CICS Transaction Gateway V5 The WebSphere ... - IBM Redbooks

8 CICS Transaction Gateway V5
On z/OS, the External CICS Interface (EXCI) is used in place of the Client
daemon, and provides access to COMMAREA-based CICS programs
(Figure 1-3). Consequently, the EPI and ESI interfaces are not available with the
CICS Transaction Gateway for z/OS. There are also a few differences between
the ECI support on z/OS and the ECI support using distributed platforms.
Java
Client
TCP or SSL
HTTP or HTTPS
Gateway
daemon
Protocol
handler
Figure 1-3 CICS Transaction Gateway: z/OS
CICS TG
libCTGJNI.so
EXCI
OS/390
JNI module
CICS
Server
The primary differences in the ECI support offered when the CICS TG is running
on z/OS are as follows:
► When using asynchronous calls, specific reply solicitation calls are not
supported.
► The user ID and password flowed on ECI requests are verified within the
CICS TG with RACF®; afterwards the verified user ID is then flowed onto
CICS.
► The ECIRequest method listSystems() does not return the list of usable
servers, since any CICS region within the Parallel Sysplex® can be reached.
MRO
IRC
Note: The Gateway daemon is not usually required when a Java
application executes on the same machine as where the CICS TG is
installed. In this situation, the CICS TG local: protocol can be used, which
directly invokes the underlying transport mechanism using the Java Native
Interface (JNI) module libCTGJNI.so.