Lecture 10

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. 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. 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. Face-to-face Communication Message Voice Channel/Medium A short distance of air SenderPerson ReceiverPerson

11. Telecommunications Message Voice, Data Video, etc. SenderTelephone, Computer, Video Conferencing ReceiverTelephone, Computer, Video Conferencing Channel/MediumVarious Types of Electronic Media

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. 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 16

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

39. A Network Router

40. Computer Network Layouts

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

45. Micro computer to LAN Gaming Competition

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. Microcomputer-to-Internet Layout (continued)

48. Dialup Connections

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