In the realm of computer networking, an RPC server stands for a Remote Procedure Call server. It’s a powerful protocol that enables a program on one computer to request a service from a program located on another computer across a network, all without needing intricate knowledge of network operations. Think of it as a digital assistant that can ask for information or actions from another computer on your behalf.
At its core, RPC operates on the client-server model. The program initiating the request acts as the client, while the program providing the service is the server. This interaction mirrors a local procedure call, where one part of a program calls another. However, with RPC, this call extends over a network, making it possible for applications to be distributed across different machines. Like a regular function call, RPC is typically synchronous, meaning the requesting program pauses until it receives a response from the remote procedure. Modern implementations, however, can use lightweight processes or threads to handle multiple RPCs concurrently, boosting efficiency.
When a program using RPC is compiled, a crucial component called a stub is included. This stub acts as a stand-in for the remote procedure. When the program runs and initiates an RPC, the stub intercepts the request and forwards it to a client runtime program within the local computer. This runtime program is responsible for understanding how to communicate with the remote computer and server application. It packages the request and sends it across the network. On the server side, a similar process occurs. The server has its own runtime program and stub that interact with the actual remote procedure being called. The results are then sent back through the same path.
Several RPC models and implementations exist, with the Open Software Foundation’s Distributed Computing Environment (DCE) being a well-known example. The Institute of Electrical and Electronics Engineers (IEEE) has also standardized RPC in its ISO Remote Procedure Call Specification. In the context of network communication, RPC operates across both the Transport and Application layers of the Open Systems Interconnection (OSI) model. This positioning highlights its role in facilitating communication between applications across networks. RPC simplifies the development of distributed applications by abstracting away the complexities of network communication, allowing developers to focus on application logic rather than network details.
Alternatives to RPC for client-server communication include message queuing systems and IBM’s Advanced Program-to-Program Communication (APPC). However, RPC remains a significant technology, particularly in Windows-based environments and heterogeneous networks that include systems like Unix and Apple, as highlighted by Microsoft’s documentation on RPC for creating distributed client/server programs.
