Ensemble HL7 Version 2 Development Guide
HL7 Dual Acknowledgment Sequences
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HL7 Dual Acknowledgment Sequences
Some systems require a dual acknowledgment sequence from Ensemble: an immediate 1-byte ACK, followed later by the full ACK message. One such system is the dual-channel iSoft iCM application. If your configuration includes a client system such as iCM that requires a dual acknowledgment sequence, you must set up a paired business service and business operation to enable Ensemble to provide the expected ACKs.
Ensemble provides specialized business host classes that you can use to define a dual acknowledgment sequence over TCP and HTTP.
Dual ACK Sequence for Incoming Messages
For messages entering Ensemble, the dual acknowledgment sequence works as shown in the following figure:
  1. The client application sends a message into Ensemble.
  2. The inbound ACK business service sends an immediate 1-byte ACK to the client application.
  3. The inbound ACK business service sends the message to its routing process.
  4. The routing process routes the message to its target via a business operation.
  5. The target application returns an ACK message to the business operation.
  6. Ensemble relays the ACK to the inbound ACK business service.
  7. The business service relays the ACK to its paired business operation.
  8. The business operation relays the ACK to the client application.
  9. The client application acknowledges the ACK message by returning a 1-byte ACK.
Dual ACK Sequence for Outgoing Messages
For messages leaving Ensemble, the dual acknowledgment sequence works as shown in the following figure:
  1. A business service sends a message to its routing process.
  2. The routing process routes the message to the outbound ACK business operation.
  3. The outbound ACK business operation relays the message to the target application.
  4. The target application acknowledges the message by returning a 1–byte ACK.
  5. The target application returns an ACK message to the inbound ACK business service.
  6. The business service sends an immediate 1–byte ACK to the target application.
  7. The business service relays the ACK to its paired business operation.
  8. The business operation relays the ACK message back to the business service.
  9. The business service receives the ACK to its original message.
Configuring a Dual ACK Sequence
To configure an Ensemble routing production to use the dual acknowledgment feature:
  1. Add a business service to the production.
    Choose EnsLib.HL7.Service.TCPAckInService or EnsLib.HL7.Service.HTTPAckInService as the business service class. It is not one of the standard HL7 Input options available from the Business Service Wizard, but you can choose it by selecting the Other option and identifying the class.
  2. Add a business operation to the production.
    Choose EnsLib.HL7.Operation.TCPAckOutOperation or EnsLib.HL7.Service.HTTPAckOutOperation as the business operation class. It is not one of the standard HL7 Output options available from the Business Operation Wizard, but you can choose it by selecting the Other option and identifying the class.
  3. Configure the following settings for the business service:
  4. Configure the following setting for the business operation: