Computer Network

3 Key excerpts on "Computer Network"

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  eBook - ePub

  Mechatronics

  An Introduction

  • Robert H. Bishop(Author)
  • 2017(Publication Date)
  • CRC Press

    (Publisher)

  As computers became more powerful, there were many other applications that surfaced. The most visible application was the amount of information users started sharing among themselves. The volume of information being exchanged among users has been growing exponentially over the last three decades. As users needed to exchange such a mammoth amount of information, new techniques were invented to facilitate the process. There was not only a need for users to exchange information with others in an asynchronous fashion, there was also a need for computers to exchange information among themselves. The information being exchanged in this fashion has different characteristics than the information being exchanged through the telephone systems. This need led to the interconnection of computers with each other and that is what is called Computer Networks.

  17.3 Computer Networks

  A Computer Network is an interconnection of computers. The interconnection forms a facility that provides reliable and efficient means of communication among users and other devices. User communication in Computer Networks is assisted by computers, and the facility also provides communication among computers. Computer Networks are also referred to as computer communication networks. Interconnection among computers may be via wired or wireless transmission medium [5,6,10,13,18]. There are two broad categories of Computer Networks:

  FIGURE 17.3 (a) A typical wide area computer communication network. (b) A typical local/metropolitan area communication bus network. (c) A typical local/metropolitan area communication ring network.

  • Wide area networks
  • Local/metropolitan area networks

  Wide area Computer Networks, as the name suggests, span a wider geographical area and essentially have a global scope. On the other hand, local/metropolitan area networks span a limited distance. Local area networks are generally confined to an industrial building or an academic institution. Metropolitan area networks also have limited geographical scope but it is relatively larger than that of the local area networks [19]. Typical wide and local/metropolitan area networks are shown in Figure 17.3

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  eBook - ePub

  Information Technology

  An Introduction for Today's Digital World

  • Richard Fox(Author)
  • 2020(Publication Date)
  • Chapman and Hall/CRC

    (Publisher)

  6

  Computer Networks

  In this chapter, we study Computer Networks in several different ways. We look at the hardware that makes up Computer Networks. We examine network topologies and types followed by network protocols and protocol stacks, emphasizing both TCP/IP and the OSI model. We explore the Internet and related topics. The learning objectives of this chapter are to be able to:

  •  Describe and compare the various forms of hardware that make up Computer Networks •  Differentiate between network topologies in terms of use, strengths, and weaknesses •  Explain the roles of the protocols that make up the TCP/IP protocol stack and compare them to the roles proscribed by the OSI model •  Describe how the Internet works, including the various types of applications implemented to facilitate Internet communication

  Note that one important topic, network security, is not covered here. Instead, we look at computer security, including network security, in Chapter 9 .

  6.1      NETWORK TERMINOLOGY AND CONCEPTS

  A Computer Network is a collection of computers and computer resources. This is a purposefully vague definition. As we will see, there are many different types of Computer Networks. We connect the computers and resources together so that the collection of connected computers can share the resources. Additionally, the computers are connected together to provide communication between them and more importantly, the users of those computers. Resources might include printers, file servers, optical drive readers, magnetic tape storage devices, and so forth.

  In a network, we define the computer as being local or remote. The local computer is the computer that the user is using. The remote computer

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  eBook - ePub

  Foundations of Computer Technology

  • Alexander John Anderson(Author)
  • 2020(Publication Date)
  • CRC Press

    (Publisher)

  11.  Communication Standards: To ensure that the computers within a LAN can process the data passed among or between them a strict communications standard must be enforced. Standard communication systems such as Ethernet have become extremely important in linking small computers together into LANs.

  There are also now many different types of networks that can be connected together to form complex interlinked communication systems. Some of these are shown in Table 12.1 .

  Table 12.1Different types of communication networks.

  Network	Description
  1.	Wide area networks	Resources distributed over a large area such as a city or even a country.
  2.	Local area networks	Resources situated in the same building or factory site.
  3.	Cellular radio networks	Messages sent through various radio communication cells.
  4.	Global networks	The most common of the global networks is probably the telephone system which carries the bulk of data communication traffic over a country or continent wide area.
  5.	Satellite networks	Usually reserved for transcontinental messages.

  With all these different forms of networks, a computer system can no longer be regarded as a stand alone piece of equipment but, for maximum flexibility, must be designed to incorporate facilities to allow access to these open communication highways.

  12.1  LOCAL AREA NETWORK (LAN)

  With the decreasing cost of minicomputers it is now more economically viable for large organizations to base their computing system on a distributed philosophy rather than on a large central mainframe. This allows the computing power to be dispersed to the point of need, thereby giving the user instant access to powerful computing facilities without the inherent slow response of a large time shared mainframe.

  The most widely used form of communication network to link locally dispersed computers is the LAN. The first LAN, called the ARCnet, appeared in 1977 and was released by Datapoint Corporation. It could transmit data at 3 Mbps over a coaxial cable (Article 10.1 gives the main features of a LAN).

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