IMS Connect protocols

IMS™ Connect provides several different transaction protocols.

The protocols include:
  • Conversational support
  • Send only
  • RESUME TPIPE/Receive for asynchronous output
  • Socket connections
  • Asynchronous output support
  • Transaction restrictions and limitations
    The restrictions and limitations for transactions can differ depending on the specific transaction type.
  • Commit mode and synchronization level definitions
    IMS Connect supports the following commit modes and synchronization levels.
  • IMS Connect protocol level
    The IMS Connect protocol level identifies which transaction features and modes IMS Connect is configured to support.
  • IMS Connect conversational support
    A conversational program is a message processing program (MPP) that processes transactions made up of several steps. The MPP does not process the entire transaction at once.
  • Purging undeliverable commit-then-send output
    You can configure OTMA to purge commit-then-send (commit mode 0) IOPCB output when the output cannot be returned to the OTMA client application that initiated the transaction.
  • Rerouting commit-then-send output
    You can configure IMS to reroute commit-then-send (commit mode 0) IOPCB output to an alternate OTMA tpipe hold queue for retrieval.
  • Recoverable IMS transactions
    This topic contains scenarios for running recoverable transactions in the IMS Connect environment.
  • Send-only protocol
    Client application programs use the send-only protocol to submit commit then send (CM0) input messages to IMS in rapid succession without requiring the client application to wait for a response. The send-only protocol is designed for fast, high volume input.
  • Socket connections
    IMS Connect provides three kinds of client TCP/IP connection protocols, which are called sockets. The TCP/IP sockets define how IMS Connect manages client TCP/IP connections when IMS Connect sends a disconnect message.
  • IMS Connect timeout specifications
    You can specify timeout intervals to IMS connect for various stages of the communication process and for various types of interactions.
  • IMS Connect transaction expiration support
    IMS Connect can adjust the expiration time for IMS transactions to match the timeout value of the socket connection on which the transaction is submitted.
  • Retrieval of output on OTMA tpipe hold queues
    OTMA uses tpipe hold queues to send output to IMS Connect that must be queued for delivery. To retrieve output from the tpipe hold queue, the IMS Connect client issues a RESUME TPIPE request that specifies the name of the tpipe on which the output messages are queued.
  • IMS Connect client call flows
    The following examples show flows for IMS Connect client conversational and non-conversational transactions.
  • IMS Connect dead letter queue (HWS$DLQ)
    In certain instances, if OTMA receives a NAK response from IMS Connect, OTMA stores the undelivered message on the IMS Connect dead letter queue. The IMS Connect dead letter queue is identified by the tpipe name HWS$DLQ.
  • Ping support for IMS Connect
    To determine whether or not IMS Connect is available, you can send a ping request to IMS Connect. The ping support operates like a transaction and has the appearance of a transaction code and data. When you send the request PING IMS_CONNECT, the response is PING RESPONSE.
Parent topic: IMS Connect and TCP/IP communications