The asynchronous interaction model, illustrated in Figure 1.2, allows the caller to retain processing control. The caller code does not need to block and wait for the called code to return. This model allows the caller to continue processing regardless of the processing state of the called procedure/function/method. With asynchronous interaction, the called code may not execute straight away. This interaction model requires an intermediary to handle the exchange of requests; normally this intermediary is a message queue.While more complex than the synchronous model, the asynchronous model allows all participants to retain processing independence. Participants can continue processing, regardless of the state of the other participants.
Introduction to the Remote Procedure Call (RPC)The traditional RPC model is a fundamental concept of distributed computing. It is utilized in middleware platforms including CORBA, Java RMI, Microsoft DCOM, and XML-RPC. The objective of RPC is to allow two processes to interact. RPC creates the fac ¸ade of making both processes believe they are in the same process space (i.e., are