Introduction of Computer Networking Technoloy


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  • Ephemeral - impermanent
  • Seamless communication – communication without connection (tanpasambungan)
  • 1x27 1x23+1x21+1x20 1x21+1x20 1x24+1x23+1x22+1x21+1x20
  • Introduction of Computer Networking Technoloy

    1. 1. MTN 2013Computer Network Technology Chapter 1 Introduction
    2. 2. Part I
    3. 3. Outline1. Communication Concept2. Data Communications3. Computer and Data Communications4. Component of Communication Data System11/17/2011 MTN 2013 3
    4. 4. 1. Communication Concept 411/17/2011 MTN 2013
    5. 5. • Communication – exchange of information between two humans• Data communication - exchange of information between two computers11/17/2011 MTN 2013 5
    6. 6. 2. Data CommunicationWhat is data communication?Data communication is subset of telecommunication.Telecommunication - Any process that permits the passage froma sender to one or more receivers of information of any nature,delivered in any easy to use form by any electromagnetic system Data Communication Telecommunication11/17/2011 MTN 2013 6
    7. 7. History of Telecommunications• Invention of telegraph Samuel Morse – 1837• Invention of telephone- Alexander Graham Bell – 1876• Development of wireless by Guglielmo Marconi (develops the first wireless telegraph system) – 1896• Concept of universal access and growth of AT&T• Divestiture of AT&T— 1980s11/17/2011 MTN 2013 7
    8. 8. History of Telecommunications ..continued• Telecommunications Act of 1996• Three main developments that led to the growth of data communications systems: – Large-scale integration of circuits reduced the cost and size of terminals and comm equipment – Developments of software systems made establishment of communication networks easy – Competition among providers of transmission facilities reduced the cost of data circuits11/17/2011 MTN 2013 8
    9. 9. Not to be confused with telecommunication—Data communication -Defined as a subset of telecommunication involving thetransmission of data to and from computers andcomponents of computer systems>> Focus is on the transmission medium, different signal levelsand data coding>> More specifically data communication is transmitted viamediums such as wires, coaxial cables, fiber optics, or radiatedelectromagnetic waves such as broadcast radio, infrared light,microwaves, and satellites11/17/2011 MTN 2013 9
    10. 10. History of Data Communication• Transistor developed by Bell Labs in 1947• Hush-a-Phone Case• Carter phone case• MCI and Long Distance• Creation of networks (LAN’s and WAN’s)• Data Link Protocols• Microcomputers11/17/2011 MTN 2013 10
    11. 11. 3. Computer & Data Communications• Data communications involves the exchange of data between two computers• Computers work with a binary language consisting of zero and one (0 and 1)• Therefore, a computer generates a stream of zeroes and ones and send it to another computer to which it is connected• The connection can be either a simple wire or can be through wireless media• It is not necessary for these two computers to be close to each other – different rooms, cities, states, countries, continents• For enabling data communications, a combination of software and hardware is essential 11/17/2011 MTN 2013 11
    12. 12. ..continued• In any data communications system, three characteristics are desired:i. Correct delivery – when sender transmits data for an intended recipient, the data must reach only the intended recipient and not someone elseii. Accurate delivery – the data sent must be received in the same form as the one in which it was sent. There must not be any sort of alterations to it in transitiii. Timely delivery – the data must travel from the sender to receiver in a finite amount of time. The term finite is quite vague, and would depend on the reasons why the data communications is taking place 11/17/2011 MTN 2013 12
    13. 13. ..continued• Two key aspects of data communications:i. Transmission medium – physical path over which data travels from the sender to receiver (e.g. copper wires, coaxial cables, optical fiber or wireless media such as radio waves)ii. Data communications protocols – set of rules and conventions (standard)*We will discuss these two topics in detail later (next chapters)11/17/2011 MTN 2013 13
    14. 14. 4. Component of Communication Data System• Sender• Receiver• Message• Transmission Medium• Protocol11/17/2011 MTN 2013 14
    15. 15. -A set of rules in data -communications Step 1:.. -Information Step 1:.. formal e.g. Step 2:. data Step 2:.. language which is ….. -physical path ….. connected over which data Protocol travels from the Protocol e.g. image, Sender to-Devices that sound, video receiver send the -Devices that messages Message receive e.g. wire, network, the messagee.g. computer, radio waves telephone, e.g. computer, video video camera, camera Transmission Medium telephone Sender Receiver 11/17/2011 MTN 2013 15
    16. 16. Part II
    17. 17. Outline1. Computer Data Network Application2. Data Communication: Data Protocol3. Data Communication: Data Standard11/17/2011 MTN 2013 17
    18. 18. 1. Computer Data Network Application E-mail Searchable Data (Web Sites) E-Commerce News Groups Internet Telephony (VoIP) Video Conferencing Chat Groups Instant Messengers Internet Radio11/17/2011 MTN 2013 18
    19. 19. E-mail• E-mail stands for Electronic Mail• Basically, allow user to compose and exchange message11/17/2011 MTN 2013 19
    20. 20. Searchable Data (Websites)• A collection of related web pages containing images, videos or other digital assets.• Display organization info and medium of communication.• Two categories; a. static & b. dynamic website.11/17/2011 MTN 2013 20
    21. 21. E-commerce• Electronic Commerce (eCommerce or e-comm)• Consists of the buying and selling of products or services over electronic systems such as the Internet and other computer networks.• It also includes the entire online process of developing, marketing, selling, delivering, servicing and paying for products and services.11/17/2011 MTN 2013 21
    22. 22. Newsgroup• A newsgroup is a discussion about a particular subject consisting of notes written to a central Internet site and redistributed through Usenet, a worldwide network of news discussion groups.11/17/2011 MTN 2013 22
    23. 23. Internet Telephony (VoIP)• Communication protocols• Transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet.11/17/2011 MTN 2013 23
    24. 24. Video Conferencing• A set of interactive telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously.11/17/2011 MTN 2013 24
    25. 25. Chat Groups• Need to choose which group to join.11/17/2011 MTN 2013 25
    26. 26. Instant Messengers• A form of real-time direct text-based communication between two or more people using personal computers or other devices, along with shared clients.• More advanced instant messaging software clients also allow enhanced modes of communication, such as live voice or video calling.11/17/2011 MTN 2013 26
    27. 27. Internet Radio• Also known as web radio, net radio, streaming radio, e-radio.• An audio service transmitted via the Internet.11/17/2011 MTN 2013 27
    28. 28. 2. Data Communication: Data Protocol• The Internet started out around 1969 as a kind of science fair project by the U.S. military, and it was known as the ARPANET. That network no longer exists, but various protocols that were invented for it are still in use.• As the Internet user , a basic understanding of what IP, TCP, and UDP, as well as DNS domain names is very important.11/17/2011 MTN 2013 28
    29. 29. Transmission Control Protocol (TCP)11/17/2011 MTN 2013 29
    30. 30. TCP• Transmission Control Protocol/Transfer Control Protocol/Transport Control Protocol• TCP is the most widely used Internet protocol• Transport layer protocol – Transmit the message from server to client – How client can achieve the server – inter-process communication through port protocol11/17/2011 MTN 2013 30
    31. 31. Port Protocol• Port protocol assigned to the process by operating system• There are 216 port (0 till 65535)• 2 set of ports – UDP protocol – TCP protocol11/17/2011 MTN 2013 31
    32. 32. Host /etc/services PORT11/17/2011 MTN 2013 32
    33. 33. Port Protocol• Port well-known (1 – 1023)• For standard services• HTTP [80], SMTP[25], FTP[21, 22], POP3[110], Telnet [23]• Ephemeral port (1024 – 65535)• Dynamically allocated• Assigned to the client process• After the completion of client process, port will be freed11/17/2011 MTN 2013 33
    34. 34. TCP• Provides reliable transmission services• Uses port protocol for addressing process• Applications that depends on reliability for example telnet, http, ftp etc.11/17/2011 MTN 2013 34
    35. 35. TCP Header Format11/17/2011 MTN 2013 35
    36. 36. TCP Connection• TCP connection has been identified with the end point (port number) of the connection• To establish the TCP connection, it comprise the two ways communication• Client will make a request to the port at the server• Server will open the port and start the connection11/17/2011 MTN 2013 36
    37. 37. Three-way Handshake – Initiate TCP Connection• TCP uses a three-way handshake to initiate the connection for reliability.1. Host A sends a TCP SYNchronize packet to Host BHost B receives As SYN2. Host B sends a SYNchronize-ACKnowledgementHost A receives Bs SYN-ACK3. Host A sends ACKnowledgeHost B receives ACK.TCP socket connection is ESTABLISHED.• TCP Three Way Handshake (SYN,SYN-ACK,ACK)• To make sure both nodes ready to adjust random sequence number for synchronization.11/17/2011 MTN 2013 37
    38. 38. Three-way Handshake11/17/2011 MTN 2013 38
    39. 39. Four-way Handshake - End the TCP Connection• TCP use FIN segment to end the connection• Four-way Handshake MTN 201311/17/2011 39
    40. 40. User Datagram Protocol (UDP)11/17/2011 MTN 2013 40
    41. 41. UDP • Transport layer protocol • Provides communication for unreliable connection • Packet might be lost or not in sequence • No buffer – receive data from application and directly send it. • Has been used when no error control needed. • For the process like; DNS [53], echo [7], tftp [69], SNMP[161]11/17/2011 MTN 2013 41
    42. 42. UDP Datagram Format• Header – UDP Source Port (16 bit) – UDP Destination Port (16 bit) – UDP Message Length (16 bit) – UDP Checksum (16 bit)• Data UDP Source Port UDP Destination Port UDP Message Length UDP Checksum Data MTN 201311/17/2011 42
    43. 43. Internet Protocol (IP)11/17/2011 MTN 2013 43
    44. 44. IP• Network layer protocol• Provides packet transmission through seamless communication.• Use IP address for addressing• Determine packet route through one ore more hop• Provides mechanism consist of: – Data unit (IP datagram) – Software to transmit datagram – Tips on how the computer host process the datagram11/17/2011 MTN 2013 44
    45. 45. Figure 19.2 Links in an internetwork11/17/2011 MTN 2013 45
    46. 46. IP • IP is responsible to provide best-effort transmission for packet/datagram • How the communication through Internet ? – Transport layer take the flow of data and break it to datagram – Network layer transmits each datagram through Internet. Splitting to the smaller unit might happen during this process – At the destination, datagram will be assemble by network layer d to the original datagram and will be sent to transport layer.11/17/2011 MTN 2013 46
    47. 47. Figure 19.4 Network layer at the source11/17/2011 MTN 2013 47
    48. 48. Figure 19.5 Network layer at a router11/17/2011 MTN 2013 48
    49. 49. Figure 19.6 Network layer at the destination11/17/2011 MTN 2013 49
    50. 50. Addressing• Need standard address format• Address format should not rely on hardware address format• Address must be unique in the whole network (Internet)• The body that control address registration – Internet Information Center (InterNIC)11/17/2011 MTN 2013 50
    51. 51. IP Address (IPv4)• Represent by 32-bits integer• Use dotted decimal quad notation – Consists of 4 parts of 8 bits – Separated by full stops MTN 201311/17/2011 51
    52. 52. Network Class• IP address has been organized based on network class – Class A: 0nnnnnnn.iiiiiiii.iiiiiiii.iiiiiiii – Class B: 10nnnnnn.nnnnnnnn.iiiiiiii.iiiiiiii – Class C: 110nnnnn.nnnnnnnn.nnnnnnnn.iiiiiiii – Class D: 1110bbbb.bbbbbbbb.bbbbbbbb.bbbbbbbb – Class E: for future use• Representation: – n – network number – i – host number – b – group id11/17/2011 MTN 2013 52
    53. 53. Address Range to Identify Address Class11/17/2011 MTN 2013 53
    54. 54. • Each IP address has been divided into two parts – Network number(prefix) – shows physical network to where the computer connected – Host number(suffix) – shows computer unique number in network • Internet Corporation for Assigned Names and Numbers (ICANN) responsibles to assign class A, B and C to organization.11/17/2011 MTN 2013 54
    55. 55. • Class A, B and C are the primary class – Use for normal host addressing • Class D for multicast purpose, – to broadcast message • Class E reserved for future use • Each host has virtual address interface known as loopback interface that is – Also known as localhost11/17/2011 MTN 2013 55
    56. 56. Figure 19.19 A network with two levels of hierarchy11/17/2011 MTN 2013 56
    57. 57. IP Address Weakness• Some hosts have more than one IP address• Network classes are too rigid• There was not enough IP address for future use.11/17/2011 MTN 2013 57
    58. 58. Subnet• IP address has been organized as subnet to simplify network management.• Each subnet is address set determined by – Subnet address (example: – Subnet mask (example: MTN 2013 58
    59. 59. Subnet A campus network consists of LAN for the departments MTN 201311/17/2011 59
    60. 60. Figure 19.20 A network with three levels of hierarchy (subnetted)11/17/2011 MTN 2013 60
    61. 61. Figure 19.21 Addresses in a network with and without subnetting11/17/2011 MTN 2013 61
    62. 62. Example of Subnet For class B network: • 3 bits have been used as subnet to become 15 subnet – subnet mask: • The other 13 bits represent host MTN 201311/17/2011 62
    63. 63. Routing• If destination host not in the same network, datagram will be sent to gateway.• How IP choose route to transmit the datagram to a remote network? – By using routing table which has the information on the next hop – other nodes directly connected to the gateway.11/17/2011 MTN 2013 63
    64. 64. Example of Routing Table netstat -nr$ netstat -nrRouting Table: IPv4 Destination Gateway Flags Ref Use Interface-------------------- -------------------- ----- ----- ------ --------- U 1 25591 hme0224.0.0.0 U 1 0 hme0default UG 1 80525127.0.0.1 UH 3 137862 lo0 MTN 201311/17/2011 64
    65. 65. Figure 19.31 Default routing11/17/2011 MTN 2013 65
    66. 66. Internet Protocol Version 6 (IPv6)• Known as Next Generation Internet Protocol (IPng)• Length of the address has been added to 128 bits• Allow additional hosts on the Internet web• Allow the development of Internet11/17/2011 MTN 2013 66
    67. 67. Diagnostic Tools• ping – test connection to host – measure round trip time• traceroute (at microsoft: tracert) – Show the data route from host to destination –• netstat -nr – Show routing table11/17/2011 MTN 2013 67
    68. 68. Diagnostic Tools• ipconfig (at microsoft)• ifconfig -a (at *nix) – Show IP number, subnet and computer gateway11/17/2011 MTN 2013 68
    69. 69. Domain Name System (DNS)11/17/2011 MTN 2013 69
    70. 70. DNS• DNS is a name and address database• It is difficult for human to remember the IP address• DNS provides translation between symbolic name and IP address.• Symbolic name consist of, sequence of alphanumeric component which has been separated by full stop. – example: ,• Name hierarchy: – The far right shows the domain (example: – The far left shows the computer name (example: sun1, www)11/17/2011 MTN 2013 70
    71. 71. Domain Name• The top domain name was determined – example: com, net, org, my• Company buy the name from InterNIC and sell it to other company.11/17/2011 MTN 2013 71
    72. 72. 11/17/2011 MTN 2013 72Chapter 12: The Internet 72
    73. 73. Name Mapping and IP Address• An application program call the library procedure (resolver), by sending the host name as parameter.• Resolver send the UDP packet to local DNS server• The server find the name and return the IP address to resolver, and then to the caller.• With the IP address, program can then make a TCP connection to destination.11/17/2011 MTN 2013 73
    74. 74. 11/17/2011 MTN 2013 74
    75. 75. Tools• hostname – The name of computer• domainname – Name of domain• nslookup – Network and Server Information Tools from Myloca (Telekom Malaysia) MTN 2013 75
    76. 76. 3. Data Communication: Data Standard Layer Common Standards 5. Application layer HTTP, HTML (Web) MPEG, H.323 (audio/video) IMAP, POP (e-mail) 4. Transport layer TCP (Internet) SPX (Novell LANs) 3. Network layer IP (Internet) IPX (Novell LANs) 2. Data link layer Ethernet (LAN) PPP (dial-up via modem) 1. Physical layer RS-232c cable (LAN) Category 5 twisted pair (LAN) V.92 (56 kbps modem)11/17/2011 MTN 2013 76
    77. 77. END Q&A