What are RPCs?
Remote Procedure Calls (RPCs) are a fundamental concept in distributed computing, facilitating communication between different processes or systems over a network. They allow programs to invoke procedures or functions on remote systems as if they were local, enabling distributed applications to interact seamlessly.
How RPCs Work
Client-Server Model: RPCs typically follow a client-server model, where a client initiates a request to execute a procedure on a remote server.
Request-Response Protocol: The client sends a request containing the name of the procedure to be executed, along with any required parameters, to the server over the network.
Execution on Server: The server receives the request, executes the specified procedure, and returns the results (if any) to the client.
Synchronous or Asynchronous: RPCs can be synchronous, where the client waits for the server's response before proceeding, or asynchronous, where the client continues execution while waiting for the response.
Components of RPCs
Stub: On the client side, a stub acts as a proxy for the remote procedure. It marshals the request parameters into a format suitable for transmission over the network and sends the request to the server.
Skeleton: On the server side, a skeleton receives the incoming request, unmarshals the parameters, and invokes the actual procedure.
Marshalling and Unmarshalling: Marshalling involves converting the procedure parameters into a format that can be transmitted over the network, while unmarshalling reverses this process on the server side.
Benefits of RPCs
Abstraction of Network Complexity: RPCs abstract the complexities of network communication, allowing developers to focus on application logic rather than low-level networking details.
Interoperability: RPCs enable communication between heterogeneous systems, as long as they adhere to a common RPC protocol.
Encapsulation of Functionality: RPCs encapsulate functionality into reusable components, promoting modular design and code reuse.
Scalability: RPCs facilitate the development of scalable distributed systems by allowing services to be distributed across multiple nodes.
Common Implementations
XML-RPC: Uses XML for message encoding and HTTP for transport, making it platform-independent and widely adopted for web services.
JSON-RPC: Similar to XML-RPC but uses JSON for message encoding, resulting in a more compact and human-readable format.
gRPC: Developed by Google, gRPC is a high-performance RPC framework that uses Protocol Buffers for message encoding and HTTP/2 for transport, offering features such as streaming and bi-directional communication.
CORBA: Common Object Request Broker Architecture (CORBA) is a mature RPC framework that supports multiple programming languages and platforms through its Interface Definition Language (IDL).
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