Living Online Module Lesson 23 Networks and Telecommunication

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Living Online ModuleLesson 23 Networks and
Telecommunication

• Computer Literacy BASICS

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Objectives

• Describe a network.
• Explain the benefits of a network.
• List and describe the types of networks.
• Explain the advantages and disadvantages of
  networked computing.
• List and describe communications media.

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Objectives (cont.)

• Describe communications hardware.
• Describe network architecture.
• Describe communications software.

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Vocabulary

• Bridge
• Client
• Client/server network
• Communications channel

• Extranet
• Gateway
• Hub
• Intranet

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Vocabulary (cont.)

• Modem
• Network interface cards (NICs)
• Peer-to-peer network

• Router
• Server
• Transmission media

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Networks

• A network is a group of two or more computers
  linked together.
• Most networks have a server that manages the
  network resources.
• Most networks have multiple clients, which are
  computers that access the server.
• An endpoint of a network connection, such as a
  computer terminal, server, or printer, is called
  a node.

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Networks (cont.)

• A network confined to a limited geographical area
  is called a local area network (LAN).
• A network spread over a wide area is called a
  wide area network (WAN).
• Most WANs are made up of several LANs.
• The transmission of data from one location to
  another is called data communications.

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Components Required for Data Communications

• A sending device, which is generally a computer
• A communications device, such as a modem, that
  converts the computer signal into signals
  supported by the communications channel
• A communications channel or path, such as
  telephone lines, cable, or a wireless
  transmission link, over which the signals are
  sent
• A receiving device that accepts the incoming
  signal, which is generally a computer
• Communications software

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Communications Components
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Network Benefits

• Networks provide almost instant communication
  with other users on the network.
• Users can share information.
• Users can share hardware.
• Users can share software.
• Users can work on group projects.

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Communications Media

• Sending data from one computer to another
  requires a channel, the link through which the
  message is sent.
• A phone line or cable serves as a channel.
• You also need a device on each end of the channel
  to convert the computer signal to a signal type
  that the channel can send.
• A modem is a conversion device.

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Transmission Media

• Sending a message through the channel requires a
  transmission media, which can be physical or
  wireless.
• Examples of physical media include twisted-pair
  cable, coaxial cable, and fiber-optic cable.
• Examples of wireless media include radio signals,
  microwave signals, and satellite transmissions.

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Types of Physical Media
Twisted-pair cable
Coaxial cable
Fiber-optic cable
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Types of Wireless Media
Satellite transmissions
Microwave towers
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Network Hardware

• Most networks consist of a server and multiple
  client computers.
• They also include two other categories of
  hardware
• Communications hardware to facilitate the
  transmitting and receiving of data
• Network transmission hardware to connect the
  cabling and amplify signals as they travel across
  the network.

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Communications Hardware

• A modem converts analog signals to digital and
  vice versa.
• Modems enable a computer to send data over a
  standard phone line.
• The sending computer and the receiving computer
  must both have modems.
• Cable modems use coaxial cable to send data over
  cable television lines.
• These have much faster transmission rates than a
  standard telephone line modem.

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Communications HardwareA Computer with Attached
Modem
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Network Transmission Hardware

• Network Interface Cards (NICs) All computers in
  a LAN must have a NIC, which enables and controls
  the sending and receiving of data between the
  computers.
• Hub Receives and sends signals back out
• Bridge Connects one LAN to another LAN
• Gateway Links networks using different protocols
• Router Connects multiple networks and determines
  the fastest route for sending data over the
  network

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Network Transmission HardwareComputers
Connected to a Hub
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Local Area Networks

• Local area networks (LANs) are usually confined
  to a limited area.
• Most LANs connect computers and peripherals, such
  as printers or scanners.
• The two most popular LANs are
• Client/server
• Peer-to-peer

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A Client/Server Network
A computer (or more than one computer) called a
server manages the network resources for all of
the devices on the network.
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A Peer-to-Peer Network
All of the computers on a peer-to-peer network
are equalthere is no server, and people on the
network each deter-mine what files they will
share with others on the network.
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Wide Area Networks

• Wide area networks (WANs) cover a large
  geographical area such as a city, a state, a
  country, or the world.
• Most WANs consist of two or more LANs connected
  by routers.
• Two types of WANs are
• Intranets
• Extranets

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Intranets

• An intranet is designed for the exclusive use of
  people within an organization.
• Many businesses have intranets that they use to
  make files, such as handbooks and employee
  manuals, newsletters, and employment forms,
  available to company employees.
• An intranet may use HTML files and browsers to
  create and view documents on the network.

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Extranet

• An extranet is similar to an intranet, but it
  allows specified users outside of the
  organization to access internal information
  systems.
• Like the Internet, extranets utilize and support
  Web technologies, such as hyperlinks and Web
  pages, coded in hypertext markup language (HTML).

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Network Operating Systems

• Networks require a network operating system (NOS)
  and a desktop operating system.
• The NOS runs on the server and provides
• Network administration tools
• Print services
• Client services
• Security services

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Summary

• A network is a group of two or more computers
  linked together.
• A local area network is generally confined to a
  limited geographical area.
• A wide area network is made up of several
  connected local area networks.
• Data communications is the transmission of data
  from one location to another.

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Summary (cont.)

• The Internet is the biggest network of all.
• You can use a network for information sharing,
  hardware sharing, software sharing, and as a
  collaborative environment.
• The link through which data is transmitted is the
  communications channel.
• Transmission media can be either physical or
  wireless.

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Summary (cont.)

• Physical media includes twisted-pair cable,
  coaxial cable, and fiber-optic cable.
• Wireless media includes radio signals,
  microwaves, and satellite transmission.
• Most networks consist of a network server and
  computer clients.
• A modem is a type of communication device.

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Summary (cont.)

• Network interface cards enable the sending and
  receiving of data between PCs in a LAN.
• A hub is a device that controls the incoming and
  forwarding of data.
• A bridge connects one LAN to another.
• A gateway links two different types of networks.

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Summary (cont.)

• A router directs traffic on the Internet or on
  multiple connected networks.
• The two popular types of LANs are the
  client/server network and the peer-to-peer
  network.
• Networks require network operating system
  software.