CHAPTER - 4 REMOTE COMMUNICATION

Size: px

Start display at page:

Download "CHAPTER - 4 REMOTE COMMUNICATION"

Whitney Loreen Heath
6 years ago
Views:

1 CHAPTER - 4 REMOTE COMMUNICATION

2 Topics Introduction to Remote Communication Remote Procedural Call Basics RPC Implementation RPC Communication Other RPC Issues Case Study: Sun RPC Remote invocation Basics RMI Implementation

3 Introduction to Remote Communication

4 Introduction Middleware

5 Remote Procedural Call Basics

6 Local Procedure Call

7 Remote Procedure Call Basic RPC operation

8 RPC operation

9 Elements of RPC mechanism implementation Client Client stub RPC Runtime Server stub Server

10 RPC Execution

11 Stub generation Manual generation Auto generation using Interface Definition Language (IDL)

12 RPC Compilation

13 RPC Implementation

14 RPC implementation RPC messages: Call / Request Reply

15 RPC Call/ Request message

16 RPC reply conditions

17 RPC reply message

18 Parameter Passing Semantics Call-by-value semantic Marshalling Call-by reference semantic Call-by-copy/restore semantic Call-by-value copies all parameters into a message before transmission. Call-by-reference passes pointers to the parameters that are passed from the client to the server. Call-by-copy/restore uses temporary storage accessible to both programs

19 Call-by-value semantic

20 Byte ordering

21 Server management Server implementation Stateless server Stateful server Server management Instance per call Instance per session Persistent servers

22 RPC communication RPC call semantics

23 Orphan calls Calls whose caller has expired due to a node crash Handle orphan calls by using: Extermination Reincarnation Gentle reincarnation Expiration

24 RPC communication protocols Request protocol Request/Reply protocol Request/Reply/ Acknowledge- Reply protocol

25 Request protocol

26 Asynchronous RPC

27 Request/Reply protocol

28 Request/Reply/ Acknowledge- Reply protocol

29 Client server binding process

30 Client Server binding Issues Server naming Server locating Binding agent primitives Register Deregister Lookup Types of binding Fixed binding Dynamic binding At compile time At link time At run time

31 Other RPC Issues

32 Other issues in RPC implementation Exception handing and security Failure handling Optimizing RPC execution Various types of complicated RPCs

33 RPC in heterogeneous environment Data presentation Transport protocol Control protocol

34 Failure handling mechanism in RPC Client cannot find the server Request from client to the server is lost Reply from server to the client is lost Server crashes after getting the request Client crashes after sending the request

35 RPC Optimization

36 Concurrent access to multiple servers Use of threads Early reply technique Call buffering approach Serving multiple requests simultaneously Reducing call workload of server Using reply cache for idempotent RPC

37 Early Reply technique

38 Call buffer approach

39 Complicated and special RPCs Complicated RPCs RPCs with long duration calls or with gaps between calls RPCs with long messages Special RPCs: Call back RPC Broadcast RPC Batch mode RPC

40 Call back RPC Client handle is provided to the server Client process should wait for callback RPC Handle callback deadlocks

41 Case Study: Sun RPC

42 Case Study- Sun RPC Uses rpcgen compiler which generates Header file XDR filter file Client stub file Server stub file

43 Remote invocation Basics

44 Remote Object Invocation Distributed object concept Remote objects reference Remote interface

45 RMI

46 RMI vs LMI

47 RMI Implementation

48 RMI implementation Design issues in RMI RMI invocation semantics Level of transparency Marshalling Message passing Task of locating and contacting the remote object for the client RMI invocation semantics Maybe semantics At-least-once semantics At-most-once semantics

49 Invocation semantics

50 Level of Transparency

51 Components of RMI

52 RMI execution components Communication module Remote reference module RMI software Server program Client program Binder

53 RMI execution

54 RMI software Proxy Dispatcher Skeleton

55 Types of objects

56 Remote invocation readiness

57 RMI binding Implicit binding Explicit binding

58 Parameter passing in RMI Pass by value Pass by reference

59 Case study: Java RMI

60 Java RMI layer

61 Summary Introduction to Remote Communication Remote Procedural Call Basics RPC Implementation RPC Communication Other RPC Issues Case Study: Sun RPC Remote invocation Basics RMI Implementation

Today CSCI Communication. Communication in Distributed Systems. Communication in Distributed Systems. Remote Procedure Calls (RPC)

Today CSCI Communication. Communication in Distributed Systems. Communication in Distributed Systems. Remote Procedure Calls (RPC) Today CSCI 5105 Communication in Distributed Systems Overview Types Remote Procedure Calls (RPC) Instructor: Abhishek Chandra 2 Communication How do program modules/processes communicate on a single machine?