Outbound protocol message flow

The internal flow of outbound messages within the protocol thread involves many factors, including:

  • Time-out and retry management.
  • Start-up initialization of the TPS.
  • Message forwarding, if required, after they pass through TPS processing.

The normal outbound flow of a message through the protocol thread is:

  1. A message arrives by ICL from the translation thread.
  2. The message moves into the outbound pre-TPS queue.
  3. The message undergoes TPS processing in the appropriate outbound TPS modules.
  4. Any resulting protocol messages move into the appropriate outbound post-TPS queue.
  5. The message undergoes any prewrite UPoCs specified, and is then placed in the forward queue.
  6. The engine attempts to send the first outbound protocol message.

If the attempted send succeeds, then the engine removes the protocol message from the queue.

If the attempted send fails, then:

  • Time-out determines if and when the engine resends the message.
  • Retry values determine how often the engine resends the message.

If the number of attempted sends exceeds the retry value, then the engine does one of these:

  • Place the protocol message in the error database as undeliverable.
  • Forward the message if there is a forward host that is defined for the connection.