Interoperability with IBM Host Systems
Interoperability with IBM Host Systems |
|
Table 10.6 summarizes SNA Server client-to-mainframe services supported on each desktop platform.
Table 10.6 Heterogeneous Client to Mainframe Integration
| Desktop Platform | LU Types/Telnet Services | SNA APIs |
|---|---|---|
| LU0, LU1, LU2, LU3, and LU6.2. TN3270, TN3287, and TN3270E. | APPC, CPI-C, Common Service Verb (CSV), and LUA Request User Interface (RUI). | |
| Windows 3.x, Windows for Workgroups | LU0, LU1, LU2, LU3, and LU6.2. TN3270, TN3287, and TN3270E. | APPC, CPI-C, CSV, LUI RUI, LUA Session Level Interface (SLI), and ODBC/DRDA. |
| OS/2 | LU0, LU1, LU2, LU3, and LU6.2. TN3270, TN3287, and TN3270E. | APPC, CPI-C, CSV, LUA RUI, and LUA SLI. |
| Macintosh | TN3270, TN3287, and TN3270E. | (Uses Telnet-based services.) |
| UNIX1 | LU0 and LU6.2. TN3270, TN3287, and TN3270E. | APPC, CPI-C, CSV, and LUA RUI. |
| Windows 95 and Windows 98 | LU0, LU1, LU2, LU3, and LU6.2. TN3270, TN3287, and TN3270E. | APPC, CPI-C, CSV, LUA RUI, LUA SLI, ODBC/DRDA, and AFTP. |
| Microsoft® Windows NT® Workstation 4.0 and Windows 2000 Professional | LU0, LU1, LU2, LU3, and LU6.2. TN3270, TN3287, and TN3270E. | APPC, CPI-C, CSV, LUA RUI, LUA SLI, ODBC/DRDA, and AFTP. |
| 1 The UNIX client can use services beyond the Telnet-based services by using a third-party UNIX client for SNA Server developed by Parker Software in cooperation with Microsoft. For more information about the UNIX client for SNA Server, see http://www.microsoft.com/. |
SNA Server supports standard terminal and printer sessions with LU types 0 through 3. LU 0 is a device-independent LU used mainly in the financial industry to support teller terminals and automatic teller machines. LU types 1 and 3 are used to support printer emulation programs on client and server computers, including SNA Server's Host Print Service. LU type 2 provides terminal emulation support for a broad range of client 3270 emulator programs.
LU 6.2 supports Application Program-to-Program Communications (APPC), Common Programming Interface for Communications (CPI-C) and Common Service Verb (CSV). These APIs allow client- and server-based transaction programs and other processes to communicate with host systems, such as those running under IBM Customer Information Control System (CICS) and Information Management System (IMS). An example of a transaction-based process is a magnetic credit card reader at a point-of-sale terminal, such as a computer-based cash register that communicates from a branch store location to the home office through an SNA Server connection. The process to validate the cardholder's credit status uses APPC as the API supporting the transaction.
As shown in Table 10.6, SNA Server offers a number of utilities that complement standard terminal and printer emulation sessions. One such utility is APPC File Transfer Protocol (AFTP). AFTP is part of a group of applications supported by the IBM APPC applications suite running on OS/390, MVS, VM, or OS/400.
As a server-based solution, AFTP works with SNA Server's FTP-to-AFTP gateway to provide a seamless means for clients to send and receive flat files to and from host systems. SNA Server converts the FTP commands to AFTP and uses APPC between the SNA Server–based computer and the host system. This allows the client to use an open TCP/IP protocol, while the host runs only its native SNA protocols. The result is greater efficiency and simplified management at the client and the host system.
SNA Server includes a Software Development Kit (SDK), with online documentation and source code examples. This SDK provides the means to build complete AFTP, APPC, CPI-C, CSV, and LUA solutions, as well as add-on products to SNA Server core functionality. LUA is a customizable API that allows you to develop either at a low level in the SNA protocol stack, at the Request User Interface (RUI), or at a higher level, at the Session Level Interface. These APIs are commonly used by large institutional organizations building upon their legacy of banking and insurance applications, many of which had previously relied upon specialized control unit devices, such as the IBM 4147 financial series controller.
One series of APIs not directly supported by the SNA Server SDK are, High Level Language API (HLLAPI), Extended HLLAPI (EHLLAPI), and Windows HLLAPI (WinHLLAPI).
SNA Server APIs comply with the Windows Open Service Architecture (WOSA) guidelines. This means that on all Windows operating systems, the SNA Server APIs are WOSA versions: WinAPPC, WinCPI-C, and WinCSV.
Several independent software vendors (ISVs) contributed to the WOSA SNA API standards, among them IBM and Novell. Most major Windows SNA ISVs support WOSA APIs directly in their products, including Andrew, Attachmate, Eicon, NetManage, NetSoft, Wall Data, and WRQ. SNA Server's APIs comply with the standards published for other common operating systems as well. For example, on
SNA client emulation vendors also support host connectivity through SNA Server by adapting their products to support the SNA Server Function Management Interface (FMI)—also called the Emulator Interface Specification (EIS). The FMI or 3270 EIS API is encapsulated in the SNA Server Client software. The emulator communicates with this SNA Server Client software, which in turn communicates with SNA Server through an SNA Server client/server connection. When you use a full-featured 3270 emulator with SNA Server, you are connecting to the SNA Server through the FMI. FMI supports LU types 1 through 3.