Timeout intervals for IMS Connect acknowledgments to OTMA

You can specify a timeout interval that determines how long OTMA waits for an acknowledgment from IMS Connect. You can also specify a timeout tpipe queue to hold commit-then-send (CM0) output after the timeout interval has expired.

You can specify a timeout interval by using the ACKTO parameter in the DATASTORE configuration statement. The timeout value specified on the ACKTO parameter applies to acknowledgments sent to OTMA for the following message types:

Transaction messages sent to a remote IMS system
CM0 output
Send-then-commit (CM1) output

For transaction messages that are sent to a remote IMS system, if the ACK timeout interval expires, OTMA reroutes the transaction message to the timeout queue. If OTMA receives an ACK response from the local IMS Connect after a transaction message has timed out, OTMA issues a NAK with X'2B' return code to the local IMS Connect.

For CM0 output, when the timeout interval expires, OTMA removes the output from the tpipe queue and reroutes the output to either:

A specified reroute tpipe queue
A specified timeout tpipe queue
The default OTMA timeout tpipe queue DFS$$TOQ

You can specify the name of a timeout tpipe queue for CM0 output and for transaction messages that are sent to remote IMS systems on the CM0ATOQ parameter in both the HWS and DATASTORE configuration statements.

On the HWS configuration statement, the CM0ATOQ parameter defines a default timeout tpipe queue for all data store connections defined to an instance of IMS Connect. On the DATASTORE statement, the CM0ATOQ parameter defines the timeout tpipe queue to be used by only the defined data store connection. Specifications for CM0ATOQ on the DATASTORE statement override the specification for CM0ATOQ made on the HWS configuration statement.

CM1 output is not rerouted to a timeout queue, because OTMA discards CM1 output if the timeout interval expires.

When a timeout occurs, and the IMS application does not reply to the IOPCB or complete a message switch to another transaction, OTMA issues a DFS2082 message for both CM0 and CM1 input messages, regardless of the transaction response mode.