1. Lecture 10 Introduction to Computer Networks and Data Communications

2. Summary of Previous In the previous lecture we have learnt, Managing business data MS Access 2007  Purpose and Data Organization  Creating a Database Table Form Query Report

3. Summary of Previous Data Presentation  Purpose and Types of presentations  Microsoft Power Point  A New presentation  Design Templates  Animation  Slide Master  Adding Pictures  Working With Text  Graphs and Charts

4. 4 Today’s Topics Introduction to Telecommunications  Basic Components of Communications  Telecommunications Media  Rate of data transfer Define the basic terminology of computer networks  Network Topology  Classification of Computer Networks  Network Devices  Recognize the individual components of the big picture of computer networks

5. Today’s Topics Computer Network Layouts  Microcomputer-to-local area network  Microcomputer-to-Internet  Local area network-to-local area network  Personal area network-to-workstation  Local area network-to-metropolitan area network  Local area network-to-wide area network

6. Today’s Topics  Sensor-to-local area network  Satellite and microwave  Cell phones  Computer terminal / microcomputer-to- mainframe Summary

7. 7 Introduction Everyone is using a computer network today. Mass transit, interstate highways, 24-hour bankers, grocery stores, cable television, cell phones, businesses and schools, and retail outlets support some form of computer network

8. What is Telecommunication? Transmission of different forms of data  such as text, audio, video, images, graphics It occurs between one set of electronic devices over media to another set of geographically separated electronic devices.

9. Basic Components of Communications Sender: Person or device sending the message Receiver: Person or device receiving the message Medium: What carries the message from sender to receiver

10. Sender Person Receiver Person Channel/Medium A short distance of air Message Voice Face-to-face Communication

11. Sender Telephone, Computer, Video Conferencing Channel/Medium Various Types of Electronic Media Message Voice, Data Video, etc. Receiver Telephone, Computer, Video Conferencing Telecommunications

12. Telecommunications Media Communications media - the paths, or physical channels, in a network over which information travels. Wired communications media - transmit information over a closed, connected path. Wireless communications media - transmit information through the air.

13. Telecommunications Media

14. Telecommunication – Rate of data transfer Data transmission channels (bps)  narrow bands: 5-30  voice bands: 1,000-9,600  broad bands: 100,000

15. Computer Networks

16. 16 What is Computer Network? Computer network is an interconnection of computers and computing equipment using either wires or radio waves over small or large geographic areas

17. Network Topology – Connecting Computers The network topology defines the way in which computers, printers, and other devices are connected. A network topology describes the layout of the wire and devices as well as the paths used by data transmissions.

18. Bus Topology  Commonly referred to as a linear bus, all the devices on a bus topology are connected by one single cable.

19. Bus Topology

20. Ring Topology A network configuration in which computers are arranged in the form of a ring using twisted-wire, coaxial cable, or fiber optics. Messages are transmitted in one direction to all devices between the sending node and the receiving node.

21. Ring Topology

22. Star Topology A topology in which a central host computer receives all messages and then forwards the message to the appropriate computer on the network.

23. Star Topology

24. Mesh Topology The mesh topology connects all devices (nodes) to each other for redundancy and fault tolerance. It is used in WANs to interconnect LANs and for mission critical networks like those used by banks and financial institutions. Implementing the mesh topology is expensive and difficult.

25. Classification of Computer Networks

26. Different Types of Network Exists Local area network  Networks that are small in geographic size spanning a room, floor, building, or campus

27. Types Metropolitan area network  Networks that serve an area of 1 to 30 miles, approximately the size of a typical city

28. MAN MAN networks are generally good for businesses and organizations that have multiple locations around a city. A bank may also take advantage of a MAN.

29. Types Wide area network  a large network that encompasses parts of states, multiple states, countries, and the world

30. Types Personal area network  a network of a few meters, between wireless devices such as PDAs, laptops, and similar devices

31. Types Voice network  a network that transmits only telephone signals (almost extinct) Data network  a network that transmits voice and computer data (replacing voice networks)

32. 32 Computer Network Popular Terms Data communications – the transfer of digital or analog data using digital or analog signals Telecommunications – the study of telephones and the systems that transmit telephone signals (becoming simply data communications)

33. Popular Terms Network management – the design, installation, and support of a network, including its hardware and software Network cloud – a network (local or remote) that contains software, applications, and/or data

34. 34 The Big Picture of Networks Networks are composed of many devices, including:  Workstations (computers, tablets, wireless phones, etc)  Servers  Network hubs and switches  Routers (LAN to WAN and WAN to WAN)  Telephone switching gear

35. 35 The Big Picture of Networks (continued)

36. Network Devices Workstations  They are personal computers/microcomputers (desktops, laptops, net books, hand held, etc.) where users reside Servers,  They are the computers that store network software and shared or private user files

37. Network Devices Switches,  They are the collection points for the wires that interconnect the workstations Routers,  They are the connecting devices between local area networks and wide area networks

38. A Switch A Switch with Network Ports RJ-45 and Network Cables

39. A Network Router

40. Computer Network Layouts

41. 41 Basic Layouts of Communication networks Microcomputer-to-local area network Microcomputer-to-Internet Local area network-to-local area network Personal area network-to-workstation Local area network-to-metropolitan area network

42. 42 Local area network-to-wide area network Sensor-to-local area network Satellite and microwave Cell phones Computer terminal / microcomputer-to- mainframe Basic Layouts of Communication networks

43. 43 Highly common throughout business and academic environments, and now homes Typically a medium- to high-speed connection Computer (device) requires a NIC (network interface card) NIC connects to a hub-like device (switch) Micro Computer to Local Area Network Layout

44. 44 Microcomputer-to-Local Area Network Layout (continued)

45. Micro computer to LAN Gaming Competition

46. 46 Microcomputer-to-Internet Layout Popular with home users and small businesses For some, a dial-up modem is used to connect user’s microcomputer to an Internet service provider Technologies such as DSL and cable modems are replacing modems

47. 47 Microcomputer-to-Internet Layout (continued)

48. Dialup Connections

49. 49 Local Area Network-to-Local Area Network Layout Found in systems that have two or more LANs and a need for them to intercommunicate A bridge-like device (such as a switch) is typically used to interconnect LANs

50. 50 Local Area Network-to-Local Area Network Layout (continued) Hardware that connects computers to one another on a local network.

51. 51 Personal Area Network-to-Workstation Layout Interconnects wireless devices such as PDAs, laptops and notebooks, and music playback devices Used over short distances such as a few meters

52. 52 Personal Area Network-to-Workstation Layout (continued)

53. Example

54. 54 Local Area Network-to-Metropolitan Area Network Layout Used to interconnect companies (usually their local area networks) to networks that encompass a city High-speed networks  Typically, this interconnection uses only fiber- optic links

55. 55 Local Area Network-to-Metropolitan Area Network Layout (continued)

56. 56 Local Area Network-to-Wide Area Network Layout One of the most common ways to interconnect a user on a LAN workstation to the Internet (a wide area network) A router is the typical device that performs LAN to WAN connections Routers are more complex devices than switches

57. Data Communications and Computer Networks: A Business User's Approach, Sixth Edition57 Local Area Network-to-Wide Area Network Layout (continued)

58. 58 Wide Area Network-to-Wide Area Network Layout High-speed routers and switches are used to connect one wide area network to another Thousands of wide area networks across Pakistan, many interconnected via these routers and switches

59. 59 Sensor-to-Local Area Network Layout Not all local area networks deal with microcomputer workstations Often found in industrial and laboratory environments Assembly lines and robotic controls depend heavily on sensor-based local area networks

60. 60 Sensor-to-Local Area Network Layout (continued)

61. 61 Satellite and Microwave Layout Typically long distance wireless connections Many types of applications including long distance telephone, television, radio, long-haul data transfers, and wireless data services Typically expensive services but many companies offer competitive services and rates Newer shorter-distance services such as Wi- Max

62. 62 Satellite and Microwave Layout (continued)

63. 63 Cell Phone Layout Expanding market across the world specially Pakistan. Third generation services available in many areas and under many types of plans with fourth generation services starting to appear Latest generation includes higher speed data transfers (100s to 1000s of kilobits per second)

64. 64 Cell Phone Layout (continued)

65. 65 Terminal/Microcomputer-to-Mainframe Computer Layout Predominant form in the 1960s and 1970s Still used in many types of businesses for data entry and data retrieval Few dumb terminals left today, e.g. Telnet

66. 66 Terminal/Microcomputer-to-Mainframe Computer Layout (continued)

67. 67 One More Layout An Additional Basic layout – telephone-to- network  Telephone systems are ubiquitous and now carry more data than voice  Voice over IP – telephone-to-LAN via gateway or telephone to gateway via DSL/cable

68. Summary We have been discussed about  Telecommunication essentials  Computer Networks Definition Topology Classification Layouts We have understood that using network we can perform day to day business functions.  Depending upon the types and nature of business we want to set up our computer network.