Figure 5 shows the main interfaces to IMS TM (the OTMA interface, the IMS Connect function, VTAM, and APPC), along with some of the products and protocols that use these interfaces.

Figure 5. Accessing IMS TM from Other Programs

The following components and products are shown in Figure 5:

• DL/I.
• Advanced Program-to-Program Communications (APPC): An implementation of the SNA LU 6.2 protocol that allows interconnected systems to communicate and share the processing of programs. For more information about IMS TM and APPC, see the complete version of An Introduction to IMS.
• z/OS Communications Server: z/OS Communications Server provides both System Network Architecture (SNA) and Transmission Control Protocol/Internet Protocol (TCP/IP) networking protocols for z/OS. The SNA protocols are provided by Virtual Telecommunications Access Method (VTAM) and include Subarea, Advanced Peer-to-Peer Networking, and High Performance Routing protocols. For more information on z/OS Communications Server SNA protocols or TCP/IP networking protocols for z/OS, see z/OS V1R4.0 z/OS Communications Server SNA Network Implementation Guide.
• Communication Controller and Network Control Program (NCP): A combination of hardware and software that provides support for single-domain, multiple-domain, and interconnected network capability. The NCP is an IBM licensed program.
• SNA Network: Existing (traditional) network that implements the SNA protocols⁶ to connect terminals and other devices.
• Server Layer for End User: One or more middleware software products that interact with the end user, for example, TN3270 client (TN3270 Telnet server acts as an interface between IP and SNA networks), WebSphere Application Server, or WebSphere MQ Everyplace®.
• Control Center for IMS: A workstation graphical interface from which you can manage your IMS systems. The Control Center connects to IMS through a TCP/IP network, IMS Connect, and the Structured Call Interface (SCI). For more information about the Control Center, see IMS Control Center.
• OTMA: An open interface to IMS TM through which a z/OS or TCP/IP application program can send a transaction or command to IMS without using SNA or VTAM.
• IBM WebSphere MQ for z/OS: A z/OS subsystem that supports the transfer of messages across z/OS address spaces and to other WebSphere MQ products on both IBM and non-IBM platforms. The platforms include AIX, iSeries, OS/2, VSE/ESA, HP-UX, Solaris, Windows, Compaq NonStop Kernel, Compaq Tru64 UNIX, Compaq OpenVMS (Alpha), and Linux, using the SNA LU 6.2 or TCP/IP communications protocols.
• CICS: In Figure 5, CICS application programs that need to access IMS TM can do so by using the OTMA callable interface.
• DB2 UDB for z/OS: IBM's premier database manager for relational databases. IMS TM can provide transaction processing services for DB2 UDB for z/OS.