Client-Server Communication A widely used communication pattern in distributed systems is the client-server pattern, in which the server is a provider of a service and the client is a user of a service. The client initiates the communication, requesting that the server performs a service, transferring a parameter set if necessary. The server waits for incoming communication requests from a client, performs the requested service, and dispatches a response to the client´s request. The direction of initiation is used to categorize whether an AUTOSAR Software The component is a client or a server. A single component can be both a client and a server, depending on the software realization.