RPC – Remote Procedure Call

RPC or a remote procedure call, in the computer world, is required for a communication session of the inner processes. That will also let the computer programs to search out subroutines or else procedures for execution using any other address spaces. But all this can be done without a programmer’s coding facilitation in order to perform the remote interaction. Anyhow, a programmer can write the same code for the both local and remote subroutine.

Another point to be noted is that when at issue software is being used the object-oriented principals for the communication purpose then RPC will be either known as remote invocation or else remote routine invocation. But for the implementation of this concept, incompatible technologies usage is must.

Well! Message passing procedure involves the certain actions like when a remote procedure call, containing request message for the execution of specified procedures, is initiated from the side of client to a remote server that will further send a response in this course of action to the client so as to continue the process. But you can find out the variations and intricacies in different kinds of implementations which can lead to different and incompatible RPC protocols. But during the call processing by server, the client will remain blocked and on finishing the server’s processing, the client can launch an asynchronous request (XHTTP call) to the server.

But in case of the remote calls, you can face failure due to unpredictable and irregular network problems too. And all this can be happened without knowing that these remote procedures were actually called upon or not. On the other hand, procedures without added effects (known as idempotent procedure) can be easily handled if called excessively.

In addition to this, an event’s sequence in the course of a RPC can be as following:

  • The client dubs to the end (client stub) by means of a local procedure call (along with parameters).
  • The stub (client side) performs marshalling by packing parameters in the form of a message which is forwarded but after making a system call.
  • The client message is forwarded to the server via a kernel (at the server) which duty is to transfer the packets on their reception to the server side stub end and as a result this stub provokes the server procedure.

Remote Procedure Call Protocol’s Structure

The RPC message protocol can be divided into two distinct constructions:

  1. Call message
  2. Reply message.

RPC Call Message:

Every remote procedure RPC call message is consisted on unsigned integer fields for the identification of the each remote procedure. These fields can be as: Program numeral, Program version number and Procedure number.

RPC Reply Message:

But for a reply message (a request), RPC protocol can be varied in nature and its makeup is depending upon the call message acceptance and rejection by the server. A reply message towards a request may contain the information in order to distinguish the following conditions such as: is RPC carried out the call message effectively and is remote program not accessible on the distant system etc.

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