Request Flow

Figure 1 shows the general flow of inbound allocate requests to a server address space. In the figure, a server has registered to receive the allocate requests that arrive at LUA for TPA. APPC/MVS places these requests on an allocate queue to await retrieval by the server. To retrieve an allocate request, the server calls the Receive_Allocate service. The Receive_Allocate service provides the server with the conversation ID, which the server uses to communicate with the client TP that issued the allocate request.

Presumably, during the conversation, the server provides a service to the client TP, such as searching data that the server controls, and returning data to the client TP. At the completion of its processing, the server might determine that it will stop serving inbound conversations. At this point, the server calls the Unregister_For_Allocates service.

While this book also describes callable services that provide more advanced functions, "basic" servers require only the services that are shown in Figure 1. (For information about using these services, see The Basic Server Functions.)