Configuring the LLP Client ACKnowledgment Settings |
After you have provided the LLP Client connection information, the next step is to configure the ACKnowledgment Settings section:
- Select the Wait for ACK check box if you want the Iguana channel to wait for an acknowledgment message to be returned before it sends the next message. If you unselect this check box, all of the other fields in this section will disappear, as none of them need to be selected.
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| If you unselect Wait for ACK, the channel will log an acknowledgment message as an error and ignore it. Only unselect this check box if the receiving host does not send acknowledgment messages. | ||
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- In the ACK timeout field, type the number of milliseconds to wait for the target application to send an acknowledgment message. If an acknowledgment is not received during this time, the message is resent if the When ACK times out check box (described below) is selected.
- From the ACK verification list box, select the type of validation acknowledgment variation you want. The table below shows the possible settings and their meanings:
| Acknowledgment verification | Meaning |
|---|---|
| Any Message | Treat any message sent back by the target machine as a valid acknowledgment. |
| Any ACK Message | Use the VMD file provided in the Iguana install directory (ack_verify.vmd) to parse the acknowledgment and ensure that it is an HL7 message of type ACK. Iguana uses the message identity to verify that the acknowledgment is valid. |
| Verified ACK Message | This option provides the strictest acknowledgment checking. The ack_verify.vmd file compares the MessageControlID field in the MSH segment of the original message with the corresponding field in the ACK message. The acknowledgment message must be of type ACK. You can add even more stringent acknowledgment verification by adding fields to the MSH table in the VMD file and mapping them to the fields that you want to compare in the messages. For example, you might want to compare the message type in the acknowledgment message to the message type in the original message. For more information on how to create a custom VMD file to perform ACK verification, see Creating a Custom VMD File For ACK Verification. |
- If the ACK verification list box is set to Any ACK Message or Verified ACK Message, the ACK VMD path field appears:
In this field, you can type or browse for the location of the VMD file that parses the received ACK message to determine its validity. When you supply the file path, the absolute path is displayed. The default file, ack_verify.vmd, is typically fine to use.
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If the ACK verification list box is set to Verified ACK Message, the VMD file that handles the ACK verification will process both the ACK message and the original message. The ACK message is processed first. For an example of a VMD file that processes the ACK message and the original message, and uses the Python enqueue_message() function to send the original message to another channel, see Enqueueing the Original Message When Performing ACK Verification. Note that enqueue_message() was added to version 4.5 of Iguana. | ||
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To include the value of an environment variable in the file path, use ${name}, where name is the name of the environment variable that you have defined. For example, the file path ${MYDIR}\myfile.vmd includes the value of the MYDIR environment variable.
The iguana_dir environment variable, which is defined by Iguana, is set to be the location of the Iguana configuration directory. To include this directory in your file path, specify ${iguana_dir} as part of the path.
- In the Attempt to resend message section, select the When ACK times out check box if you want the channel to resend the message if an acknowledgment has not been received in the time specified by the ACK timeout field.
- Select the When ACK verification fails check box if you want the channel to resend the message if acknowledgment verification fails. (Acknowledgment verification is performed if the ACK verification list box is set to Verified ACK Message.)
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The When ACK verification fails check box is disabled if the ACK verification list box is set to Any Message, as no acknowledgment verification is performed. | ||
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- From the ACK error handling list box, select what you want the channel to do when acknowledgment validation fails or when the channel times out while waiting for an acknowledgment message, and any and all attempts to resend the message have failed. Select Stop channel if you want the channel to stop, or select Skip message if you want the channel to skip the message.
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New Feature in Iguana 4.1 Acknowledgment error handling is new in Iguana 4.1. | ||
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If either of the check boxes in the Attempt to resend message section is selected, the Number of resend attempts and Disconnect between resend attempts fields appear:
- In the Number of resend attempts section, select the Unlimited radio button if you want the channel to keep trying to send the message forever. If you select the other radio button, the number of attempts is limited; in the text box provided, type the maximum number of times to resend the message.
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If Iguana is unable to send a message, the channel will be stopped. | ||
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- Select the Disconnect between resend attempts check box if you want the channel to be disconnected between attempts to resend the message. If this check box is selected, in the Reconnect after text field, type the number of milliseconds to wait before reconnecting and resending the message.