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Introduction to Computer Networks

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Data Communications and Computer Networks: A Business User s Approach Third Edition Chapter 1: Introduction to Computer Networks and Data Communications – PowerPoint PPT presentation

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Title: Introduction to Computer Networks


1
Data Communications and Computer Networks A
Business Users Approach Third Edition
  • Chapter 1
  • Introduction to Computer Networks
  • and Data Communications

2
Objectives
  • After reading this chapter, you should be able
    to
  • Define the basic terminology of computer networks
  • Recognize the individual components of the big
    picture of computer networks
  • Outline the basic network configurations
  • Cite the reasons for using a network model and
    explain how they apply to current network systems

3
Objectives (continued)
  • List the layers of the OSI model and describe the
    duties of each layer
  • List the layers of the TCP/IP protocol suite and
    describe the duties of each layer
  • Compare the OSI model and TCP/IP protocol suite
    and list their differences and similarities

4
Introduction
  • Who today has not used a computer network?
  • Mass transit, interstate highways, 24-hour
    bankers, grocery stores, cable television,
    cellular telephones, most businesses and schools,
    and other retail outlets can support some form of
    computer networks

5
The Language of Computer Networks

  • Computer network - an interconnection of
    computers and computing equipment using either
    wires or radio waves over small or large
    geographic distances
  • Local area network - networks that are small in
    geographic size spanning a room, building, or
    campus
  • Metropolitan area network - networks that serve
    an area of 3 to 30 miles - approximately the area
    of a typical city

6
The Language of Computer
Networks
  • Wide area network - a large network that
    encompasses parts of states, multiple states,
    countries, and the world
  • Data communications - the transfer of digital or
    analog data using digital or analog signals
  • Voice network - a network that transmits
    telephone signals
  • Data network - a network that transmits computer
    data

7
The Language of Computer Networks
(continued)

  • Telecommunications - the study of telephones and
    the systems that transmit telephone signals
  • Network management - the design, installation,
    and support of a network and its hardware and
    software
  • Personal area network a network of a few
    meters, between wireless devices such as PDAs,
    laptops, and similar devices

8
The Big Picture of Networks
  • Networks are composed of many devices, including
  • Workstations (computers and telephones)
  • Servers
  • Network hubs and switches (bridges)
  • Routers (LAN-WAN and WAN-WAN)
  • Telephone switching gear

9
The Big Picture of Networks (continued)


10
Computer Networks - Basic Configurations

  • Computer terminal/microcomputer to mainframe
    computer
  • Microcomputer to local area network
  • Microcomputer to Internet
  • Local area network to local area network
  • Personal area network to workstation

11
Computer Networks Basic Configurations (co
ntinued)
  • Local area network to metropolitan area network
  • Local area network to wide area network
  • Sensor to local area network
  • Satellite and microwave
  • Wireless telephone and wired telephone to network

12
Terminal/microcomputer-to-mainframe
Computer Configurations
  • Predominant form in 60s and 70s
  • Still used in many types of businesses for data
    entry and data retrieval
  • Usually involves a low-speed connection

13
Terminal/microcomputer-to-
mainframe Computer Configurations
(continued)

14
Microcomputer-to-Local Area Network

  • Highly common throughout business and academic
    environments, and now even homes
  • Typically a medium- to high-speed connection
  • Microcomputer requires a NIC (network interface
    card)
  • NIC connects to a hub-like device

15
Microcomputer-to-local Network
Configurations (continued)

16
Microcomputer-to-Internet Configurations

  • Very popular with home users and some small
    businesses
  • Typically, a dial-up modem is used to connect
    users microcomputer to an Internet service
    provider
  • Newer technologies such as DSL and cable modems
    are replacing modems

17
Microcomputer-to-Internet
Configurations
(continued)

18
Local Area Network-to-Local Area Network
Configurations (continued)
  • Found in businesses and schools that have two or
    more LANs and a need for them to intercommunicate
  • A bridge-like device (such as a switch) is
    typically used to interconnect LANs
  • Bridge-like device can filter frames

19
Local Area Network-to-Local Area Network
Configurations (continued)

20
Personal Area Network-to-Workstation
Configurations
  • Interconnects wireless devices such as PDAs,
    laptops, and music playback devices
  • Used over a short distance such as a few meters

21
Personal Area Network-to-Workstation
Configurations (continued)

22
Local Area Network-to-Metropolitan Area
Network Configurations
  • Used to interconnect companies (usually their
    local area networks) to networks that encompass a
    metropolitan city
  • High speed networks with redundant circuits

23
Local Area Network-to-Metropolitan Area
Network Configurations (continued)


24
Local Area Network-to-Wide Area Network
Configurations
  • One of the most common ways to interconnect a
    user on a LAN workstation to the Internet (a wide
    area network)
  • Router
  • Typical device that performs LAN to WAN
    connections
  • More complex devices than bridges/switches

25
Local Area Network-to-Wide Area
Network Configurations (continued)


26
Wide Area Network-to-Wide Area Network
Network Configurations
  • High-speed routers and switches are used to
    connect one wide area network to another
  • Thousands of wide area networks across North
    America
  • Many interconnected via these routers and
    switches

27
Sensor-to-Local Area Network
Configurations
  • Not all local area networks deal with
    microcomputer workstations
  • Often found in industrial and laboratory
    environments
  • Assembly lines and robotic controls depend
    heavily on sensor-based local area networks

28
Sensor-to-Local Area Network
Configurations (continued)

29
Satellite and Microwave Configurations

  • Long distance wireless connections
  • Many types of applications including long
    distance telephone, television, radio, long-haul
    data transfers, and wireless data services
  • Typically expensive services but many companies
    offer competitive services and rates

30
Satellite and Microwave Configurations
(continued)

31
Wireless Telephone Configurations

  • Constantly expanding market across the U.S. and
    world
  • Second generation PCS services available in most
    areas and under many types of plans
  • Next generation services beginning to replace
    PCS phones

32
Wireless Telephone Configurations
(continued)

33
Wireless Telephone Configurations
(continued)
  • An additional basic configuration is telephone
    to network
  • Telephone systems are ubiquitous and can now
    carry more data than voice
  • Common configuration telephone connected to
    POTS
  • Newer configuration telephone to LAN via
    gateway (VoIP)

34
Network Architectures
  • Reference model that describes the layers of
    hardware and software necessary to transmit data
    between two points or for multiple devices /
    applications to interoperate
  • Reference models are necessary to increase the
    likelihood that different components from
    different manufacturers will converse
  • Two architectures are required learning The OSI
    Model, and the TCP/IP protocol suite

35
The Open Systems Interconnection
(OSI) model

36
The Open Systems Interconnection
(OSI) model (continued)
  • Application layer - where the application using
    the network resides
  • Common network applications include remote login,
    file transfer, e-mail, and web page browsing
  • Presentation layer - performs series of
    miscellaneous functions necessary for presenting
    the data package properly to the sender or
    receiver

37
The Open Systems
Interconnection (OSI) model (continued)
  • Session layer - responsible for establishing
    sessions between users
  • Transport layer - provides end-to-end error-free
    network connection
  • Makes sure data arrives at destination exactly as
    it left the source
  • Network layer - responsible for creating,
    maintaining and ending network connections
  • Transfers a data packet from node to node within
    the network

38
The Open Systems Interconnection
(OSI) model (continued)
  • Data link layer - responsible for taking data and
    transforming it into a frame with header, control
    and address information, as well as error
    detection code
  • Physical layer - handles the transmission of bits
    over a communications channel
  • Includes voltage levels, connectors, media
    choice, modulation techniques

39
The Open Systems Interconnection (OSI)
model (continued)

40
The TCP/IP Protocol Suite

41
The TCP/IP Protocol Suite (continued)
  • Application layer - equivalent to the OSIs
    presentation and application layers
  • Transport layer - performs same function as OSI
    transport layer
  • Network (Internet or internetwork) layer -
    roughly equivalent to the OSIs network layer
  • Network access (data link/physical) layer -
    equivalent to the OSIs physical and data link
    layers

42
Logical and Physical Connections
  • Logical connection exists only in the software
  • Physical connection exists in the hardware
  • In a network architecture
  • Only lowest layer contains physical connection
  • All higher layers contain logical connections

43
Logical and Physical Connections
(continued)

44
Logical and Physical Connections
(continued)

45
Network Configurations in Action

46
The TCP/IP Protocol Suite in Action
  • Note the flow of data from user to web browser
    and back
  • At each layer, information is either added or
    removed
  • Depends on whether data is leaving or arriving
    at a workstation
  • Encapsulation - adding information over
    pre-existing information

47
The TCP/IP Protocol Suite in Action
(continued)

48
Summary
  • Basic terminology of computer networks
  • Individual components of computer networks
  • Basic network configurations
  • Network models and how they apply to current
    network systems
  • Layers of the OSI model and the TCP/IP protocol
    suite
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