Remote Procedure Call (RPC)

• Remote procedure call (RPC) is the basis of most client/server systems. Think of RPC as a procedure call where the procedure is located on a different computer than the caller. Thus, when the procedure is called, its parameters are passed (sent) via the network to the remote computer, and then the remote computer executes the procedure, returns the result(s).
• The RPC can be constructed on top of sockets. That is, the socket mechanism can be used to pass parameters and the name of the procedure to be activated on the remote computer, and so on.
• The remote procedure call mechanism is simple to use because it looks much like any other procedure call familiar to programmers. However, it covers up many complexities.
• The RPC can be blocking or nonblocking. A blocking RPC means that the program that places the call is stopped in its tracks while waiting for a reply. The nonblocking RPC, however, allows the calling program to continue without waiting for a reply. In this case, the caller must explicitly ask for the reply at some later time, or else the return value will never get back to the caller.