plication is blocked till a response is received or a time out error occurs.
You can’t configure multiple receivers.
In Asynchronous Communication, you add an intermediate system or a middleware between two systems. When a Sender Application sends a request, it does not wait for the Receiver Application to send the response. If there is a failure due to some reason, the middleware is responsible for resending the message. If required, the receiving system can send a response back to Sender as a separate asynchronous call.
This approach in SAP PI is called Exactly Once (EO) or Exactly Once in Order (EOIO).
An intermediate system is a queue and message from A is first added to the queue and at receiver end, it is pulled from queue and send to receiver. The response message from system B follows the
You can also maintain order in certain situations as per business requirement by using First In First Out (FIFO). This scenario is called Asynchronous with order maintained or Exactly Once in Order (EOIO).
Asynchronous communication assures guaranteed delivery. If the receiver system is not available for sometime, then the intermediate queue keeps the message and it remains there till the receiver system is available and the message is pulled from queue and sent to receiver system.
This is recommended for modify operations like creating a purchase order or modify a purchase order
The following are the key advantages of asynchronous communication −
In case of failure, the SAP PI system ensures guaranteed delivery and will resend the message.
No configuration required for duplicate checks.
You can configure multiple receivers in this scenario.
Both the sender system and the receiver system need not be online at same time.
PI logs all the messages sent via asynchronous communication.
No time out as intermediate system keeps the message and response request.
The following are the key disadvantages of asynchronous communication −
In this scenario, the sender needs to correlate responses to request on its own.
Response message needs to be implemented and routed separately.
It doesn’t provide an immediate response.
SAP provides a middleware based on NetWeaver called the SAP NetWeaver Process Integration. SAP NetWeaver PI delivers a message in specific format called the Simple Object Access Protocol (SOAP-HTTP). This message contains a header and payload. The header contains general information such as the sender and receiver information and the payload contains the actual data.
System can communicate with SAP NetWeaver PI directly or with the use of adapters −