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Data Communication & Computer Networks
This document provides an overview of a course on data communication and computer networks. It includes 5 units that cover topics such as introduction to data communication components, network models, physical layer, data link layer, network layer, congestion control, and the transport layer. It also lists 10 experiments related to the course content, such as implementing network commands, cyclic redundancy code, routing algorithms, and domain name servers. The instructor's name and some content that is copied from internet sources is acknowledged.
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Data Communication & Computer Networks
- 1. Data Communication and Computer Networks ComputerNetworks *Note: Some content is copied from internet source. I thank the creators of the copied content. Data Communication and Computer Networks Computer Networks Course Instructor: Dr. C. Sreedhar *Note: Some content is copied from internet source. I thank the creators of the copied content.
- 3. Unit 1 Introduction: DataCommunication, Components, Data Representations, Dataflow, Network Topologies, categories of networks, Internet, protocols and standards. Internet, protocols and standards. Network Models: Layered tasks, OSI Reference model, layers in OSI model, TCP/IP Protocol suit, Addressing – Physical address, Logical address, port addresses. Unit 1 Data Communication, Components, Data Representations, Dataflow, Network Topologies, categories of networks, Internet, protocols and standards. Internet, protocols and standards. Layered tasks, OSI Reference model, layers in OSI model, Physical address, Logical address, port addresses.
- 4. Unit 2 Physical layerand Transmission Media: Analog and digital signals, Digital signals –Bit rate, Bit length, Transmission of digital signals, Transmission Impairments – Attenuation, Distortion and Noise, Transmission Impairments – Attenuation, Distortion and Noise, Performance – Bandwidth, Throughput, Latency, Jitter. Data Link Layer: Error detection – Introduction, Block coding detection, error correction, hamming distance and minimum hamming distance, CRC codes, Checksum. Unit 2 Physical layer and Transmission Media: and digital signals, Bit rate, Bit length, Transmission of digital signals, Attenuation, Distortion and Noise, Attenuation, Distortion and Noise, Bandwidth, Throughput, Latency, Jitter. Introduction, Block coding – error detection, error correction, hamming distance and minimum hamming distance, CRC
- 5. Unit 3 Network layer: DesignIssues - store-and- Services to transport layer Connection oriented services Routing Algorithms: Routing Algorithms: The optimality principle, shortest path routing, Flooding, Distance vector and Link state, Multicast Routings. Unit 3 -forward, Services to transport layer - Connection less and Connection oriented services The optimality principle, shortest path routing, Distance vector and Link state,
- 6. Unit 4 Congestion Control: Principles,congestion prevention policies, congestion control in virtual circuits and datagram subnets, load shedding, jitter control. Internetworking: Internetworking: Tunneling, Internet work routing, Fragmentation. The IP protocol, IP address, Gateway routing protocols: OSPF, BGP. Unit 4 Principles, congestion prevention policies, congestion control in virtual circuits and datagram subnets, load shedding, jitter control. Tunneling, Internet work routing, Fragmentation. The IP protocol, IP address, Gateway routing protocols: OSPF, BGP.
- 7. Unit 5 Transport Layer: UDP,TCP- service model, protocol, segment header, connection management, Transmission Policy. Application Layer: The DNS Name Space, The DNS Name Space, Resource Records, Name Servers. Unit 5 service model, protocol, segment header, connection management, Transmission Policy. Resource Records, Name Servers.
- 9. DCCN Lab: Listof Experiments Basic network command and Network configuration commands. Create a network models using packet tracer. Perform an Initial Switch Configuration using packet tracer Investigate the TCP-IP and OSI Models using packet tracer Implement Cyclic Redundancy Code Implement Dijkstra’s algorithm to find the best path Implement the Distance vector routing algorithm. Implement congestion control using leaky bucket algorithm Implement Domain name server Implement client server model DCCN Lab: List of Experiments Basic network command and Network configuration commands. Create a network models using packet tracer. Perform an Initial Switch Configuration using packet tracer IP and OSI Models using packet tracer Implement Cyclic Redundancy Code algorithm to find the best path Implement the Distance vector routing algorithm. Implement congestion control using leaky bucket algorithm
- 10. Unit 1 • DataCommunications • Definition • Components of DC • Data representation • Data flow • Data flow • Networks • Network criteria • Types of connections • Categories of topology • Network Models Unit 1 • Protocols and Standards • Definition • Standards
- 11. ata Communication: Definition Datacommunications are the exchange of data between two devices via some form of transmission devices via some form of transmission medium such as a wire cable. ata Communication: Definition
- 12. Data Communication The effectivenessof a data communications system depends on four fundamental characteristics: • Delivery: deliver data to the correct destination • Accuracy: system must deliver the data accurately • Accuracy: system must deliver the data accurately • Timeliness: system must deliver data in a timely manner • Jitter: refers to the variation in the packet arrival tim The effectiveness of a data communications system depends on four fundamental characteristics: : deliver data to the correct destination : system must deliver the data accurately : system must deliver the data accurately : system must deliver data in a timely : refers to the variation in the packet arrival tim
- 13. ata Communication: Components vecomponents Sender Message Transmission medium Transmission medium Protocol Receiver otocol is defined as a set of s that governs data munications. ata Communication: Components
- 14. ements of aProtocol • Syntax • Structure or format of the data • Indicates how to read the bits - • Semantics • Interprets the meaning of the bits Elements of Protocol 1.14 • Interprets the meaning of the bits • Knows which fields define what action • Timing • When data should be sent and what • Speed at which data should be sent or speed at which it is being received. Structure or format of the data field delineation Interprets the meaning of the bits Elements of Protocol Interprets the meaning of the bits Knows which fields define what action When data should be sent and what Speed at which data should be sent or speed at which it is being
- 15. Data Representation • Text: •Text is represented as a bit pattern. • Unicode uses 32 bits to represent a symbol or character • Numbers • Numbers are also represented by bit patterns. • number is directly converted to a binary number • number is directly converted to a binary number • Images • Images are also represented by bit patterns. • image is composed of a matrix of pixels • each pixel is assigned a bit pattern. • Audio and Video: Text is represented as a bit pattern. Unicode uses 32 bits to represent a symbol or character Numbers are also represented by bit patterns. number is directly converted to a binary number number is directly converted to a binary number Images are also represented by bit patterns. image is composed of a matrix of pixels
- 16. Data Flow mmunication betweentwo devices can be simplex or half l-duplex mmunication between two devices can be simplex or half-duplex, or
- 17. Review •Data Communications • Definition •Characteristics that affect DC • Components of DC • Data representation • Data representation • Data flow Characteristics that affect DC
- 18.
- 19. NETWORKS NETWORKS network network is is a aset set of of devices devices (nodes (nodes nks nks. . node node can can be be a a computer, computer, printer, printer, ending ending and/or and/or receiving receiving data data generated generated ending ending and/or and/or receiving receiving data data generated generated etwork etwork. . link link can can be be a a cable, cable, air, air, optical optical ansport ansport a a signal signal carrying carrying information information NETWORKS NETWORKS (nodes (nodes) ) connected connected by by communicatio communicatio printer, printer, or or any any other other device device capable capable generated generated by by other other nodes nodes on on th th generated generated by by other other nodes nodes on on th th optical optical fiber, fiber, or or any any medium medium which which ca ca information information. .
- 20. Network Criteria • Performance: •Measured: transit time and response time • Transit time: time required for a message to travel from A • Response time: elapsed time between inquiry and response • Evaluated using two metrics: • Evaluated using two metrics: • throughput and delay (more throughput and less delay). • Reliability: • measured by the frequency of failure • Security • Network security issues include protecting data from unauthorized access Measured: transit time and response time Transit time: time required for a message to travel from AB Response time: elapsed time between inquiry and response throughput and delay (more throughput and less delay). measured by the frequency of failure Network security issues include protecting data from unauthorized access
- 21. • Point toPoint - single transmitter and Ex: Television remote control • Multipoint - multiple recipients of single transmission • Ex: Telephone Line Types of Connections single transmitter and receiver multiple recipients of single transmission Types of Connections
- 22. Physical topology ology refersto the way in which a network is laid out physically Physical topology ology refers to the way in which a network is laid out physically
- 23. Mesh topology every devicehas a dedicated point every other device. Total no. of connections??? Manages high amounts of traffic Manages high amounts of traffic Withstands failure of link. Adding nodes easily added Can avoid problems, malicious users amount of cabling number of I/O ports installation and reconnection are difficult ctical example: connection of ephone regional offices topology every device has a dedicated point-to-point link every other device. Total no. of connections??? n(n-1)/2 Advantages Manages high amounts of traffic Manages high amounts of traffic Withstands failure of link. Adding nodes easily added Can avoid problems, malicious users Disadvantages amount of cabling number of I/O ports installation and reconnection are difficult
- 24. A star topology Ifthe hub goes down, the whole system goes down. e star topology is used in local-area tworks (LANs) each device needs only one link and on I/O port to connect it to any number of others Advantages less expensive than a mesh topology. robust: If one link fails, only that link is robust: If one link fails, only that link is affected Disadvantages If the hub goes down, the whole system goes down.
- 25. bus topology des areconnected to the bus cable by drop lines and taps rop line is a connection running between device and main cable. ap is a connector ap is a connector e long cable acts as a backbone to link all the devices in a network Advantages s uses less cabling than mesh or star topologies Disadvantages ficult reconnection and fault isolation gnal reflection at the taps can cause degradation ault or break in the bus cable stops all transmission topology des are connected to the bus cable by drop lines and taps rop line is a connection running between device and main cable. e long cable acts as a backbone to link all the devices in a network Advantages s uses less cabling than mesh or star topologies Disadvantages gnal reflection at the taps can cause degradation ault or break in the bus cable stops all transmission
- 26.
- 27. Ring Topology Each devicehas a dedicated point to point connection with only two devices on e e of it. Signal is passed along the ring in one direction till it reaches destination Each device has a repeater When a device receives signal to be passed, its repeater regenerates bits and sses along. Advantages asy to install and reconfigure ault isolation is simple Disadvantages directional traffic ak in the ring disables entire network; solved by dual ring Ring Topology Each device has a dedicated point to point connection with only two devices on e Signal is passed along the ring in one direction till it reaches destination When a device receives signal to be passed, its repeater regenerates bits and Advantages Disadvantages ak in the ring disables entire network; solved by dual ring
- 28. A hybrid topology:a star backbone with three bus networks Main Star topology with each branch connecting several stations in a bus topology hybrid topology: a star backbone with three bus networks Main Star topology with each branch connecting several stations in a
- 29. • Local AreaNetworks (LANs) • Short distances • Designed to provide local interconnectivity • Wide Area Networks (WANs) • Long distances • Provide connectivity over large areas Categories • Provide connectivity over large areas • Metropolitan Area Networks (MANs) • Provide connectivity over areas such as a city, a campus Categories of Networks Provide connectivity over areas such as a city, a campus
- 30. AN N vately owned andlinks devices in a single office,building,campus N size is limited to few kms Ns allow resources to be shared between devices. N uses oonly one type of transmission medium mmon LAN topologies: Bus, Star, Ring ta rate in LANs 100 or 1000 Mbps office,building,campus. Ns allow resources to be shared between devices. one type of transmission medium
- 31. WANs: a switchedWAN and a point : a switched WAN and a point-to-point WAN
- 32. A heterogeneous networkmade of four WANs and two LANs heterogeneous network made of four WANs and two LANs
- 33. LAN MAN ocal AreaNetwork Metropolitan Area Network onnects group of computers in small geographic area Covers large region such as cities, towns etup cost is low Setup cost is higher than LAN andwidth is low Bandwidth is higher than LAN wisted pair, fiber optic cables Twisted pair, fiber optic cables overage: ~ 2 miles Coverage: 100 miles MAN WAN Metropolitan Area Network Wide Area Network Covers large region such as Spans large locality and connects countries together Setup cost is higher than LAN Most expensive network setup Bandwidth is higher than LAN Highest bandwidth among all types of networks Twisted pair, fiber optic cables High speed communications: fiber optic, wireless, satellite Coverage: 100 miles Coverage: 1000 Km
- 34. Elements of Protocol Elementsof a protocol: • Syntax • Semantics • Timing yntax: structure or format of data yntax: structure or format of data
- 35. Elements of protocol •Semantics: meaning of each section of bits Timing: when data should be sent and how fast they can be sent meaning of each section of bits when data should be sent and how fast they can be sent
- 36. Standards o categories De facto:not approved by an organized body but adopted De jure: Legislated by an officially recognized body ndards Creation Committees International Standards Organization (ISO) International Standards Organization (ISO) International Telecommunications Union (ITU) American National Standards Institute (ANSI) Institute of Electrical and Electronics Engineers (IEEE) Electronic Industries Association (EIA) Internet Engineering Task Force (IETF : not approved by an organized body but adopted : Legislated by an officially recognized body International Standards Organization (ISO) International Standards Organization (ISO) International Telecommunications Union (ITU) American National Standards Institute (ANSI) Institute of Electrical and Electronics Engineers (IEEE) Electronic Industries Association (EIA) Internet Engineering Task Force (IETF)
- 38. Need for LayeredArchitecture • E.g., A can only speak Chinese, B can only speak Spanish, how can A communicate with B? • A finds a translator C, who can speak Chinese and English • B finds a translator D, who can speak Spanish and English • Two layers: • Two layers: • Higher layer: A and B • Lower layer: C and D Need for Layered Architecture E.g., A can only speak Chinese, B can only speak Spanish, how can a translator C, who can speak Chinese and English a translator D, who can speak Spanish and English 38
- 39. A Two-layer example messagesin How to communicate? A r messages in Chinese messages in English C Lower layer provides services to the next higher layer. messages in How to communicate? B 39 messages in English messages in Spanish D Lower layer provides services to the next higher layer.
- 40.
- 41. Origin for ISOOSI Model Origin for ISO OSI Model
- 42. HE HE OSI MODEL OSIMODEL ablished ablished in in 1947 1947, , the the International International multinational multinational body body dedicated dedicated to to worldwide worldwide ndards ndards. . ISO ISO standard standard that that covers covers all all aspects aspects ISO ISO standard standard that that covers covers all all aspects aspects Open Open Systems Systems Interconnection Interconnection (OSI) (OSI) he he late late 1970 1970s s. . International International Standards Standards Organization Organization (ISO) (ISO) is is worldwide worldwide agreement agreement on on international international aspects aspects of of network network communications communications is is aspects aspects of of network network communications communications is is (OSI) (OSI) model model. . It It was was first first introduced introduced
- 43. Seven layers ofthe OSI model layers of the OSI model
- 44. The interaction betweenlayers in the OSI model interaction between layers in the OSI model
- 45. exchange using theOSI model using the OSI model
- 46. Layer 1: PhysicalLayer Responsible of: • Transmitting individual bits from one to the next. • Physical characteristics of interface and media. • Representation of bits: a stream of bit(0s,1s), • Data rate. • Data rate. • Synchronize of bits • Line configuration • Physical topology • Transmission mode Layer 1: Physical Layer Transmitting individual bits from one to the next. Physical characteristics of interface and media. Representation of bits: a stream of bit(0s,1s),
- 47.
- 48. Layer 2: DataLink layer Responsible of: • Moving frames from one hop (node) to the next. • Framing: divided the stream of bits received from the network layer manageable data units called frames. • Physical address (MAC address). • Physical address (MAC address). • Flow control. • Error control: added trailer to the end of frame. • Access control. • Hop to hop delivery Layer 2: Data Link layer Moving frames from one hop (node) to the next. Framing: divided the stream of bits received from the network layer Error control: added trailer to the end of frame.
- 49. Data Link layercont. 10110110101 01100010011 01100010011 10110000001
- 50.
- 51. Data Link LayerExample Data Link Layer Example