One of the staples of modern computing systems is the concept of remote method invocation, where a client program calls a procedure or routine in another program running in a server process. This usually is confined to a single physical device, however. An extension of the same basic concept, called remote procedure call (RPC for short) allows a client to call a procedure or routine on a server that is running on a distant machine.

A server may itself be a client of another server, so RPCs can be chained. A server process has to have a defined format, called a service interface, that specifies the procedures that are available for remote calling. The service interface should specify which processes are eligible to be called remotely, what the format of a call should be, and what the range or type of acceptable...