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Business Data Communications, Fourth Edition

Business Data Communications, Fourth Edition. Chapter 6: Protocols. Learning Objectives. Describe the role of software in a data communications network Define a protocol and how it is used in a network Explain the Open Systems Interconnection (OSI) model List the types of protocols

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Business Data Communications, Fourth Edition

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  1. Business Data Communications, Fourth Edition Chapter 6: Protocols

  2. Learning Objectives • Describe the role of software in a data communications network • Define a protocol and how it is used in a network • Explain the Open Systems Interconnection (OSI) model • List the types of protocols • Differentiate between wide area and local area network protocols Chapter 6: Protocols 2

  3. Learning Objectives • List and explain Internet protocols • Describe the difference among character-oriented, byte-count-oriented, and bit-oriented protocols, H.323, and X.25 protocols • Describe the protocols and standards used in wireless networks • Describe the protocols used for Apple Macintosh networks Chapter 6: Protocols 3

  4. Introduction • Early networks consisted of equipment from one manufacturer • Modern networks are made up of different equipment from different manufacturers • Rules are needed to allow the equipment to communicate over a network Chapter 6: Protocols 4

  5. The Role of Software in a Network • Software is made up of programs that control data transmission • All devices run some type of software • Computers (servers), controllers, clients (including terminals) all use software in a WAN • Servers and clients use software in a LAN Chapter 6: Protocols 5

  6. Protocols • Set of rules that defines how devices communicate • Translates codes within the devices • Three key elements of protocols • Syntax – format of data, transmission coding schemes • Semantics – control information • Timing – controlling flow of data on network, match device speeds on the network, provides sequencing for data • Early protocols were proprietary Chapter 6: Protocols 6

  7. Protocols • Open Systems Interconnection (OSI) Model • A standard for communications systems • Composed of seven layers • Application layer – allows user access to the network • Presentation layer – defines format of the data • Session layer – establishes and maintains network connection • Transport layer – maintains connections between networks Chapter 6: Protocols 7

  8. Chapter 6: Protocols 8

  9. Chapter 6: Protocols 9

  10. Protocols • Open Systems Interconnection Model • 7 Layers (cont.) • Network layer – creates packets, adds address and routing information • Route is the path data takes • Adaptive versus dynamic routing • Routing tables • Data link layer – establishes and controls physical path, creates frames • Physical layer – concerned with hardware, makes the physical connection Chapter 6: Protocols 10

  11. Chapter 6: Protocols 11

  12. Chapter 6: Protocols 12

  13. Types of Protocols • Introduction • Different types for mainframe computers, personal computers, wireless networks • No standard set of protocol for all devices • Communications developed in an atmosphere of competition • Data link protocols – rules for implementing the data link layer Chapter 6: Protocols 13

  14. Wide Area Network Protocols • Mainframe Computer Protocols • Character-Oriented Protocols • Binary Synchronous Communications (BSC) • Data sent as blocks of characters (synchronous) • Used only for half-duplex transmission • Uses special characters for control • Byte-Count-Oriented Protocols • Adds the number of characters instead of special control characters • Digital Data Communication Message Protocol (DDCMP) Chapter 6: Protocols 14

  15. Figure 6-6. BSC data with control characters. Figure 6-7. Format for byte-count-oriented protocol. Chapter 6: Protocols 15

  16. Wide Area Network Protocols • Mainframe Computer Protocols • Bit-Oriented Protocols • Data and control information put in frames • Different protocols created by many companies • SDLC – IBM • HDLC – ISO Standard Figure 6-8. HDLC, SDLC frame format. Chapter 6: Protocols 16

  17. Wide Area Network Protocols • Mainframe Computer Protocols • Systems Network Architecture (SNA) • Originally used on IBM mainframe networks • Now used in other networks as well • Uses a layered model • Old model – 5 layers • Modern model – 7 layers • More compatible with OSI model Chapter 6: Protocols 17

  18. Figure 6-9. Comparison among old SNA, new SNA, and OSI layered Model. Chapter 6: Protocols 18

  19. Wide Area Network Protocols • Mainframe Computer Protocols • H.323 Protocol • Real-time audio, video, and data communications on packet-switched networks • Multimedia presentation over a network Chapter 6: Protocols 19

  20. Chapter 6: Protocols 20

  21. Wide Area Network Protocols • Mainframe Computer Protocols • X.25 Protocol • Packet switching protocol • Uses only the bottom 3 layers of the OSI model Chapter 6: Protocols 21

  22. Internet Protocols • Transmission Control Protocol/Internet Protocol (TCP/IP) • Developed in 1973 for ARPANET • The first Wide Area Network protocol • Five layer model • Data broken up in to packets • TCP segment • IP datagram Chapter 6: Protocols 22

  23. Chapter 6: Protocols 23

  24. Chapter 6: Protocols 24

  25. Internet Protocols • Internet Protocol Version 6 (IPv6) • AKA Internet Protocol next generation (IPng) • Address length increased to 128 bits • Allows the addition of more Internet Web sites • Allows for growth for the Internet Chapter 6: Protocols 25

  26. Internet Protocols • Other Internet Protocols • File transfer protocol (ftp) • Hypertext transfer protocol (http) • Electronic Mail Protocols • X.400 (e-mail standard) • X.500 (public e-mail directory standard) • Post Office Protocol 3 (POP3) – e-mail downloaded to user’s computer • Internet Message Access Protocol (IMAP) – e-mail stored on server, even after it is read • Simple Mail Transfer Protocol (SMTP) – used for sending only Chapter 6: Protocols 26

  27. Local Area Network Protocols • Local Area Network • Limited area • X.PC • Converts asynchronous data for transmission on a packet switching network • Ethernet • Contention access method • Carrier Sense Multiple Access with Collision Detection (CSMA/CD) • Fast Ethernet (100 Mbps) • Gigabit Ethernet (1 Gbps) • 10-Gigabit Ethernet (10 Gbps) Chapter 6: Protocols 27

  28. Local Area Network Protocols • Token Passing • Token • Token ring • 4Mbps or 16Mbps • Uses Multistation Access Unit (MAU) • Fast token ring (high-speed ring) (100 Mbps) • Fiber Distributed Data Interface (FDDI) Chapter 6: Protocols 28

  29. Chapter 6: Protocols 29

  30. Chapter 6: Protocols 30

  31. Local Area Network Protocols • Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) • Used on Novell LANs • Incorporates features of discontinued Xerox Network System (XNS) • Uses lower 3 layers of OSI model • Data link layer divided • Logical Link Control (LLC) • Media Access Control (MAC) Chapter 6: Protocols 31

  32. Chapter 6: Protocols 32

  33. Wireless Protocols and Standards • Cellular Digital Packet Data (CDPD) • AKA Wireless IP protocol • Used on wireless packet switched networks • Uses radio frequencies, up to 19.2 Kbps • Allows multicast messages • Connects to the wired network as well Chapter 6: Protocols 33

  34. Chapter 6: Protocols 34

  35. Wireless Protocols • Wireless Application Protocol (WAP) • Allows wireless devices to have Internet access • Browser exists on hand-held device • Server software is at the wireless service provider • Devices that adhere to the protocol are called “WAP-enabled” Chapter 6: Protocols 35

  36. Wireless Protocols • Infrared Data Association (IrDA) • Provides point-to-point link • PDAs, keyboards, mouse • Limitations on length of signal • Line of sight transmission Chapter 6: Protocols 36

  37. Wireless Protocols • Third Generation (3G) of Mobile Communications • Technology for future wireless applications • Proposes standards • Voice and data communications technologies of the future • Propose to put W-CDMA on an IP network Chapter 6: Protocols 37

  38. Wireless Protocols • Bluetooth • Short-range radio links • Printers, mouse, keyboard connected to PC without wires • Bluetooth networks • Piconet – point-to-point between two devices • Scatternet – Two or more piconets communicating Chapter 6: Protocols 38

  39. Chapter 6: Protocols 39

  40. Chapter 6: Protocols 40

  41. Wireless Protocols • Enhanced Data Rates for Global Evolution (EDGE) • Standard for GSM and TDMA networks • Transmission up to 384 Kbps • Part of the evolution to 3G Chapter 6: Protocols 41

  42. Wireless Protocols • SyncML • Common language for synchronizing data on mobile devices • XML protocol • Mobile devices need to communicate with networks so synchronization is needed • Over 300 companies involved in developing SyncML Chapter 6: Protocols 42

  43. AppleTalk Protocol • Used with Macintosh computers • Uses CSMA/CA • Uses a 7-layer model • Interfaces with other LANs Chapter 6: Protocols 43

  44. Chapter 6: Protocols 44

  45. Summary • Networks made up of hardware and software • Software exists on every network device • Protocols are rules for communications • OSI is a model for protocol standards • Mainframe computer protocols differ from personal computer protocols Chapter 6: Protocols 45

  46. Summary • Multimedia networks use the H.323 protocol • X.25 used on packet switching networks • Internet protocols include TCP/IP, IPv6, and several e-mail protocols • Local area network protocols include X.PC, Ethernet, and token ring • Wireless networks include CDPD and WAP • Macintosh networks use AppleTalk Chapter 6: Protocols 46

  47. Chapter 6 Complete

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