Transcript Networks - The Ecclesbourne School Online

Networks
Mr Hewitt
Objectives
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By the end of this lesson you will be
able to:
Compare stand alone, networked and
laptop computers
Define a Network
Explain the terms LAN and WAN
Understand network topology
Types of computer
CAN YOU GIVE A DEFINITION OF EACH?
Stand alone PC
A PC that is not
connected to any
other computer
Laptop PC
Network
A lightweight
portable
computer
A collection of
computers linked
together
What is a Network?
Stand alone PC
Network
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What is a Network
‘A collection of
computers are linked
together so they can
communicate’
‘Networked computers
can share hardware
software and data’
What is a LAN
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LAN stands for a ‘Local Area Network’
The School network is a LAN
All computers are in the same building
Computers are permanently connected
Each computer is a workstation
There is a server with applications software,
a list of users and passwords
Lans users need a password to log on
What are the advantages of
LAN’s?
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Shared software and peripherals e.g.
printers
Workstations can be lower spec
Centralised information storage
Users can communicate & share data
What are the disadvantages of
LAN’s?
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Security is needed to protect programs
A network technician is needed
Faults can affect all users
What is a WAN?
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WAN stands for Wide Area Network
Computers are spread over a large
area
Computers are linked by phone lines
radio or satellite links
The Internet is one big WAN
Computers are not permanently
connected
What are the advantages of
WAN’s
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Ease of communication
Access to information
Work from home
Advertising and E-business
What are the disadvantages of
a WAN?
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Viruses - need firewall
Lack of face to face interaction
Costly
Risk of data being intercepted
Line or Bus Networks
Good Points:
All data is sent to
and from the file
server along a
central line of
cable. All terminals
are connected to the
central line
Cheap – doesn’t
use much cable
Bad Points:
Can be slow as all data
goes down the central line
If the central cable fails,
the whole network goes
down
Ring Networks
Good Points
Terminals are linked in a
ring, data flows around
the network in one
direction only
Cheap to add
computers
Fast as data only flows
one way
Bad Points
The system gets slow when
there are lots of users
If the central cable fails the
whole network goes down
Star Networks
In a Star Network, a large number
of computers are directly
connected to the server
Good Points
Bad Points
If one computer or a cable
fails, the others will be
unaffected
If the central computer fails,
the whole network will go
down
This is the fastest network
Uses lots of cable so is
expensive
Wireless Networks
In a wireless network, there are
no wires!
Computers have a wireless
network card
The server will act as a base
station which will be able to
receive wireless transmission
of data