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Introduction

This article discusses data communication, covering local and remote exchange, protocols, standards, networks, and security, emphasizing the importance of reliable and secure communication. It explains the components of data communication, network criteria, and key protocols and standards such as syntax, semantics, and timing. The text explores the impact of performance, reliability, and security on data communication networks and the significance of adhering to industry standards for efficient communication. It also delves into the roles of various applications in utilizing data communication effectively. Overall, it aims to provide a comprehensive understanding of data communication principles and practices.

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Introduction

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Presentation Transcript

  1. Introduction

  2. Data Communication • Communication • Sharing information : Local & Remote • Local • Face to face, between individuals • Remote • Over distance • Requires “telecommunication” media/method • Telephony • Telegraphy • Television • Telecommunication = communication at distance (tele = far (Greek))

  3. Data Communication • Data refers to • Facts • Concepts • Instructions • Presented in any form agreed upon by the parties creating and using the data • In computer information system • Data are represented by 0/1

  4. Data Communication In summary • Data communication = the exchange of data (0s/1s) between two devices via some form of transmission media (i.e. cable) • Local communication • Devices are in the same building • Remote communication • Devices are far apart

  5. Data Communication • Data communication process  to occur • hardware  communication devices • Software  communication software

  6. Data Communication • Three fundamental characteristics (provide data communication system effectiveness) • Delivery (to the right party) • Accuracy (0  0 / 1  1 NOT 0  1 ) • Timeliness

  7. Components Step1 : Step2: Step3: …… t Step1 : Step2: Step3: …… Protocol Protocol message medium sender receiver

  8. Components • Messages • Data to be communicated • Any form (text, pictures, sound, video, etc.) • Sender/Receiver • Device that sends/receives the data message • It can be : computer, telephone, etc. • Medium • Twisted pair wire, coaxial cable, etc. • Protocol : Rules.

  9. Networks • A set of devices (node) connected by media links • A node can be • Computer • Printer • Any other devices capable of sending and receiving data • The link is often called “communication channel” • Uses “Distributed Processing”

  10. Networks • Network Criteria Data communication network criteria Performance Reliability Security

  11. Networks • Network Criteria Data communication network criteria Performance Reliability Security

  12. Network Criteria • Performance measures • Transit time • Traveling time from one device to another • Response time • Time between an inquiry and a response

  13. Network Criteria : Performance • Important Factors (for performance) • Number of users • Type of transmission medium • Hardware • Software

  14. Networks • Network Criteria Data communication network criteria Performance Reliability Security

  15. Network Criteria • Reliability : measured by • Frequency of failures • Recovery time of a network after failure • Protected from unforeseen damage • Fire • Flood • etc.

  16. Networks • Network Criteria Data communication network criteria Performance Reliability Security

  17. Network Criteria • Security : Protecting data from unauthorised access and viruses • Unauthorised access • Password • Encryption • Viruses • A good network must be protected from viruses by hardware and software

  18. Applications • Marketing and sales • Financial services • Manufacturing • Electronic messaging • Directory services • Information services • Electronic data interchange (EDI) • Teleconferencing • Cellular telephone • Cable television

  19. Protocols and Standards • Protocols • A set of rules that govern data communication • Defines • What is communicated • How it is communicated • When it is communicated • Key elements of a protocol • Syntax • Semantics • timing

  20. Protocols and Standards • Syntax • Format of data : i.e. the first 8 bits = sender address the second 8 bits = receiver address the rest = data or message • Semantic • Meaning of each section of bits • How is a pattern to be interpreted • What action is to be taken • i.e.  does the address identify the route to be taken or the final destination of the message

  21. Protocols and Standards • Timing • When data should be sent • How fast they can be sent • For example : • Sender produces 100 Mbps  sender can receive 1 Mbps • Overload the receiver • Data lost

  22. Standards • Facts: • Devices from different manufacturers • Different signal/methods/data • Standards are necessary • Data communication standards • de facto (by fact or by convention) • de jure (by law or by regulation)

  23. Standards organisations • Standards creation committee • ISO • CCITT • ANSI • IEEE • EIA • Forums • Frame Relay Forum • ATM Forum and ATM Consortium • ISOC and IETF

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