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Computer Networks

Computer Networks. Why Computer Networks ?. Sharing Resources Sharing Data & Software Efficient Communication Using one database Saving time. Disadvantages of a Computer Networks. High cost to establish Spreading virus soon Need experts to maintain the network

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Computer Networks

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  1. Computer Networks

  2. Why Computer Networks ? • Sharing Resources • Sharing Data & Software • Efficient Communication • Using one database • Saving time

  3. Disadvantages of a Computer Networks • High cost to establish • Spreading virus soon • Need experts to maintain the network • Server down effect the whole network

  4. Aims of a Computer Networks • Resource Sharing • Remote Computability • High Reliability • Ensure the data consistency • Message Passing • Data Security • Save money

  5. Classification Of Network By Geographical Setup • Wide Area Network – (WAN) Spread to unlimited area Eg:- Internet

  6. Classification Of Network By Geographical Setup • Metropolitan Area Network – (MAN) Spread in a City or Country Eg:- Network within town

  7. Classification Of Network By Geographical Setup • Campus Area Network – (CAN) Spread in a site like School, Campus Eg:- Network within a school

  8. Classification Of Network By Geographical Setup • Local Area Network – (LAN) Spread in a Building Eg:- Network within a Building

  9. Classification Of Network By Geographical Setup • Home Area Network – (HAN) Spread in a House Eg:- Network within a home

  10. Classification Of Network By Geographical Setup • Personal Area Network – (PAN) Computer and its components

  11. Classification Of Network By Functional Relationship • Client Sever Clients work under Server

  12. Classification Of Network By Functional Relationship • Peer to Peer (P2P) All the Computer have same capabilities

  13. Classification Of Network By Network Topology • Bus Network

  14. Classification Of Network By Network Topology • Star Network

  15. Classification Of Network By Network Topology • Ring Network

  16. Classification Of Network By Network Topology • Tree Network

  17. Classification Of Network By Network Topology • Mesh Network

  18. Classification Of Network By Network Topology • Hybrid Network

  19. Common Network Elements Server –Manages all the other computers in the network.. Client –Work under the server Communication Media– Trough which computers are connected. Network Operating System (NOS) – Software installed to the server Shared Resources – Devices shared among network clients Modem – Device used to get the internet Hub/ Switch – Device used to connect all the computer

  20. Common Network Elements Server Modem Shared Resources Network Operating Communication Media Clients Hub/ Switch

  21. Hub Hub Vs Switch Switch A B C D Hub sends messages to all computers Switch sends messages to destination computer only

  22. Line Connections 1. Dedicated Line 2. Lease Line 3. Switch line (Dial Up connection)

  23. Transmission Modes Simplex Half Duplex Duplex

  24. Communication Media Guided Media Radiated Media

  25. Guided Media

  26. Guided Media Coaxial Cables

  27. Guided Media Twisted pair cables

  28. Guided Media Fiber Optic Cables

  29. Radiated Media

  30. Radiated Media Media Radio Transmission

  31. Radiated Media Media Infrared Transmission

  32. Radiated Media Media Microwave Transmission

  33. Radiated Media Media Satellite Transmission

  34. Data Transmission Types Serial Transmission 0 1 1 0 0 0 Parallel Transmission 0 1 1 0

  35. Network Interface Card Make the physical Connection between the computer and network wire

  36. What is a Network Protocol ? It is an agreement on transferring Data between computers in a network Eg:- TCP/IP, IPX/SPX, X.25

  37. Backbone Network Components Components that several networks link together. Devices TCP/IP TCP/IP Hub Bridge

  38. Backbone Network Components Components that several networks link together. Devices TCP/IP IPX/SPX Router Gateway

  39. Internet Wide Network spread all over the world to transfer electronic data.

  40. Today Internet is used for…. Business, Education, communication

  41. Resources in the internet Information, Pictures, Sounds, Vedio, on line exams, Games, Chatting

  42. Necessaries for Getting Internet A Computer, Modem, Telephone line, internet browser

  43. Why a modem is needed…. To convert digital signals Analog and vise versa Analog Signals DAC - Modulation Digital Signals ADC - Demodulation

  44. Internet Browsers The Application Software through which we access to the internet Eg :- Internet explorer Netscape Navigator Fire Fox Safari

  45. World Wide Web (WWW) Collection of Web pages throughout the world www.Rupavahini.lk WWW. Rupavahini.lk WWW. Defence.lk

  46. Web Address = URL (Uniform Resource Locator) It is essential to separate web pages each other http: // WWW. Defence.lk /News Protocol Hyper Text Transfer Protocol The server Where this information is? Path name Location of an item on the server

  47. Domain Name www.Rupavahini.lk www.Youtube.com www.Wickipedia.org www. Carrer.edu Classification of web sites according to their contents.

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