In a CICSplex, resources (for example, transactions or programs) required
by one region may be owned by another region (the resource-owning region).
For example, you may have a terminal-owning region that requires access to
transactions owned by an application-owning region.
- Static routing
- means that the location of the remote resource is specified at design
time. Requests for a particular resource are always routed to the same region.
Typically, when static routing is used, the location of the resource is specified
in the installed resource definition.
- Dynamic routing
- means that the location of the remote resource is decided at run time.
The decision is taken by a CICS®-supplied user-replaceable routing program. The routing program may, at different times, route requests
for a particular resource to different regions. This means, for example, that
if you have several cloned application-owning regions, your routing program
could balance the workload across the regions dynamically.
All the following can be dynamically routed:
- Transactions started from terminals.
- Transactions invoked by a subset of EXEC CICS START commands.
- CICS-to-CICS distributed program link (DPL) requests.
- Program-link requests received from outside CICS--for example, External
Call Iinterface (ECI) calls received from CICS Clients.
- CICS business transaction services (BTS) processes and activities. (BTS is described in the CICS Business Transaction Services manual.)
- Method requests for enterprise beans and CORBA stateless objects. (Enterprise
beans are described in the Java™ Applications in CICS.)
Bridge 3270 transactions.
Some further definitions are necessary:
- Requesting region
- The region in which a transaction or other routable request is issued.
Here are some examples of what we mean by "requesting region":
- For transactions started from terminals, it is the terminal-owning region
(TOR).
- For transactions started by EXEC CICS START commands, it is the region
in which the START command is issued.
- For "traditional" CICS-to-CICS DPL calls, it is the region in
which the EXEC CICS LINK PROGRAM command is issued.
- For program-link calls received from outside CICS, it is the CICS region
which receives the call.
- For BTS processes and activities, it is the region in which the EXEC
CICS RUN ACTIVITY ASYNCHRONOUS command is issued.
- For method requests on enterprise beans or CORBA stateless objects:
- If the method call is issued outside CICS--for example, by a remote
(non-CICS) IIOP client--the requesting region is the listener region
which receives the call.
- If the method call is issued inside CICS--for example, by an enterprise
bean object that calls a method of another enterprise bean--the requesting
region is the region on which the call is issued.
- Routing region
- The region in which the routing program is invoked for route selection.
With two exceptions, the requesting region and the routing region are always
the same region. The exceptions are:
- Some terminal-related START commands:
- Because a terminal-related START command is always executed in the terminal-owning
region, the requesting region and the routing region may or may not be the
same. (This is fully explained in Routing transactions invoked by START commands.)
- The routing region is always the TOR.
- Some method requests for enterprise beans or CORBA stateless objects issued
inside CICS:
- An enterprise bean, program, or object on the local EJB/CORBA server calls
a method of an object on a remote EJB/CORBA server. The requesting region
is the local region on which the method call is issued. The routing region
is the listener region on the remote EJB/CORBA server.
- Target region
- The region in which the routed transaction or request executes.

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