What kind of calls are RPCs typically associated with?

Remote Procedure Calls (RPCs) are primarily associated with synchronous communication. In a typical RPC scenario, when a client makes a request to a server, it waits for the server to process the request and respond before proceeding with further operations. This synchronous behavior simplifies the programming model, as the client can directly use the results of the server's processing immediately after the call returns.

While there are mechanisms to implement asynchronous RPCs, the classical and most common usage of RPC involves a direct, blocking call where the client is halted until the server completes its task and returns the response. This characteristic sets RPCs apart in contrast to purely asynchronous communication methods, where the client may continue its processing without waiting for the server’s response.

Therefore, associating RPCs primarily with synchronous calls accurately reflects their traditional and most prevalent use case.