Question: What is Remote Procedure Calls, RPC?

Answer: A request from one program that is located in one computer can be used by another computer in a network environment without understanding the underlying network details. This is done by a protocol called Remote Procedure Calls. In this client / server environment (network environment), the request is from a client to the server that provides the service from a server.

RPC is also called as inter-process communication. RPC extends the normal procedure calls across the network which is necessary in distributed computing models and for harnessing the power of the multiple processors.

In distributed systems, a client calls a procedure stored on a server. This is called calling a remote procedure stored on a server. Though, the call is made as if the procedure was stored on the local machine.

The steps in which a RPC is made are:

* The client calls the procedure
* The client stub builds the message.
* The message is sent over the network.
* The Server OS gives the message to the server stub.
* The server stub unpacks the message.
* The stub makes a local call to the procedure.
* The server does the work and returns the result to the server stub.
* The stub packs the message and traps to the kernel.
* The remote kernel sends the message the client kernel.
* The client kernel gives the message to the client stub.
* The client stub unpacks the result and gives to the client.