HL7 2.xml transport, HL7 3 transport, standard XML transport = SOAP?

Question

I am developing a small server with HL7 2.x support.

I've finished the MLLP reader (which accepts the HL7 2.x default, and now it is time to figure out how to accept HL7 2.xml.

However, I can find no information whatsoever on what transport is used for this!

I know it is generally less used, but surely someone must have implemented it at least once? How are you transporting the XML ?

The default is wrapped in MLLP (consists of a start byte and a couple end-bytes) ... SOAP strikes me as the obvious choice for the XML version of HL7 2.x, but I guess it also could be wrapped in MLLP. However, I'd prefer to know what is the standard.

Also, while i'm on the general topic:

How are HL7 3 messages wrapped ? Is there a usual case ... in general XML messages, when sent over a network, are transported using xxxxxx (again.. , SOAP?) thanks for any replies!

sean

ps Yes I am intentionally asking for HL7 2 (not 3) xml. Encoding as described here: www.hl7.org/documentcenter/public/wg/xml/drafts/v2xml1mlbb.pdf

Answer 1

Don't confuse the message format for the delivery mechanism. MLLP is certainly exceedingly common for HL7 2.x (enough that I've had clients just say "we send the messages via TCP/IP"), but it is just a message, you can send it any way you choose. I've two cases where the exchange of v2.x messages is partly file-system based (FTP/S in one case, network directory pickup in another).

Similarly for HL7 3, you can send the XML any way you want. I agree that SOAP seems natural given the XML format of the message, but I've honestly not had any client use the v3 format yet. I've also not had many clients "get" the notion of delivering HL7 messages via SOAP or a web service in general.

To reinforce my first point, if you look at an interface engine like Mirth Connect, you will see that the delivery mechanism is kept as an independent decision from the message format. I can deliver via file, LLP, FTP, Web Service, etc... and the message can be v2, v3, EDI, etc.