RPC Message Protocol

In an IT field or any company, the computer systems are interconnected to the same server to share information among them. It follows distributed information systems, in which every computer is physically connected and connected to a common network. RPC stands for Remote Procedure Call which is a type of protocol used in the operating system for making communication over remote devices. Using the RPC message protocol, the message request is sent and after getting the reply the communication is established.

Remote Procedure Call

The TCP/IP or UDP comes under the low-level transport layer protocol for communication between the networks and the RPC protocol is considered a high-level protocol. The RPC is a very simple call syntax and is understandable. When the request is sent from this RPC, then we can wait for numerous replies from different systems.

RPC Message Protocol

RPC message protocol is a communication protocol for the client and server application. This message protocol will be performed based on two main steps namely −

  • RPC Call Message

  • RPC Reply Message

1. RPC Call Message

This message would be forwarded to the server which came from the client and it particularly includes the unsigned integer data type to uniquely determine the procedure call like −

  • Program number

  • Program version number

  • Procedure number

2. RPC Reply Message

The Reply message is completely dependent on whether the call request is approved or denied by the remote server. In this, the structure will also be in two forms; if one failed the other form is chosen.

Case-1 - When the request is accepted

The RPC call request will be completely executed without any error.

Case-2 – When the request is denied

Again in this case rejection, there are two possibilities, one is that it does not belong to the compatible RPC version and the other is that the authentication failed.

RPC message Protocol Requirements

There are primary conditions included −

  • There should be a match between call and reply messages.

  • This RPC protocol must follow a unique procedure call.

  • The communication between the client and server needs to be authenticated.

Procedure for call and reply Message

  • The client call is made and is ready to pass to the remote server.

  • The call message along with its parameters is packed into a form called marshaling.

  • Then the message is forwarded to the server side from the client.

  • On the server side, the received message is unpacked that decrypted with the unique code, and the process is called unmarshalling.

  • Finally, the server accepts the remote procedure call.

Advantages of RPC Protocol

  • It changed the conventional method of communication between the client and server into a high-level language.

  • It is mainly used in the distributed information system in which the computers are interlinked with each other.

  • The messages are delivered regularly.

  • Both the process and thread-oriented architectures are supported by RPC.

  • It hides the backend process from the user and shows only the output.

  • The code is very easy so if any error occurs, it can be debugged or we can rewrite it easily.

  • It does not allow all the protocols for the procedural call and thus improving the efficiency of the communication system.

Disadvantages of RPC Protocol

  • Based on the call request and reply the data transfer is possible, but it is not suitable for a large amount of data as the client and server work on environments.

  • Communication is established between different systems and processes, so they are prone to failure easily.

  • The version of RPC is not uniform and the implementation can be done in different ways.

  • Based on the request, the communication process takes place, so it does not follow any particular architecture.


Remote Procedure calls can be accepted if authentication, versions used, and the match between the messages are. Depending on this communication can be deployed or rejected. The cost to implement this RPC protocol in distributed systems has been raised and it’s just a setup cost. But the cost of coding is completely minimized due to high-level language.

Updated on: 03-May-2023


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