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Introduction

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  • 1. CS3505: The Internet and the Information Highway INTRODUCTION
  • 2. CS3505 Objectives
    • make better use of the Internet
    • make better use of all telecom, data networks
    • understand basic Internet architecture
    • background, evolution of Internet
  • 3. CS3505 Admin details
    • lab assignments and homeworks required for passing grade
    • class participation required, important part of class
    • exam or graded homework, project for letter grade
  • 4. introduction: CS3505
    • network examples
    • network definitions
    • classifications of networks
    • layered models (high level)
    • purposes of networks
    • network industries and standards
    • communication protocols
  • 5. Examples of Networks
    • telephone networks
    • LANs : ethernet, token ring
    • ARPANet/MILNET WANs
    • Cable TV networks
    • Cellular phone networks
    • The INTERNET
  • 6. network definitions
    • network - 2 or more machines connected, sending data to other, using common media and protocols
    • computer network - network of computers
    • distributed network - tightly connected, common purpose network. e.g. airline reservation system, real-time battle simulations
  • 7. network definitions
    • LAN, MAN, WAN (local, metro, wide area networks)
    • integrated network - different types of traffic (voice, video, email)
    • internetwork/Internet - interconnected networks using TCP/IP protocol
  • 8. more network definitions
    • intranet - (1) a network internal to an organization, used to connect its clients; (2) a network of nodes separated from the external world by a firewall (ex. NPS Internet)
    • extranet - a network using the Internet to connect a set of users, operating over a VPN (virtual private network); uses web-browser technology and the Internet to connect a private community of users (ex. private newsletter using Internet; stock-broker)
  • 9. network classifications
    • geographical coverage (LAN ... WAN)
    • topology (geometry of links)
    • switching technique
    • speed (data rates)
    • data/information content
  • 10. geographical coverage
    • LAN: Local Area Networks
      • simpler, less software layers
      • higher data transfer rates (generally)
      • simple routing
      • IEEE standards
      • easily connected via bridges
      • examples: ethernet, token ring
  • 11. geographical coverage
    • MANs
      • traditional category
      • cable TV, local phone
      • DQDB, FDDI
      • less used, as most networks can be classified into LAN/WAN
  • 12. geographical coverage
    • WANs
      • data speeds slower, in general (this distinction fading)
      • national, international boundaries
      • includes internetworking
      • ARPANet first example
      • much more complex software
      • OSI model
  • 13. network topologies
      • star
      • ring
      • bus
      • fully connected
      • tree
      • mesh
  • 14. switching techniques (4)
    • (1) broadcast
      • no switching or routing; 1 station transmits, all others can receive
      • collisions occur if more than 1 attempts to transmit at once
      • examples: ethernet LAN and radio networks, satellites (to some degree)
  • 15. switching techniques
    • (2) circuit switching
      • 3 distinct phases
      • traditional voice network
      • nice for user, but inefficient use of transmission facilities
      • served traditional voice networks well, but gradually becoming outdated by new technology
  • 16. switching techniques
    • (3) packet switching
      • fixed packet size
      • much more efficient use of facilities
      • several refinements; fast packet switching (ATM) is culmination
  • 17. switching techniques
    • (4) message switching
      • sends entire message as single transmission
      • efficiency problems from unbound message size
  • 18. network model: ISO 7-layers
    • designed 1970; still heavily used
    • 7 layer model
      • 1 physical layer
      • 2 data link layer
      • 3 network layer
      • 4 transport layer
      • 5 session layer
      • 6 presentation layer
      • 7 application layer
  • 19. modified ISO model
    • 1 physical layer - moves a bit from a to b using a physical(electrical, optical, etc.) signal
    • 2 data link - groups bits into frames, or messages, for error control and information
  • 20. modified ISO model
    • 3 network layer - moves packets through the network
    • 3.5 internet layer - routes packets from network to network
  • 21. modified ISO
    • 4 transport - end to end; interface between user apps and the network/internet
    • 7 application - user interface to network, and user services: email, file transfer, world wide web, etc.
  • 22. IEEE LAN model
    • specifically for LAN networks
    • changes in data link, physical layers; others same
    • layers:
      • physical - similiar but special for LANs
      • MAC: media access control; replaces d.link
      • LLC: logical link control
  • 23. purposes of networks
    • resource sharing
    • increased reliability
    • efficiency
    • communications
    • future applications: voice, video, data, images, appliances, .... ?
  • 24. basic network services
    • e-mail
    • file transfers (ftp, etc)
    • remote login (rlogin, telnet)
    • WWW (web)
  • 25. basic network services
    • telephone/voice
    • instant messages
    • intranets
    • extranets
  • 26. network ing industry
    • originally two separate, different industries - computers/communications
    • computer: IBM, DEC, Sun, Apple, Cray, SGI, Compaq, Dell, Gateway, Microsoft, etc
    • communications: AT&T, Sprint, MCI-WorldCom, RBOCs, GTE, other phone companies, etc.
  • 27. network ing industry
    • 2 industries have been merging
    • signs of the merging
      • initial purpose of each
      • signals
      • importance of each to the other
      • research labs
      • Sun’s logo “the network is the computer”
  • 28. industry sectors
    • Computer Industry
      • mainframes, “big” computers - IBM, Cray
      • mid-size, workstations - Sun, SGI, (DEC, Tandem)
      • personal computers (manufacturers) -Compaq, Dell, Gateway
      • PCs - software - Microsoft, Apple
      • semiconductors for PCs - Intel, AMD
  • 29. industry sectors
    • Communications
      • long distance telephone (ATT, Sprint)
      • local telephone (Pacific Bell, etc.)
      • telecom. equipment (Lucent, Nor. Telecom)
      • internet service providers (AOL, etc)
      • radio, wireless data, satelite, etc
  • 30. standards for networks
    • reasons for standards
    • advantages
    • disadvantages
    • standards organizations
  • 31. communication protocols
    • protocol: the algorithm or procedure used for communication between processes at the same layer
    • examples: telephone call; e-mail
    • protocol processes make use of lower layers as a service.
    • heart of communications process
  • 32. communication protocols
    • some things protocols do
      • bit interpretation to signals
      • group bits into messages
      • error detection and correction
      • synchronization
      • make more efficient use of networks facilities
  • 33. communication protocols
    • three basic phases of data communications
    • 1. connection establishment
    • 2. data transfer
    • 3. connection termination
    • connection-oriented/connectionless