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Overview of Data Communications and Networking

PART I. Overview of Data Communications and Networking. Overview. Chapters. Chapter 1 Introduction. Chapter 2 Network Models. Chapter 1. Introduction. 1.1 Data Communication.

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Overview of Data Communications and Networking

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  1. PART I Overview of Data Communications and Networking expanded by Jozef Goetz

  2. Overview expanded by Jozef Goetz

  3. Chapters Chapter 1 Introduction Chapter 2 Network Models expanded by Jozef Goetz

  4. Chapter 1 Introduction expanded by Jozef Goetz

  5. 1.1 Data Communication • Data communication is the transfer of data from one device to another via some form of transmission medium. • A data communications system must transmit data to the correct destination in an accurate and timely manner. • Components • Data Representation • Direction of Data Flow expanded by Jozef Goetz

  6. Figure 1.1Five components of data communication are the message, sender, receiver, medium, and protocol. expanded by Jozef Goetz

  7. Data Representation • text, • numbers, • images, • audio, and • video are different forms of information. expanded by Jozef Goetz

  8. expanded by Jozef Goetz

  9. expanded by Jozef Goetz

  10. Direction of Data Flow Figure 1.2Simplex e.g. the keyboard and the monitor expanded by Jozef Goetz

  11. Figure 1.3Half-duplex e.g. Walkie-talkies, CB radios expanded by Jozef Goetz

  12. Figure 1.4Full-duplex e.g. 2 people are communicating by a tel. line expanded by Jozef Goetz

  13. 1.2 Networks • A network is a set of communication devices connected by media links. expanded by Jozef Goetz

  14. 1.2 Networks • Distributed Processing • Task is divided • Network Criteria • Important: performance, reliability, security • Physical Structures • Categories of Networks expanded by Jozef Goetz

  15. 3. Physical Structures In a point-to-point connection, two and only two devices are connected by a dedicated link. Physical Structures Figure 1.5Point-to-point connection expanded by Jozef Goetz

  16. Figure 1.6Multipoint connection (timeshare connection – capacity) • In a multipoint connection, three or more devices share a link. expanded by Jozef Goetz

  17. 1.2 NETWORKS • How do we categorize? • Topology, geography • Technology • Geographic • Wide area networks • Metropolitan networks • Local area networks • Personal networks • Technologies • Circuit switched • Packet switched expanded by Jozef Goetz

  18. 4. Categories of Networks A topology is the geometric representation of the relationship of all the links and linking devices Figure 1.7Categories of topology (a network is layout physically) expanded by Jozef Goetz

  19. Figure 1.8Fully connected mesh topology (for five devices) Every device has a dedicated point to point link to every other device expanded by Jozef Goetz

  20. Figure 1.9Star topology • Each device has adedicated point to point link only to a central controller, called a hub • If one device wants to send data to another. • It sends the data to the controller, which then relays the data to the other connected device. expanded by Jozef Goetz

  21. Figure 1.10Bus topology is multipoint, previous all were point to point One long cable acts as a backbone connection connector expanded by Jozef Goetz

  22. Figure 1.11Ring topology Each device has a dedicated point to point link only with 2 devices on either side of it. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along. expanded by Jozef Goetz

  23. Figure 1.12Categories of networks • A network falls is determined by criteria: • Its size • Its ownership • The distance expanded by Jozef Goetz

  24. Figure 1.13LAN - Local Area Network • Designed for a single office, campus, building or between nearby buildings. • LANs allow resources to be shared • Hardware • Software • Data • between PCs or workstations. • License restriction expanded by Jozef Goetz

  25. Figure 1.13 LAN (Continued) A given LAN use only one type of transmission medium. Speed : 4-16 Mbps Today: 100 Mbps expanded by Jozef Goetz

  26. Figure 1.14 MAN Metropolitan Area Network (e.g. cable TV) Designed to extend over an entire city, connects LANs LANs can be shared - offices can be connected via a city expanded by Jozef Goetz

  27. Figure 1.15WAN - Wide Area Network Provides all transmission (data, video, image etc.) over large areas e.g. states, countries, a continent , or the whole world. In contrast to LANs may utilize public, leased, or private communication equipment. expanded by Jozef Goetz

  28. EO - End Office PSTN – Public Switching Telephony Network PBX – Private Exchange Switch expanded by Jozef Goetz

  29. 1.3 The Internet • A Brief History • The Internet Today • When 2 or more networks are connected, they become an internetwork, or internet. • An internet is a network of networks. • The Internet(upper case) is a collaboration of more • than 100s thousands interconnected networks. • The Internet is a structured, organizedcollection of many separate networks. • TCP/IP is the protocol suite for the Internet. expanded by Jozef Goetz

  30. Figure 1.16Internet today There are local, regional, national, and international Internet service providers (ISPs). NAP = Network Access Point is the complex switching stations. Speed: up to 600 Mbps • End users to be connected use the services • of Internet Service Provider (ISP) expanded by Jozef Goetz

  31. Figure 1.16Internet today NAP = Network Access Point Up to 600 Mbps expanded by Jozef Goetz

  32. 1.4 Protocols and Standards • Protocols • Set of rules that governs data communication • Key elements: • Syntax • Structure or format – order in which they are presented • Semantics • Meaning of each section of bits • Timing • What data and how fast they can be sent expanded by Jozef Goetz

  33. 1.4 Standards • A standard provides a model for development that enables a product to work regardless of the individualmanufacturer • Standards are essential in: • i. Creating competitive markets for equipment manufacturers • ii. Guaranteeing national and international interoperability and compatibility expanded by Jozef Goetz

  34. 1.4 Standards Categories • De Facto (by fact) standards • Proprietary • Nonproprietary • De Jure (by law) standards expanded by Jozef Goetz

  35. 1.4 Protocols and Standards • Standards Organizations • The ISO, • ITU-T (previously CCITT), • ANSI, • IEEE, and • EIA are some of the organizations involved in standardscreation. expanded by Jozef Goetz

  36. 1.4 Protocols and Standards Forum • Consist of representatives from interested corporations • Present their conclusions to the standards bodies • Facilitate standardization process • Frame Relay Forum • ATM Forum and Consortium • Internet Society (ISOC) and Internet Engineering Task Force (IETF) expanded by Jozef Goetz

  37. 1.4 Protocols and Standards Forum • are special-interest groups (work with universities and users), that evaluate and standardize new technologies. • Internet Standards • A Request for Comment (RFC) is an idea or concept that is a precursor to an Internet standard. expanded by Jozef Goetz

  38. 1.4 Protocols and Standards • ISO (International Standards Organization) 1946 – vast number of subjects • 89 countries • 13000 standards • ISO is a member of ITU-T • Documents are: • Draft • Draft International • International Standard • ANSI (American National Standards Institute) • Private, nongovernmental, nonprofit organization • NIST (National Institute of Standards and Technology) – a part of the US Dept of Commerce • IEEE (Institute of Electrical and Electronics Engineering) • Largest professional organization in the world • ITU-T International Telecommunications Union - Telecommunications Standardization Sector (former CCITT) – 3000 recommendations expanded by Jozef Goetz

  39. 1.4 Protocols and Standards • ISO • ISO 8877—Interface in Integrated Services Digital Network (ISDN) • ISO 3309—HDLC frame structure • ISO 8028—X.25 packet level protocol expanded by Jozef Goetz

  40. 1.4 Protocols and Standards • ITU-T • V.32: Defines data transmission over phone lines • X.25: Defines transmission over public digital networks • I.430: Define physical layer specifications for an interface expanded by Jozef Goetz

  41. 1.4 Protocols and Standards • ANSI • X3. 23-1985 Programming language COBOL • SONET Synchronous Optical Network • ISDN Integrated Services Digital Network expanded by Jozef Goetz

  42. 1.4 Protocols and Standards • IEEE • IEEE 802.3: CSMA/CD LAN • IEEE 802.4: TokenBus LAN • IEEE 802.5: TokenRing LAN expanded by Jozef Goetz

  43. 1.4 Protocols and Standards • EIA • EIA-232: A 25-pin interface standard • EIA-449: Specifies a 37-pin connector and a 9-pin connector • EIA-530: Defines a 25-pin connector expanded by Jozef Goetz

  44. 1.4 Regulatory Agencies Federal Communication Commission (FCC) • Authority for interstate and international traffic • Reviews communication services and prices • Reviews technical specs of communication hardware • Assigns carrier frequencies for radio and television Public Utility Commission • Authority for intrastate traffic expanded by Jozef Goetz

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