Computer networks and various layers in osi.pptx

Computer Networks

1. DISCOVER . LEARN . EMPOWER University Institute of Engineering DEPARTMENT OF COMPUTER SCIENCE & ENGINEERING Bachelor of Engineering (Computer Science & Engineering) Subject Name: Computer Network Subject Code: CSH-312 Prepared By : Er . Monika(E9911)

2. Syllabus UNIT-I Introduction: Introduction to network, Network Categories: LAN, MAN, WAN (Wireless /Wired) , Concept of Layers, Protocols, interfaces and services. Reference Models: OSI, TCP/IP and comparison, Concept of Topologies & its Types Physical Layer: Bit rate, Baud rate, Bandwidth, Transmission Impairments: Attenuation, Distortion, Network Devices-Hub, Switch, Router, Bridge etc. Transmission Media and Switching: Twisted pair, coaxial, fiber optics, Wireless Transmission (radio, microwave & infrared) ;Message switching, Circuit Switching & Packet Switching . UNIT-II Data Link Layer(Flow and Error Control): Design issues , Error Detection & Correction; Flow control & Error Control; Sliding Window Protocols, ARQ: Stop & Wait , Go Back n, Selective Repeat, Examples of DLL protocols – HDLC, PPP. Data Link Layer ( Medium Access Sub layer) Channel Allocation; Random Access: ALOHA, CSMA protocols; Controlled Access: Polling, Reservation, Token Passing Network Layer: Design Issues, IP Addressing – Classless and Class full Addressing. Sub-netting. Super Netting,IPv4 & IPv6; Packet Formats & their comparison, Routing algorithms-optimality principle, shortest path, flooding, Distance Vector Routing, Link State routing etc. UNIT-III Network Layer (Continue): Congestion Control: Principles of congestion control; Congestion prevention policies, Leaky bucket & Token Bucket Algorithms. Transport Layer: Services provided to upper layers, Elements of Transport protocols. Addressing, Flow Control & buffering; Example Transport protocols: TCP & UDP. Application Layer and Network Security : Domain Name System, Simple Network Management Protocol, Electronic Mail, File Transfer Protocol (FTP), HTTP as an application layer protocol. World Wide Web, Basics of authentication, Public and Private Key Cryptography, Digital Signatures and Certificates, Firewalls 2

3. 1. 3 Chapter 1 Introduction

4. 1. 4 1-1 DATA COMMUNICATIONS The term telecommunication means communication at a distance. The word data refers to information presented in whatever form is agreed upon by the parties creating and using the data. Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. Components Data Representation Data Flow Topics discussed in this section:

5. 1. 5 Figure 1.1 Five components of data communication

6. 1. 6 Figure 1.2 Data flow (simplex, half-duplex, and full-duplex)

7. 1. 7 1-2 NETWORKS A network is a set of devices (often referred to as nodes ) connected by communication links . A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network. Distributed Processing Network Criteria Physical Structures Network Models Categories of Networks Interconnection of Networks: Internetwork Topics discussed in this section:

8. 1. 8 Figure 1.3 Types of connections: point-to-point and multipoint

9. 1. 9 Figure 1.4 Categories of topology

10. 1. 10 Figure 1.5 A fully connected mesh topology (five devices)

11. 1. 11 Figure 1.6 A star topology connecting four stations

12. 1. 12 Figure 1.7 A bus topology connecting three stations

13. 1. 13 Figure 1.8 A ring topology connecting six stations

14. 1. 14 Figure 1.9 A hybrid topology: a star backbone with three bus networks

15. 1. 15 Figure 1.10 An isolated LAN connecting 12 computers to a hub in a closet

16. Broadcast Networks 16

17. 17 Local Area Networks

18. Wide Area Networks 18

19. Metropolitan Area Networks 19

20. 1. 20 Figure 1.11 WANs: a switched WAN and a point-to-point WAN

21. 1. 21 Figure 1.12 A heterogeneous network made of four WANs and two LANs

22. 1. 22 1-3 THE INTERNET The Internet has revolutionized many aspects of our daily lives. It has affected the way we do business as well as the way we spend our leisure time. The Internet is a communication system that has brought a wealth of information to our fingertips and organized it for our use. A Brief History The Internet Today (ISPs) Topics discussed in this section:

23. 1. 23 Figure 1.13 Hierarchical organization of the Internet

24. 1. 24 1-4 PROTOCOLS AND STANDARDS In this section, we define two widely used terms: protocols and standards . First, we define protocol, which is synonymous with rule. Then we discuss standards, which are agreed-upon rules. Protocols Standards Standards Organizations Internet Standards Topics discussed in this section:

25. Chapter 2 Network Models

26. 2. 26 2-1 LAYERED TASKS We use the concept of layers in our daily life. As an example, let us consider two friends who communicate through postal mail. The process of sending a letter to a friend would be complex if there were no services available from the post office. Sender, Receiver, and Carrier Hierarchy Topics discussed in this section:

27. 2. 27 Figure 2.1 Tasks involved in sending a letter

28. 2. 28 2-2 THE OSI MODEL Established in 1947, the International Standards Organization ( ISO ) is a multinational body dedicated to worldwide agreement on international standards. An ISO standard that covers all aspects of network communications is the Open Systems Interconnection ( OSI ) model. It was first introduced in the late 1970s. Layered Architecture Peer-to-Peer Processes Encapsulation Topics discussed in this section:

29. 2. 29 ISO is the organization. OSI is the model. Note

30. 2. 30 Figure 2.2 Seven layers of the OSI model

31. 2. 31 Figure 2.3 The interaction between layers in the OSI model

32. 2. 32 Figure 2.4 An exchange using the OSI model

33. 2. 33 2-3 LAYERS IN THE OSI MODEL In this section we briefly describe the functions of each layer in the OSI model. Physical Layer Data Link Layer Network Layer Transport Layer Session Layer Presentation Layer Application Layer Topics discussed in this section:

34. 2. 34 Figure 2.5 Physical layer

35. 2. 35 The physical layer is responsible for movements of individual bits from one hop (node) to the next. Note

36. 2. 36 Figure 2.6 Data link layer

37. 2. 37 The data link layer is responsible for moving frames from one hop (node) to the next. Note

38. 2. 38 Figure 2.7 Hop-to-hop delivery

39. 2. 39 Figure 2.8 Network layer

40. 2. 40 The network layer is responsible for the delivery of individual packets from the source host to the destination host. Note

41. 2. 41 Figure 2.9 Source-to-destination delivery

42. 2. 42 Figure 2.10 Transport layer

43. 2. 43 The transport layer is responsible for the delivery of a message from one process to another. Note

44. 2. 44 Figure 2.11 Reliable process-to-process delivery of a message

45. 2. 45 Figure 2.12 Session layer

46. 2. 46 The session layer is responsible for dialog control and synchronization. Note

47. 2. 47 Figure 2.13 Presentation layer

48. 2. 48 The presentation layer is responsible for translation, compression, and encryption. Note

49. 2. 49 Figure 2.14 Application layer

50. 2. 50 The application layer is responsible for providing services to the user. Note

51. 2. 51 Figure 2.15 Summary of layers

52. 2. 52 2-4 TCP/IP PROTOCOL SUITE The layers in the TCP/IP protocol suite do not exactly match those in the OSI model. The original TCP/IP protocol suite was defined as having four layers: host-to-network , internet , transport , and application . However, when TCP/IP is compared to OSI, we can say that the TCP/IP protocol suite is made of five layers: physical , data link , network , transport , and application . Physical and Data Link Layers Network Layer Transport Layer Application Layer Topics discussed in this section:

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55. 2. 55 Figure 2.16 TCP/IP and OSI model

56. References: https://beginnersbook.com/2019/03/computer-network-architecture/ https://www.tutorialspoint.com/data_communication_computer_network/physical_layer_introduction.htm http://highered.mheducation.com/sites/0072967757/student_view0/chapter1/powerpoint_slides.html 56