Remote procedure call is used to mount remote clients to 
the servers.

Remote Procedure Call (RPC) is a protocol that one program 
can use to request a service from a program located in 
another computer in a network without having to understand 
network details. (A procedure call is also sometimes known 
as a function call or a subroutine call.) RPC uses the 
client/server model. The requesting program is a client and 
the service-providing program is the server. Like a regular 
or local procedure call, an RPC is a synchronous operation 
requiring the requesting program to be suspended until the 
results of the remote procedure are returned. However, the 
use of lightweight processes or threads that share the same 
address space allows multiple RPCs to be performed 
concurrently. 
When program statements that use RPC are compiled into an 
executable program, a stub is included in the compiled code 
that acts as the representative of the remote procedure 
code. When the program is run and the procedure call is 
issued, the stub receives the request and forwards it to a 
client runtime program in the local computer. The client 
runtime program has the knowledge of how to address the 
remote computer and server application and sends the 
message across the network that requests the remote 
procedure. Similarly, the server includes a runtime program 
and stub that interface with the remote procedure itself. 
Results are returned the same way.