Data Structures unit I just look to learn the contents

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1. IT22501 – Data Communication and Networking Introducing the Subject

2. Course Objective • To understand the protocol layering. • To analyze the performance of the Networks. • To understand the various components required to build different networks. • To learn function of a network layer. • To familiarize the functions and protocols of the transport layer.

3. Unit I UNIT I INTRODUCTION AND PHYSICAL LAYER 6 Networks – Network Types – Protocol Layering – TCP/IP Protocol suite – OSI Model – Physical Layer: Performance – Transmission media : Guided media-Unguided media: Wireless– Switching. Unit II UNIT II DATALINK LAYER 6 Introduction-nodes and link-Two types of links-Two sublayers -Data link control: Framing-Error Control-Two DLC protocols – Link-Layer Addressing – DLC Services – Data-Link Layer Protocols – HDLC.

4. Unit III Unit IV UNIT III NETWORK LAYER 6 Network Layer Services: Packetizing-Routing-Error Control-Flow Control-Congestion Control quality of service-Network layer performance: Delay-Throughput-packet loss – Packet switching – Performance – IPV4 Addresses – Forwarding of IP Packets – Network Layer Protocols: IP, ICMP v4. UNIT IV TRANSPORT LAYER 6 Introduction – Transport Layer Protocols: Services – Port Numbers – User Datagram Protocol: UDP services-UDP applications-Transmission control protocol: TCP services-TCP features Segment-A TCP connection-State Transition Diagram-SCTP: SCTP services-SCTP features.

5. Unit V UNIT V APPLICATION LAYER 6 WWW and HTTP – FTP – Email –Telnet-Secure Shell (SSH)-Domain Name System(DNS).

6. COURSE OUTCOMES CO1 Explain the concepts of Data Communication, basic layers and its function in computer networks. CO2 Infer the concepts of datalink layer. CO3 Apply routing algorithms and their functionality. CO4 Apply the working of transport and application layer protocol. CO5 Analyse the performance of TCP and UDP.

7. BOOKS TEXT BOOKS   Behrouz A. Forouzen , “Data Communications and Networking with TCP/IP Protocol Suite”, Sixth Edition, TMH,2022 2.  William Stallings, “Data and Computer Communications”, Eighth Edition, Pearson Education, 2023. REFERENCE BOOKS   Larry Peterson, Bruce S. Davie, “Computer Networks: A system Approach”, Fifth Edition, Morgan Kaufmann Publishers Inc , 2012 2.  Doug Lowe, “Networking all-in one Dummies”, Seventh Edition, Wiley Publication, 2018. 3.  Nader F. Mir, “Computer and Communication Networks”, Second Edition, Prentice hall, 2015. 4.  Ying-Dar Lin, Ren-Hung Hwang and Fred Baker, “Computer Networks: An open Source Approach”, McGraw Hill Publishers, 2011.

8. What is Networking? Lets see a demo video on how data travels in the network…. - VIDEO

9. IT22501 – Data Communication and Networking Unit I – Introduction and Physical Layer

10. Introducing Network Data – Any Information Data Communication – exchange of data – two devices – via transmission medium – supporting software Characteristics of Network: Delivery – to intended device Accuracy – messages cannot be altered or corrected Timeliness – a late data is useless Jitter – variation in packet arrval

11. Components of Data Communication

12. Data Representation Text – 0s and 1s – codes Unicode – 32-bit ASCII – 7-bit Numbers – Images – Audio – Video -

13. UNI CODE

14. ASCII CODE

15. Image to binary form https://www.dcode.fr/binary-image

16. Audio to Binary - https://openl.io/translate/mp3/binary Video to Binary - https://base64.guru/converter/encode/video

17. Data Flow

18. Network Interconnection of communicating devices Host – end system Connecting device – network to network Modem – change the form of data

19. Network criteria Performance – measured with Transit time – time travel of message from one device to another Response time – elapsed time between an inquiry and a response Throughput – volume of data into the network in a time Delay or latency – delay or actual time for communicating a data Reliability – time taken to recover from a failure Security – protecting

20. Physical structures Point-to-point – dedicated b/w 2 devices Multipoint – or multidrop – spatial or temporal

21. Physical topology – Mesh Topology is the way devices are connected to one another In mesh – simplex – n(n-1) - duplex – n(n-1)/2

22. Advantages: Dedicated links Robustness - if one link is unusable, it does not disturb the network or other connections Privacy and security of data is ensured make fault identification and fault isolation easy Disadvantages: huge amount of cabling and IO ports required as there is dedicated connection between every device huge space is required for keeping the connections the hardware requirement makes the installation costly

23. STAR TOPOLOGY dedicated point-to-point link to hub Advantages: It is less expensive than mesh easy to install, configure and less cabling Robust, easy in fault detection and isolation Disadvantages: All the connections depend on hub, failure of hub will fail the entire system. It requires more cabling than ring and bus topology

24. Bus Topology multipoint in which one cable act as a backbone – dropline and taps Advantages: Efficient installation Disadvantages: the main cable travels long, so the signals become weaker and weaker a limit on the number of taps Difficult reconnection and fault isolation Difficult to add new devices as it requires modification and replacement Signal reflection at the taps can cause degradation in quality a fault or break in the bus cable stops all transmission

25. Ring Topology Advantages : Easy to install and reconfigure as each device Fault isolation is simplified Disadvantages: a break in the ring can disable the entire network

26. Network types - LAN Private network at least with 2 or more host Each having an address Packet from one host to another host has both source and destination address LAN uses connecting switches for guiding packets towards destination LAN switch advantages Eliminates traffic Multipoint communication

27. LAN

28. WAN To connect to wider areas Connecting devices Switch Router modems Types Point-to-Point WAN Switched WAN

29. Point-to-point wan Network for two communicating devices

30. Switched wan More than two ends Combination of many point-to-point WAN

31. Internetwork LAN and WAN connected to form internet

32. heterogeneous network made of four WANs and three LANs

33. Internet

34. internet Backbone or ISPs – large network owned by BSNL, starlink etc. and are connected via complex switching system called – peering points Provider networks – uses the service backbone for fee Customer network – edge users

35. Accessing the internet Using telephone networks Dial-up services – add modem to telephone – Computer software for dialing to internet Slow and cant access internet when using phone DSL (digital subscriber line Simultaneous data and voice communication

36. Using cable network TV lines extended for internet Speed varies depending on the users in the same cable

37. Using Wireless Networks WWAN – cellular technology Components Router Cellular network SIM card Cloud management tool

38. DIRECT connection to internet

39. PROTOCOL LAYERING Protocol – rules for sending and receiving devices for effective communication Protocol layering - Layers to split the task for communication Single layered protocol Handshake Bidirectional communication Pre-defined communication language

40. A three-layered protocol Why – communication between different devices

41. Layered architecture - elements Service − Set of actions or services provided from one layer to the higher layer. Protocol − It defines a set of rules where a layer uses to exchange the information with its peer entity. It is concerned about both the contents and order of the messages used. Interface − It is a way through that the message is transferred from one layer to another layer.

42. Reason – Layered Architecture Well-defined interface between layers Feasible implementation Advantages Each layer is assisted with a protocol products from completely different vendors will work along Prevents technology or capability changes typical language to explain networking functions and capabilities Disadvantages: layered systems are the abstraction barriers between layers The upper-level layers cannot see what is within the lower layers i.e. no connections can be made The higher-level layers cannot control all aspects of the lower layers

43. the layers are layered there remains a logical connection

44. TCP/IP Protocol suite TCP/IP (Transmission Control Protocol/Internet Protocol ) suite Five layered architecture Upper level may be interactive with lower layers

45. Basic Elements of Layered Architecture Service − Set of actions or services provided from one layer to the higher layer. Protocol − It defines a set of rules where a layer uses to exchange the information with its peer entity. It is concerned about both the contents and order of the messages used. Interface − It is a way through that the message is transferred from one layer to another layer.

46. Reason for Layering well-defined interfaces between the layers designing them in layers makes their implementation more feasible Advantages: a defined interface to the layers products from completely different vendors will work along Prevents technology or capability changes a typical language to explain networking functions and capabilities

47. Disadvantages: layered systems are the abstraction barriers between layers The upper-level layers cannot see what is within the lower layers The higher-level layers cannot control all aspects of the lower layers

48. duty of the top three layers is the internet, and the domain of duty of the two lower layers is the link data-link and physical layers is hop-to-hop Top three – packets are not changed Bottom two layers – packets are changed

49. TCP/IP suite Layer Description Physical Layer – is the lowest level and is for carrying individual bits in a frame across the link. o the communication between two devices at the physical layer is still a logical communication because there is another hidden layer, the transmission media, under the physical layer. Data-link Layer – is responsible for taking the datagram and moving it across the link. o An internet is made up of several links (LANs and WANs) connected by routers that determines the next link to be travelled.

50. Network Layer – is for creating a connection between the source and destination computers and is a host-to-host communication. o The routers in the path chooses the best route for each packet. Transport Layer – has a logical end-to-end connection between the hosts. o At the source it gets the message from the application layer; encapsulates it in a transport-layer packet (called a segment or a user datagram in different protocols); and sends it, through the logical (imaginary) connection, to the transport layer at the destination host. o i.e., the transport layer is responsible for giving services to the application layer: to get a message from an application program running on the source host and deliver it to the corresponding application program on the destination host.

51. Application Layer – also has the logical end-to-end connection i.e., is a process-to-process communication. o Though the communication is done through all layers, the two application layers exchange messages between each other as though there were a bridge between them. o Communication at the application layer is between two processes.  a process sends a request to the other process and receives a response.

52. OSI Model Open Systems Interconnections (OSI) – approved by ISO Protocols or basics for creation of protocol for making any two systems to communicate w.o. changing the underlying the architecture Layered frameworkfor designing network systems Flexible, robust, interoperable network architecture

53. 1. Physical Layer It is the lowest layer of the OSI model. Main functionality to transmit the individual bits from one node to another node. It establishes, maintains and deactivates the physical connection. the mechanical, electrical and procedural network interface specifications. Functionality Line configuration – physical connection between devices Data transmission mode - …….. (simplex, half-duplex, full-duplex) Topology - Signals – analog or digital

54. Data-link layer It is for efficient and reliable communication Functionalities: Error-free data frames transfer Defines the format of data the unique identification of each device that resides on a local network

55. Sub-layers: Logical link control layer Responsible for transferring packets to n/w layer Identifies address of n/w layer protocol Provides flow control Media Access Control Layer Connects Links logical link and physical layer Transfers the packet

56. Functionality Framing – bits to frames, adds header and trailer – has both source and destination address Physical Addressing – destination address on the header Flow control – maintain a constant data rate on both side Error control – CRC added to the frame’s trailer – if error found then retransmission of packets Access control – priority of devices in the channel

57. Network Layer Manages device addressing Location tracking Choosing best path from source to destination – n/w condition, priority Device – router Network layer protocols – IPv4 and IPv6

58. Functions: Internetworking – logical connection between devices Addressing – hopping addresses Routing – finding best route Packetizing – frames to packets with IP

59. Transport layer Ensures messages are transmitted completely the same order they are sent No duplication of data Convert data received to segments Called as end-to-end layers – i.e. point-to-point connection Involves 2 protocols TCP Systems for communication – establishes connection between hosts – reliable protocol UDP Unreliable

60. Functions: Service-point addressing – adding service point address or port number to identify the process in the destination device Segmentation and reassembling – messages from upper layer is segmented and unique sequence number is given At the destination device the segments are ordered according to the sequence number

61. Connection control – Connection-oriented service – establishes a connection , all packets travel in the same route Connectionless service – no established connection - each packet travels into any possible route to reach the destination Flow control – in end-to-end and not point-to-point Error control – end-to-end – messages are send without any error

62. Session layer establish, maintain and synchronizes the interaction between communicating devices

63. Functions: Dialog control – creates dialog between processes in full or half-duplex modes Synchronization or recovery – adding checkpoints – retransmission of data if some errors in transmission

64. Presentation Layer Syntax and semantics of data Network translator in OS for converting data from one format to another format

65. Functions: Translation – end processes have different encoding methods Conversion from sender-dependent to common Common to receiver dependent Encryption – senders message encrypted – receiver decrypts Compression – reducing the number of bits to be transfered

66. Application layer as a window for users and application processes to access network service Handles – network transparency, resource allocation, etc.,

67. Functions: FTAM – allows access the files in a remote computer, to retrieve the files from a computer and to manage the files in a remote computer. Mail services – email forwarding and storing Directory services – distributed database sources

68. Physical Layer: Performance Bandwidth Bandwidth in Hertz – range of frequencies a channel can pass. In a telephone line – 4kHz Bandwidth in bps – the bits a channel can transfer . In ethernet 100 Mbps Mbps To Hz Formula The following formula is used to convert Mbps to Hz. F=(C)/Modulation V ariables: F is the frequency bandwidth (Hz) C is the data rate (Megabits per second) Modulation is the number of bits per Hz of bandwidth =14

69. Example: The bandwidth of a subscriber line is 4 kHz for voice or data. C=F*Modulation C=4kHz*14=4000Hz*14 = 56000 The bandwidth of this line for data transmission can be up to 56,000 bps using a sophisticated modem to change the digital signal to analog.

70. Example: If the telephone company improves the quality of the line and increases the bandwidth to 8 kHz, we can send 112,000 bps using a sophisticated modem to change the digital signal to analog.

71. throughput measure of how fast we can actually send data through a network Example – a link with a bandwidth of 1 Mbps, but the devices connected to the end of the link may handle only 200 kbps. This means that we cannot send more than 200 kbps through this link.

72. Example - A network with bandwidth of 10 Mbps can pass only an average of 12,000 frames per minute with each frame carrying an average of 10,000 bits. What is the throughput of this network? Solution: Data frames in the network = 12000 per min 1 frame = 10000 Therefore, Bits in the network per minute i.e., throughput in a min = 12000 x 10000 Throughput in a second =(12000 X 10000)/60 = 2000000 bps = 2 Mbps (1 Mbps = 1000000 bps)

73. Example - What is the propagation time if the distance between the two points is 12,000 km? Assume the propagation speed to be 2.4 × 10^8 m/s in cable. Solution - Propagation time = (12,000 x 1000) / (2.4 x 10^8) = 0.05 seconds = 50 ms (1 s = 1000 ms millisecond) Transmission time – of a message depends on the size of the message and the bandwidth of the channel. Transmission time = (Message size) / Bandwidth

74. Example - What are the propagation time and the transmission time for a 2.5-KB (kilobyte) message (an email) if the bandwidth of the network is 1 Gbps? Assume that the distance between the sender and the receiver is 12,000 km and that light travels at 2.4 × 10^8 m/s. Solution – Propagation time = (12,000 x 1000) / (2.4 x 108) = 0.05 s = 50 ms 2.5 KB = 2500 bytes = 2500 X 8 bits 1 Gbps = 10^9 bits Transmission time = (2500 x 8) / 10^9 =20000 /1000000000 = .00002 s = 0.020 ms

75. 1.7. Transmission Media Carry information from source to destination – physical layer and layer 0

76. Tx. Medium Free space, cable – metallic, fiber optics Information – in signal form Mediums – twisted pair, coaxial, optical fiber, air, vacuum Signals – electromagnetic energy – electric + magnetic – a portion of the spectrum

77. Guided Media twisted-pair cable, coaxial cable, and fiber-optic cable Physical mediums have their own limits twisted-pair cable, coaxial cable – signal in form of electric current Optical fiber – form of light

78. Twisted pair Two conductors with plastic insulation - twisted together One – carry signal to the receiver Other – ground reference Noise – twisted – let the noise do not affect Number of twists has effect on quality

79. Unshielded Twisted-Pair (UTP) vs Shielded Twisted-Pair (STP) Cable UTP STP UTP stands for Unshielded Twisted Pair. STP stands for Shielded Twisted Pair. UPP do not have any shields around it. STP cable has a metal foil or braided mesh covering that encases each pair of insulated conductors In UTP grounding cable is not necessary. While in STP grounding cable is required. Data rate in UTP is slow compared to STP. Data rate in STP is high. The cost of UTP is less. While STP is costlier than UTP. In UTP much more maintenance is not needed. While in STP much more maintenance is needed. In UTP noise is high compared to STP. While in STP noise is less.

80. Used in telephone lines and data channel Line connecting subscriber to central telephone office High data rate LAN

81. Coaxial cables Wire – insulator – metal braid – plastic cover Performance High bandwidth Signals get weaker rapidly Therefore need repeaters High attenuation than twisted pair Application High capacity telephone lines (10000 voice signals, Cable TV RG59 LAN ethernet

82. Fiber Optics A glass or fiber as a single medium Surrounded by cladding of glass or plastic

83. Performance Attenuation is much less Application Wider bandwidth Cable TVs

84. Unguided Media – wireless Communication No physical medium or conductors Uses free spaces Radio wave, Micro wave Infra Red

85. Radio Wave Electromagnetic spectrum – 3 kHz to 900 THz 3 kHz – 1 GHz – normal radio wave Omnidirectional Under 1 GHz – divided into sub bands Disadvantages As omni – waves from different antenna may create interference Cannot be isolated for inside and outside the building Advantages Used for broadcasting Received inside a building

86. Microwave Unidirectional EM waves 1GHz to 300GHz Narrow focusing – as unidirectional aligned without interference Obstacles prevents communication Making wider sub-bands Disadvantages Cannot penetrate wall Restricted – permission from authorities Application Unicast – Cellphones, satilite networks, wireless LANs

87. Infrared 300 GHz to 400 THz Advantages: Prevents inference Disadvantages Only for short rage communication Cannot be used under sun rays Application Remote controls

88. Switching Switch – connect two or more links Switching – transfer data packets / blocks via switches It prevents traffic Has information of devices connected to it  easy forwarding of packets Types Circuit-switched Packet-switched

89. Circuit-switched Network A dedicated connection called circuit between two devices Switch decides on active or inactive mode Is efficient when working in full capacity

90. Packet Switching Two ends connected via packets No continuous communication ROUTER – device Stores and forwards packets Capacity of communication is doubled Packets do not wait – point-to-point communication, else waits Efficient than circuit switch