Download PowerPoint Lesson 23 - ICT-IAT

Living Online Module
Lesson 23 — Networks and
Telecommunication
Computer Literacy BASICS
Objectives
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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.
Computer Literacy BASICS
Objectives (cont.)
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Describe communications hardware.
Describe network architecture.
Describe communications software.
Computer Literacy BASICS
Vocabulary
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Bridge
Client
Client/server
network
Communications
channel
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Extranet
Gateway
Hub
Intranet
Computer Literacy BASICS
Vocabulary (cont.)
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Modem
Network interface
cards (NICs)
Peer-to-peer
network
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Router
Server
Transmission
media
Computer Literacy BASICS
Networks
A network is a group of two or more computers
linked together.
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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.
Computer Literacy BASICS
Networks (cont.)
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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).
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Most WANs are made up of several LANs.
The transmission of data from one location to
another is called data communications.
Computer Literacy BASICS
Components Required for
Data Communications
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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
Computer Literacy BASICS
Communications Components
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Computer Literacy BASICS
Network Benefits
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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.
Computer Literacy BASICS
Communications Media
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Sending data from one computer to another
requires a channel, the link through which
the message is sent.
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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.
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A phone line or cable serves as a channel.
A modem is a conversion device.
Computer Literacy BASICS
Transmission Media
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Sending a message through the channel
requires a transmission media, which can be
physical or wireless.
Examples of physical media include twistedpair cable, coaxial cable, and fiber-optic cable.
Examples of wireless media include radio
signals, microwave signals, and satellite
transmissions.
Computer Literacy BASICS
Types of Physical Media
Twisted-pair cable
Coaxial cable
Fiber-optic cable
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Computer Literacy BASICS
Types of Wireless Media
Satellite transmissions
Microwave towers
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Computer Literacy BASICS
Network Hardware
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Most networks consist of a server and
multiple client computers.
They also include two other categories of
hardware:
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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.
Computer Literacy BASICS
Communications Hardware
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A modem converts analog signals to digital and
vice versa.
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Cable modems use coaxial cable to send data
over cable television lines.
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Modems enable a computer to send data over a
standard phone line.
The sending computer and the receiving computer
must both have modems.
These have much faster transmission rates than a
standard telephone line modem.
Computer Literacy BASICS
Communications Hardware:
A Computer with Attached Modem
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Computer Literacy BASICS
Network Transmission Hardware
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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
Computer Literacy BASICS
Network Transmission Hardware:
Computers Connected to a Hub
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Computer Literacy BASICS
Local Area Networks
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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
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Client/server
Peer-to-peer
Computer Literacy BASICS
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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Computer Literacy BASICS
A Peer-to-Peer Network
All of the computers
on a peer-to-peer
network are equal—
there is no server,
and people on the
network each determine what files they
will share with others
on the network.
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Computer Literacy BASICS
Wide Area Networks
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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
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Intranets
Extranets
Computer Literacy BASICS
Intranets
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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.
Computer Literacy BASICS
Extranet
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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).
Computer Literacy BASICS
Network Operating Systems
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Networks require a network operating system
(NOS) and a desktop operating system.
The NOS runs on the server and provides
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Network administration tools
Print services
Client services
Security services
Computer Literacy BASICS
Summary
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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.
Computer Literacy BASICS
Summary (cont.)
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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.
Computer Literacy BASICS
Summary (cont.)
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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.
Computer Literacy BASICS
Summary (cont.)
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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.
Computer Literacy BASICS
Summary (cont.)
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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.
Computer Literacy BASICS