Communication

1
Communication

• Chapter 2

2
Layered Protocols (1)
2-1

• Layers, interfaces, and protocols in the OSI
  model.

3
Layered Protocols (2)
2-2

• A typical message as it appears on the network.

4
Data Link Layer
2-3

• Discussion between a receiver and a sender in the
  data link layer.

5
Client-Server TCP
2-4

• Normal operation of TCP.
• Transactional TCP.

6
Middleware Protocols
2-5

• An adapted reference model for networked
  communication.

7
Conventional Procedure Call

• Parameter passing in a local procedure call the
  stack before the call to read
• The stack while the called procedure is active

8
Client and Server Stubs

• Principle of RPC between a client and server
  program.

9
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

10
Passing Value Parameters (1)
2-8

• Steps involved in doing remote computation
  through RPC

11
Passing Value Parameters (2)

• Original message on the Pentium
• The message after receipt on the SPARC
• The message after being inverted. The little
  numbers in boxes indicate the address of each byte

12
Parameter Specification and Stub Generation

• A procedure
• The corresponding message.

13
Doors

• The principle of using doors as IPC mechanism.

14
Asynchronous RPC (1)
2-12

• The interconnection between client and server in
  a traditional RPC
• The interaction using asynchronous RPC

15
Asynchronous RPC (2)
2-13

• A client and server interacting through two
  asynchronous RPCs

16
Writing a Client and a Server
2-14

• The steps in writing a client and a server in DCE
  RPC.

17
Binding a Client to a Server
2-15

• Client-to-server binding in DCE.

18
Distributed Objects
2-16

• Common organization of a remote object with
  client-side proxy.

19
Binding a Client to an Object
Distr_object obj_ref //Declare a systemwide
object referenceobj_ref // Initialize the
reference to a distributed objectobj_ref-gt
do_something() // Implicitly bind and invoke a
method (a) Distr_object objPref //Declare a
systemwide object referenceLocal_object
obj_ptr //Declare a pointer to local
objectsobj_ref //Initialize the reference
to a distributed objectobj_ptr
bind(obj_ref) //Explicitly bind and obtain a
pointer to the local proxyobj_ptr -gt
do_something() //Invoke a method on the local
proxy (b)

• (a) Example with implicit binding using only
  global references
• (b) Example with explicit binding using global
  and local references

20
Parameter Passing
2-18

• The situation when passing an object by reference
  or by value.

21
The DCE Distributed-Object Model
2-19

• Distributed dynamic objects in DCE.
• Distributed named objects

22
Persistence and Synchronicity in Communication (1)
2-20

• General organization of a communication system in
  which hosts are connected through a network

23
Persistence and Synchronicity in Communication (2)

• Persistent communication of letters back in the
  days of the Pony Express.

24
Persistence and Synchronicity in Communication (3)
2-22.1

• Persistent asynchronous communication
• Persistent synchronous communication

25
Persistence and Synchronicity in Communication (4)
2-22.2

• Transient asynchronous communication
• Receipt-based transient synchronous communication

26
Persistence and Synchronicity in Communication (5)

• Delivery-based transient synchronous
  communication at message delivery
• Response-based transient synchronous communication

27
Berkeley Sockets (1)

• Socket primitives for TCP/IP.

28
Berkeley Sockets (2)

• Connection-oriented communication pattern using
  sockets.

29
The Message-Passing Interface (MPI)

• Some of the most intuitive message-passing
  primitives of MPI.

30
Message-Queuing Model (1)
2-26

• Four combinations for loosely-coupled
  communications using queues.

31
Message-Queuing Model (2)

• Basic interface to a queue in a message-queuing
  system.

32
General Architecture of a Message-Queuing System
(1)

• The relationship between queue-level
  addressing and network-level addressing.

33
General Architecture of a Message-Queuing System
(2)
2-29

• The general organization of a message-queuing
  system with routers.

34
Message Brokers
2-30

• The general organization of a message broker in a
  message-queuing
• system.

35
Example IBM MQSeries
2-31

• General organization of IBM's MQSeries
  message-queuing system.

36
Channels

• Some attributes associated with message channel
  agents.

37
Message Transfer (1)

• The general organization of an MQSeries queuing
  network using routing tables and aliases.

38
Message Transfer (2)

• Primitives available in an IBM MQSeries MQI

39
Data Stream (1)

• Setting up a stream between two processes across
  a network.

40
Data Stream (2)
2-35.2

• Setting up a stream directly between two devices.

41
Data Stream (3)

• An example of multicasting a stream to several
  receivers.

42
Specifying QoS (1)

• A flow specification.

43
Specifying QoS (2)

• The principle of a token bucket algorithm.

44
Setting Up a Stream

• The basic organization of RSVP for resource
  reservation in a distributed
• system.

45
Synchronization Mechanisms (1)

• The principle of explicit synchronization on the
  level data units.

46
Synchronization Mechanisms (2)
2-41

• The principle of synchronization as supported by
  high-level interfaces.