Correlating AS2 MDN to Original IDoc?

Question

Hi All -
I have got the following scenario:
1) Backend system (ECC) sends IDoc to SAP PI.
2) SAP PI maps IDoc to EDIFACT message and sends via AS2 to B2B Partner.
3) B2B Partner sends back AS2 MDN to acknowledge receiving of AS2 message.
__Question:__
How can I now correlate the AS2 MDN to the original IDoc and so forward the acknowledgement to the Backend system?
I was thinking to use the 'Correlation ID' which is contained in the AS2 MDN and is the same ID as the original SAP PI message.
However, how do I practically retrieve the IDoc number (part of original IDoc message and used as identifier in the ECC system) from the persisted messages of SAP PI?
Can I code an ABAP or JAVA program which is than called within a mapping to query the persisted messages and give back the correlating IDoc number?
Are there other ways to achieve this?
Thanks for your inputs.
Best Regards, Mathias.

Answer 1

Hi Mathias,
Approach1:
I would definately not consider using BPM overhead on a high volume scenario. As the Output file(that will be generated) will be a simple XML message with just the data required for corelating with the MDN. All MDN's are expected to received within 1 min or less than 5 min.(B'cos it is a System level Acknowledgement), Hence if the BPM is not closed within the specified time period(1min or 5 min), raise an exception.
The Corelation file that will be generated can look like
<MDN_Corr>
   <SenderAS1ID>        --> Will be used for Corelating the MDN
   <ReceiverAS2ID>      --> Will be used for Corelating the MDN
   <TimeStamp>
   <IDOCNumber>
   <EDI_ISA_Control_No> --> Will be used for Corelating the MDN
   <EDI_Message_Type> 
</MDN_Corr>
Approach2:
It might be very resource intensive to perform payload search. (and in some cases, the messages are archived, hence might result in bad search). Hence, you can have Z-Table all the fields as mentioned in the XML message. 1:1 mapping b/n EDI_ISA control number & IDOC_Number will be your lookup key-value params
-SM