0.30: What are Object Request Brokers (ORBs)?

An Object Request Broker (ORB) manages the interaction between clients and servers, using the Internet Inter ORB Protocol (IIOP). It enables clients to make requests and receive responses from servers in a network-distributed environment.

The ORB provides a framework for clients to locate objects in the network and invoke operations on those objects, as if the remote objects were located in the same running process as the client, providing location transparency. The client invokes an operation on a local object, known as a stub. Then, the stub forwards the request to the desired remote object, where the operation is executed and the results are returned to the client. The client-side ORB is responsible for creating an IIOP request containing the operation and any required parameters, and sending the request on the network. The server-side ORB receives the IIOP request, locates the target object, invokes the requested operation, and returns the results to the client. The client-side ORB demarshals the returned results and passes the result to the stub, which in turn, returns to the client application, as if the operation had been executed locally.