Computer Hardware User Manual

acknowledgement message. The MLLP V2 acknowledgement protocol is synchronous: the

source system will not send new HL7 content until an acknowledgement for the previous HL7

content has been received.

If the HL7 content (a query in the example below) triggers the sending of HL7 content (a

response) by the destination system, then this HL7 content is framed in a block and sent. MLLP

has no knowledge of the HL7 content, nor does it base any part of its behavior on HL7 content.

With the TCP/IP HL7 Adapter, a database is used to persist the message.

In inbound mode, once the message is received by the HL7 Adapter, it is persisted into the

database and a commit acknowledgement is sent to the sender before the HL7 message is passed

to the Collaboration level. If the persistence fails, a negative acknowledgement is sent to the

sender and the Collaboration receives null as its message. Inside the Collaboration, the message

received is null and the Collaboration returns without proceeding.

If the message received is a duplicate message and if an ACK/NAK is already available in the

persistence database, the same is retrieved from the database and sent to the sender. The

Collaboration receives null as the received message.

Source/Destination

HL7 Content: Query()

Commit Acknowledgement()

Destination/Source

HL7 Query/Response

FIGURE 23 InteractionDiagram

MLLP V2 and the Sample Projects

Sun Adapter for TCP/IP HL7 User's Guide 145