1 / 60

Business Data Communications, Fourth Edition

Business Data Communications, Fourth Edition. Chapter 7: Network Concepts. Learning Objectives. Define the terms used when describing a network and its components List the differences among circuit-switching, message-switching, packet-switching, and cell-switching networks

andrew
Download Presentation

Business Data Communications, Fourth Edition

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Business Data Communications, Fourth Edition Chapter7: NetworkConcepts

  2. Learning Objectives • Define the terms used when describing a network and its components • List the differences among circuit-switching, message-switching, packet-switching, and cell-switching networks • List the types of routing techniques used to move data through a network Chapter 7: Network Concepts 2

  3. Learning Objectives • Describe the difference between a public network and private network • Illustrate the difference between a LAN and a WAN • Describe the functions of the Internet and intranets Chapter 7: Network Concepts 3

  4. Learning Objectives • Describe the characteristics that distinguish a distributed network from other types of networks • List the types of distributed processing • Describe the types of files used in distributed systems Chapter 7: Network Concepts 4

  5. Introduction • Basic concepts and terminology are needed for a foundation of the study of networks • Network switching and routing is critical to network operation • Network ownership • Types of networks • LANs • WANs • Internet • Intranets • Distributed Networks Chapter 7: Network Concepts 5

  6. Basic Network Concepts • Network – the interconnection of devices for communications • Servers (hosts) – independent computer systems • Node – device with a network address • Link – connection between adjacent nodes • Path – series of links • Circuit – End-to-end connection (made up of links and paths) Chapter 7: Network Concepts 6

  7. Chapter 7: Network Concepts 7

  8. Chapter 7: Network Concepts 8

  9. Chapter 7: Network Concepts 9

  10. Networking Techniques • Non-switched network – Point-to-point link • Switched Networks – Nodes interconnected • Circuit-Switching • Dedicated path • Entire circuit must be available • Telephone network • Inefficient for data transmission • Used for intermittent data transmission Chapter 7: Network Concepts 10

  11. Chapter 7: Network Concepts 11

  12. Networking Techniques • Switched Networks • Message-switching • No dedicated circuit required • Messages pass through many nodes to the destination • Store-and-forward technique used • Similar to post office mail delivery • Some delays in delivery may occur Chapter 7: Network Concepts 12

  13. Chapter 7: Network Concepts 13

  14. Networking Techniques • Switched networks • Packet-switching • Similar to message-switching, but uses a fixed-size message, called a “packet” • All packets are the same length • Network performance is much better than on a message-switching network • Pipelining used • Instructions are available as soon as necessary to the receiving computer • Provides faster execution time Chapter 7: Network Concepts 14

  15. Chapter 7: Network Concepts 15

  16. Chapter 7: Network Concepts 16

  17. Networking Techniques • Switched Networks • Packet-switching – Types • Datagram services – each packet treated independently • Switched Virtual Circuit (SVC) – logical connection established prior to transmission • Permanent Virtual Circuit (PVC) – permanent circuit, no call setup is needed Chapter 7: Network Concepts 17

  18. Networking Techniques • Switched Networks • Cell-switching • Used in Asynchronous Transfer Mode (ATM) networks • Cell-based network • Cell is 53 bytes long • Uses a virtual circuit • More in Chapter 13 Chapter 7: Network Concepts 18

  19. Networking Techniques • Broadcast Networks • Use radio waves • Packet radio network • National Weather Service uses it to gather information from remote sites • Also used on the U.S. Space Shuttle and the International Space Station (ISS) • Special modem is used • Uses the AX.25 protocol and TCP/IP Chapter 7: Network Concepts 19

  20. Routing • Computers use routing to send data to the correct destination • Centralized routing • One node is the network routing manager • Central point of failure • Routing information may be far from central node • Distributed routing • Each node contains a routing table • Increased traffic on network due to sending updates to other nodes • Routing table used to determine best route Chapter 7: Network Concepts 20

  21. Chapter 7: Network Concepts 21

  22. Routing • Types of Routing • Static routing • Same route used from source to destination • Route is fixed • Data may not arrive if path is blocked • Dynamic (adaptive) routing • Route changes based on conditions on the network • The network software selects the best route • Broadcast routing • Transmit to all nodes in the network (flooding) Chapter 7: Network Concepts 22

  23. Chapter 7: Network Concepts 23

  24. Network Ownership • Private network • Built by a company for its own use • Public network • Built and owned by common carrier • Telephone network, ISPs, AOL • Virtual Private Network (VPN) • Private network that uses public carrier lines • Packet distribution network (PDN) • Use X.25 protocol • Packet-switching technology on public or private networks • Provide high-speed lines between nodes Chapter 7: Network Concepts 24

  25. Network Types • Local Area versus Wide Area Networks • Local Area Network (LAN) • Nodes in a small area • Campus, office, building • Widely used • Owned entirely by the organization in which it resides Chapter 7: Network Concepts 25

  26. Network Types • Local Area versus Wide Area Networks • Wide Area Network (WAN) • Nodes over a large area • Often uses common carrier lines • Originally developed for mainframe networks • Many functions taken over by LANs • Still exist for many applications Chapter 7: Network Concepts 26

  27. Chapter 7: Network Concepts 27

  28. Network Types • The Internet and Intranets • Internetwork (internet) • Refers to networks that are connected • Internet (uppercase I) • A specific, named network • World Wide Web • Intranet • Uses Internet technology on an internal network • Company calendars and forms may be posted Chapter 7: Network Concepts 28

  29. Chapter 7: Network Concepts 29

  30. Network Types • The Internet and Intranets • Access • Internet – open to anyone with proper access • Intranet – used only by selected people • Firewall – allows only authorized access to a network • Applications • Web pages (viewed using a Web browser) • John Deere (conversion of legacy systems) • Federal Express (customer access to shipping information) • Olivetti (employee collaboration over the Web) Chapter 7: Network Concepts 30

  31. Distributed Systems • Evolution from centralized to distributed systems • Definition of Distributed Systems • Systems with independent processing capability • Spread across multiple locations • Processors function independently • Components: hardware, operating system software, application software, data • Control is centralized or distributed • Data is centralized or distributed Chapter 7: Network Concepts 31

  32. Chapter 7: Network Concepts 32

  33. Chapter 7: Network Concepts 34

  34. Chapter 7: Network Concepts 35

  35. Chapter 7: Network Concepts 36

  36. Distributed Systems • Characteristics of Distributed Systems • Use smaller computers rather than large, centralized systems • Increased user involvement • Modular – an individual component can be easily replaced • User response time is faster • System is more flexible (uses many manufacturer’s equipment) Chapter 7: Network Concepts 37

  37. Chapter 7: Network Concepts 38

  38. Distributed Systems • Types of Distributed Systems • Distribution by Location • Hardware at many different geographic locations • Uses a network to communicate • Functions such as backup may not be done as required, due to lack of training • On-site specialists may be needed Chapter 7: Network Concepts 39

  39. Chapter 7: Network Concepts 40

  40. Distributed Systems • Types of Distributed Systems • Distribution by Function • Specific computers at different sites do different functions for the corporation • Individual departments have their own computers, isolated from other departments • May cause problems if data needs to be shared among departments Chapter 7: Network Concepts 41

  41. Chapter 7: Network Concepts 42

  42. Distributed Systems • Types of Distributed Systems • Distribution by Control • Refers to management of programmers and data • Creation of application programs may need to rely on data from another department • Systems need to work together Chapter 7: Network Concepts 43

  43. Distributed Systems • Types of Distributed Systems • Distribution by Processing • System designed around how data is processed • Processing of data is done at many sites • Hierarchical distributed system (Vertical system) • Some processing on central computer, some done at a remote, smaller computer • Horizontal distributed system (Peer computers) • Computer systems are equal Chapter 7: Network Concepts 44

  44. Chapter 7: Network Concepts 45

  45. Chapter 7: Network Concepts 46

  46. Chapter 7: Network Concepts 47

  47. Chapter 7: Network Concepts 48

  48. Distributed Systems • Implementation of Distributed Systems • File Handling • Distributed File System (DFS) is software used • Location independence means any application program can access data, no matter where it resides • Different architectures and operating systems must allow access to the data • Must overcome contention on the network for file access • Security of the file is also handled by the DFS • Maintains file directory of all files in system Chapter 7: Network Concepts 49

  49. Distributed Systems • Data Distribution • Data may be stored in files or databases • Single storage site in centralized configuration • Copies of data kept at remote sites • Local computers may have independent file systems • May create inconsistent data • Must synchronize all data periodically • Separate data systems cannot share data Chapter 7: Network Concepts 50

More Related