists of Requester and Server software and provides access to IMS/ESA databases from Micro Focus IMS Option. The Requester software runs with the IMS Option on the PC and the Server runs on your IMS/ESA mainframe.

Database segment retrieval and update are transparent to the application program and require no changes to the application or the DBD or PSB source.

14.1 Customer Responsibilities

The installation and use of the Remote IMS software components is quite simple. Setting up your network and your mainframe system software may be more complex. A successful installation requires the coordination of various groups at a typical IMS/ESA site. You need to set up and support the PC and mainframe communications software definitions, the IMS/ESA system, security packages and any other software and hardware which may be required at your installation.

It is impractical, if not impossible, for us to describe all of the possible software and hardware configurations to meet all customer requirements. It is also impractical to list all of the software "pre-requisites", "co-requisites", "PUT-levels" and "PTFs" for all of the software involved. The chapters in the remainder of this Guide describe:

14.2 Terms and Acronyms

The following table lists terms and acronyms that you should be familiar with before reading this and following chapters.

CCI Short for Common Communications Interface, a Micro Focus communications architecture.
CPI-C Short for SAA Common Programming Interface for Communications. Intended as a high-level language for communications. It currently supports SNA LU 6.2 which is commonly referred to as APPC.
MFM Short for Mainframe Manager. Micro Focus middleware software that runs on the mainframe as a started task.
Remote Database An IMS database accessed from the IMS Option using Remote IMS.
Requester When capitalized, refers to Micro Focus Micro Focus Remote IMS Requester.
Server When capitalized, refers to to Micro Focus Micro Focus Remote IMS Server.

14.3 Communications Protocol Options

Remote IMS consists of the Remote IMS client software running on the PC workstation and the Remote IMS server running on IMS/ESA on your mainframe. You can configure Remote IMS to use either SNA or TCP/IP communications protocols.

14.3.1 SNA Communications protocol

When using SNA, the Remote IMS client communicates with APPC/MVS via a third party communications product such as Microsoft's SNA Server using the CPI-C API. The communications software communicates to APPC/MVS via an LU 6.2 (APPC) conversation.

On the mainframe, APPC/MVS connects to IMS/ESA for execution of the Remote IMS server software. The Remote IMS server also uses the CPI-C API for communicating with APPC/MVS.

14.3.2 TCP/IP Communications

TCP/IP support requires Mainframe Manager to function as a protocol converter. This allows the Remote IMS client to use TCP/IP while the Remote IMS Server uses SNA.

The Remote IMS client communicates with the MFM started task via Common Communications Interface (CCI) API which uses TCP/IP as the underlying protocol. On the mainframe, MFM receives the TCP/IP conversation from the client and opens an LU 6.2 conversation with APPC/MVS. APPC/MVS connects directly to IMS/ESA and the Remote IMS server functions the same as it does for the SNA Communications option. The server is actually unaware of the client communications protocol.

The TCP/IP protocol option does not require SNA on the workstation or workstation network environment.

An added benefit of using the TCP/IP protocol option is idle client timeout.

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