Standards for Technology in Automotive Retail
Two-way communication in the context of this document refers to the pattern in which both communicating partners have the ability to initiate and receive messages at the same time. This type of communication is possible if both parties satisfy the service provider requirements described in Service Provider Requirements section.
Synchronous communication is done the same way using ProcessMessage as it is done in the one-way pattern (seeFigure 3.1, “One-way Asynchronous Communication” ). The difference here is that both parties can initiate the requests and hold for a response. Business requirements and an agreement between the two communicating parties determine weather and when synchronous communication is appropriate versus asynchronous communication.
Asynchronous communication changes a little bit from the way it is done in the one-way communication pattern. In the one-way approach, the client sends a request using PutMessage, and then sends another request using PullMessage to download the response from the server. In the two-way approach, the need for PullMessage diminishes and is replaced instead by PutMessage initiated by the server to the client as shown in the figure below.