A distributed system is a collection of computational and storage devices connected through a communications network. In this type of system, data, software, and users are distributed.

1. DISTRIBUTED
SYSTEM
ARCHITECRURE

2. DISTRIBUTED SYSTEM
 A distributed system is a collection of
computational and storage devices connected
through a communications network. In this
type of system, data, software, and users are
distributed.

3. Example

4. Broker architecture pattern
INTRODUCTION:
 Used to structure the distributed software.
 Responsible for coordinating the
communications
 Forwarding of request from clients.
 Transmission of results and exceptional
 A broker can either be invocation-oriented Or
message /documents oriented.

5. Example

6. Broker ERD

7. Broker Work’s
 Coordination communication
 Controls and interact with client/servers
components
 Maintain the connection between the client
and server

8. Broker architecture components
Invoked six types of components
Clients:
request services of server from broker
Servers:
register and publish client’s interfaces with the
brokers
Brokers
The broker provides APIs for clients to request,
 servers to respond, registering or unregistering server
components, transferring messages, and locating
servers.

9. Components
Bridges :
Optional components used for hiding implementation
details when two brokers interoperate
 They can translate requests and parameters from one
format to another. A bridge can connect two different
networks base on different communication protocols.
Stub (client-side proxy):
 mediates between the client and the broker and provides
additional transparency between them marshals
parameter values, and unmarshals results from the
server

10. Skeleton (server-side proxy):
 mediate between the server and the broker.
 It receives and unpacks the requests,
unmarshals the method arguments, and calls
the appropriate service.

14. Advantages:
 Changeability and extensibility
 Simplicity for clients to access server and
server portability
 Interoperability via broker bridges
 Reusability
Disadvantages:
 Inefficiency due to the overhead of proxies

15. CORBA(Common Object Request
Broker Architecture)

16. RPC (remote Procedure Call)

18. Problems with distributed
system
 Language dependency
 Platform dependency

19. Solution is CORBA
 Provides language independency
 Platform independency.
 A specification or standard which specifies how
objects communicate with each other over a
network.
 It is an middle ware base architecture.
 The ORB(object request broker )is the heart of
distributed component architecture.
 Allow the developers to define the distributed
component architectures without worrying about
the underlying network communication and
programming language.

21. Architecture of CORBA

22. Example of CORBA
This example illustrates the basic tasks in
building a CORBA distributed application using
Java IDL. You will build the classic Hello World
program as a distributed application. The Hello
World program has a single operation that
returns a string to be printed.

23. 1.The client invokes the sayHello method of the HelloServer.
2.The ORB transfers that invocation to the servant object
registered for that IDL interface.
3.The servant's sayHello method runs, returning a Java String.
4.The ORB transfers that String back to the client.
5.The client prints the value of the String.

24. IMPLEMENTATION

25. Message broker Architecture

26. Advantages:
• Reusability and maintainability: Loose
coupling between the client and server
component leads to easy maintenance and
extension on both sides.
• Flexibility: Invocation-oriented or document-
oriented messaging; message heading and body
can be altered for specific purposes.
Disadvantages:
• Overhead, indirection complexity, and difficulty
in debugging and testing due to the new protocol
stack added

27. SERVICE ORIENTED
ARCHITECTURE
(SOA)
 A service-oriented architecture is essentially a
collection of services.
 These services communicate with each other.
The communication can involve either simple
data passing or it could involve two or more
services coordinating some activity. Some
means of connecting services to each other is
needed.

28. Web services
 The technology of Web Services is the most
likely connection technology of service-
oriented architectures.
 The two key specification standards for web
service architecture are the Simple Object
Access Protocol (SOAP) and the Web
Services Description Language (WSDL).

30. SOAP
 SOAP essentially provides the envelope for
sending the Web Services messages.
 A SOAP message is an XML-based document
that is independent of any platform and thus
can be transported by many protocols, such
as HTTP or SMTP.
 service protocol, which can deliver requests
and responses between services loosely. A
connection can be established statically or
dynamically.

31. CASE STUDY

32. Google
 Mission statement “to organize the world’s
information and make it universally accessible
and useful”
 Born out of an internet search research
project at Stanford, now diversified into cloud
computing
 Provide the cloud services

33. Cloud services
software as a service – Google apps includes Gmail,
Google Docs, Google Calendar etc.
platform as a service
offer distributed system application programming interface
(API): protocol used as an interface by software
components to communicate with each other
– e.g. organizations can use this to develop there own
Google Apps.

34. Middleware
 software providing services to software
applications, beyond that provided by the
operating system
 software layer between the O/S and
applications on each side of a distributed
computing system in a network – e.g. the
dash in “client-server”

35. Remote procedure calls

36. RPC

37. RPC

38. GOOGLE FILE SYSTEM

39. Google File System

40. Google file System