IMS Connectivity in an On Demand Environment: A Practical Guide to IMS Connectivity

Chapter 9. IMS Connect user exit support 137

the client name. Previously, that was the only way to reroute the asynchronous output from

one OTMA-originated transaction to a different OTMA client, but now this function can be

done in DFSYPRX0. When OTMAMD is set to Y, DFSYPRX0 can and should make all

routing decisions. Refer to APAR PQ33996 for more details.

For more information about the OTMA prerouting exit and destination resolution exit, refer to

IMS Version 9: Customization Guide, SC18-7817.

9.5.2 How IMS Connect communicates with the DRU exit

In IMS Connect, the LTERM name is analogous to the unique clientID name for

commit-then-send message flow. To clarify whether a destination is for IMS Connect (through

OTMA), IMS uses a prerouting exit routine (DFSYPRX0) that can specify where IMS should

look to resolve the destination names. In this case, IMS needs to look at the IMS Connect

clientIDs, because the DRU exit cannot determine whether the message should be directed

to OTMA client (IMS Connect) or traditional IMS processing (ISRT to traditional LTERM or P

to P switching). Determining the destination for an OTMA (IMS Connect client) message

requires two phases:

1. DFSYPRX0 is called to determine the initial destination for the output.

The exit routine can determine whether the message should be directed to OTMA clients

or to IMS Transaction Manager for traditional IMS processing. The exit routine cannot

determine the final destination (Tpipe name).

2. The DRU exit routine (for example, the IMS Connect supplied exit HWSYDRU0) is called

to determine the final destination (Tpipe name) for the output.

Each OTMA client can specify a separate DRU exit routine. In other words, each OTMA client

can specify a single DRU exit for each copy of IMS Connect that is connected to a given

datastore (IMS). This means that one IMS Connect can have the same or a different DRU exit

for each of the datastore definitions in the IMS Connect configuration file.

9.5.3 HWSYDRU0 sample DRU exit

Figure 9-4 on page 138 shows the function of HWSYDRU0, the IMS Connect-supplied OTMA

DRU exit.

You can only use this exit under one of the following conditions:

 The IMS Connect clientIDs are named CLIENT01 through CLIENT09 and all belong to the

same member name.

 The IMS Connect clientIDs are as follows (in this case, Tpipe names are changed and

integrated into another name):

– TPIPE001 through TPIPE099 and all belong to member MEMBER0

– TPIPE100 through TPIPE199 and all belong to member MEMBER1

– TPIPE200 through TPIPE299 and all belong to member MEMBER2

– TPIPE300 through TPIPE399 and all belong to member MEMBER3

– TPIPE400 through TPIPE499 and all belong to member MEMBER4