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Keep Alive Messages

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A new feature introduced in version 4.3 "Keep Alive" messages allow you to create an HL7 message that can be sent to any UltraPort HL7 Listener at any time to determine whether that particular listener is up and receiving messages. When an UltraPort Listener receives a "Keep Alive" message it will always implement the following behavior:


1.It will ALWAYS acknowledge the message with a positive HL7 ACK.

2.It will (if traffic logging is enabled in the Global Settings) log the receipt of the message in the daily traffic log.

3.It will NOT write the HL7 message to the Data Folder (see Listener Profiles).

4.It will NOT forward the HL7 message to a Proxy Application (see Optional Profile Settings).


Help1_16 HOW is this useful? Well that depends. Customers have reported problems with VPN software or Network Security Software (like Norton or McAfee) which will periodically close or kill TCP/IP socket connections that have been idle for longer than <xx> amount of time. Having the ability to send a message like this will also allow HermeTech and our customers to create custom Listener monitoring applications without having to worry about "Keep Alive" / "Test" messages actually being delivered to the listener data folder and accidentally processed in a production environment.


Help1_16 HOW does it work? It's really quite simple to create a "Keep Alive" message. You just create ANY kind of structurally correct HL7 message and put this value (TEST-EA86F675F0324D979765D6A07C) anywhere in the HL7 message and then have any HL7 sending application send that message to the Listener. We call this value the "Test Handle"


Here's an example of a "Keep Alive" HL7 message. In this instance the Test Handle is in the Patient Last Name position in the PID segment:





And Another where the Test Handle is in the Sending Application position of the MSH segment:





Rules for Keep-Alive messages.


The Message Type (MSH Field 9 Component 1) must NOT be ACK.

The Test value (shown highlighted in yellow above) IS case-sensitive so you must enter it exactly as shown anywhere in the message.

The HL7 message must be a structurally correct HL7 message with at least 2 segments (the MSH segment + 1 more). What do we mean by structurally correct? This simply means that your HL7 message must be properly formed, with the MSH as the first segment and at least 1 additional segment.


Starting with Version 4.3 the UltraPort Listener installs an example file containing a Keep-Alive message in the program folder. The file is named HermeTechKeepAliveMessage.hl7. You can use the HL7 Router Simulator program to test how this functionality works.



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