Remote procedure call
- 1. REMOTE PROCEDURE CALL NAME:- MANOJ PARIHAR SCHOOL:- SITAICS - M.TECH CS RASHTRIYA RAKSHA UNIVERSITY
- 2. INTRODUCTION ● Remote Procedure Call (RPC) is a high-level model for client-server communication. ● A remote procedure call is an interprocess communication technique that is used for client- server based applications. It is also known as a subroutine call or a function call.
- 3. INTRODUCTION ● A client has a request message that the RPC translates and sends to the server. This request may be a procedure or a function call to a remote server. When the server receives the request, it sends the required response back to the client. The client is blocked while the server is processing the call and only resumed execution after the server is finished. ● Examples: File service, Authentication service.
- 4. INTRODUCTION ❖ Why we need Remote Procedure Call (RPC)? ● The client needs a easy way to call the procedures of the server to get some services. ● RPC enables clients to communicate with servers by calling procedures in a similar way to the conventional use of procedure calls in high-level languages. ● RPC is modeled on the local procedure call, but the called procedure is executed in a different process and usually a different computer.
- 5. INTRODUCTION ❖ How to operate RPC? ● When a process on machine A calls a procedure on machine B, the calling process on A is suspended, and the execution of the called procedure takes place on B. ● Information can be transported from the caller to the callee in the parameters and can come back in the procedure result. ● No message passing or I/O at all is visible to the programmer.
- 6. TYPES OF RPC ❖ Three types of RPC are: ➔ Callback RPC ➔ Broadcast RPC ➔ Batch-mode RPC
- 7. CALLBACK RPC ➔ This type of RPC enables a P2P paradigm between participating processes. It helps a process to be both client and server services.
- 8. FUNCTIONS OF CALLBACK RPC: ★ Remotely processed interactive application problems ★ Offers server with clients handle ★ Callback makes the client process wait ★ Manage callback deadlocks ★ It facilitates a peer-to-Peer paradigm among participating processes.
- 9. BROADCAST RPC ➔ Broadcast RPC is a client’s request, that is broadcast on the network, processed by all servers which have the method for processing that request.
- 10. FUNCTIONS OF BROADCAST RPC: ★ Allows you to specify that the client’s request message has to be broadcasted. ★ You can declare broadcast ports. ★ It helps to reduce the load on the physical network.
- 11. BATCH-MODE RPC ➔ Batch-mode RPC helps to queue, separate RPC requests, in a transmission buffer, on the client-side, and then send them on a network in one batch to the server.
- 12. FUNCTIONS OF BATCH-MODE RPC: ★ It minimizes overhead involved in sending a request as it sends them over the network in one batch to the server. ★ This type of RPC protocol is only efficient for the application that needs lower call rates. ★ It needs a reliable transmission protocol.
- 13. THE RPC MODEL
- 14. DESIGN ISSUES ★ Exception handling ➔ Necessary because of possibility of network and nodes failures; ➔ RPC uses return value to indicate errors; ★ Transparency ➔ Syntactic - achievable, exactly the same syntax as a local procedure call. ➔ Semantic - impossible because of RPC limitation: failure (similar but not exactly the same).
- 15. RPC MECHANISM ● Based on concepts of stubs ● Stub is a code used for converting parameter used in procedure call ● RPC involves Client & Server Process ★ Mechanism involves following five elements: ❏ The Client ❏ The Client Stub ❏ The RPCRuntime ❏ The Server Stub ❏ The Server
- 16. RPC MECHANISM
- 17. Steps of a Remote Procedure Call ➢ Client procedure calls client stub in normal way ➢ Client stub builds message, calls local OS ➢ Client's OS sends message to remote OS ➢ Remote OS gives message to server stub ➢ Server stub unpacks parameters, calls server ➢ Server does work, returns result to the stub ➢ Server stub packs it in message, calls local OS ➢ Server's OS sends message to client's OS ➢ Client's OS gives message to client stub ➢ Stub unpacks result, returns to client
- 18. ★ Client: ➢ Initiates RPC ➢ Makes a local call that invokes a corresponding procedure in the client stub ★ Client Stub: 1. Receiving a call request from client: ➢ Packs the specification of the target procedure & the arguments into a message ➢ Asks local RPCRuntime to send it to server stub 1. Receiving result of procedure execution ➢ Unpacks the result & passes it to the client
- 19. RPCRuntime: ★ Client Machine 1. Receive call request message from Client Stub & sends to server machine 2. Receives the message containing the result of procedure execution from the server machine & sends to client stub ★ Server Machine 1. Receives the message containing the result of procedure execution from the server stub & sends it to client machine 2. Receive call request message from the client machine & sends it to server stub
- 20. ★ Server Stub: 1. Receiving a call request from local RPCRuntime: ● Unpacks & makes a normal call to invoke the appropriate procedure in Server ● Receiving result of procedure execution I. Packs the result into a message II. Asks local RPCRuntime to send it to client stub
- 21. ★ Server: 1. Receiving a call request from the server stub ● Executes the appropriate procedure ● Returns the result of execution to the server stub
- 22. STUB GENERATION ★ Manually 1. The RPC implementor provides a set of translation functions from which a user can construct his/her own stubs 2. It is simple to implement and can handle very complex parameter types ★ Automatically 1. Uses Interface Definition Language(IDL)
- 23. MARSHALING ARGUMENTS & RESULT ❏ The transfer of message data between two computers requires encoding & decoding of the message data ❏ This operation in RPCs is known as Marshaling ➔ Actions involved in Marshaling 1. Taking the arguments 2. Encoding the message data on sender’s computer 3. Decoding the message data on receiver’s computer
- 24. CHARACTERISTICS ★ The called procedure is in another process which may reside in another machine. ★ The processes do not share address space. ★ Parameters are passed by values.
- 25. CHARACTERISTICS ★ The called remote procedure executes within the environment of the server process. 1. The called procedure does not have access to the calling procedure environment.
- 26. FEATURES ➔ Simple call syntax ➔ Familiar semantics ➔ Well defined interface ➔ Ease of use ➔ Efficient Can communicate between processes on the same machine or different machines
- 27. ADVANTAGE OF REMOTE PROCEDURE CALL Some of the advantages of RPC are as follows − ➔ Remote procedure calls support process oriented and thread oriented models. ➔ The internal message passing mechanism of RPC is hidden from the user. ➔ The effort to re-write and re-develop the code is minimum in remote procedure calls.
- 28. ADVANTAGE OF REMOTE PROCEDURE CALL ➔ Remote procedure calls can be used in distributed environment as well as the local environment. ➔ Many of the protocol layers are omitted by RPC to improve performance.
- 29. DISADVANTAGE OF REMOTE PROCEDURE CALL Some of the disadvantages of RPC are as follows − ➔ The remote procedure call is a concept that can be implemented in different ways. It is not a standard. ➔ There is no flexibility in RPC for hardware architecture. It is only interaction based. ➔ There is an increase in costs because of remote procedure call.
- 30. ● PROGRAMMING ● CLOUD ● DEVOPS APPLICATION WHERE RPC IS USE
- 31. THANK YOU