9. Topologies - Structure
ď‚ź Star
– All the network devices connected to a central computer which
is often used as the file server
ď‚ź Ring
– Each of the devices on the network is connected in a ring or a
loop. (Each machine has a connection to the one previous and
the one after it in the loop)
ď‚ź Bus
– Each of the devices is connected directly to a main
communications line, called a bus
ď‚ź MESH
– All the computers connected to each other
Click here to view animations on topologies
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11. Star: Advantages and Disadvantages
ď‚ź Advantages of a Star
– If one cable fails the other stations are not affected
– Consistent performance even under heavy use
– Reliable market proven system
– No problems with collisions of data since each station
has its own cable to the server
– Easy to add new stations without disrupting the network
ď‚ź Disadvantages of a Star
– May be costly to install because of the cable lengths
required
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13. Bus: Advantages and Disadvantages
ď‚ź Advantages of a Bus
– Easy and inexpensive to install as it requires the
least amount of cable of the network types
– Easy to add more stations without disrupting
the network
ď‚ź Disadvantages of a Bus
– The whole network goes down if the main cable
fails at any point
– Cable failure is difficult to isolate
– Network performance degrades under a heavy
load
– Information can be transmitted in either
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15. Ring: Advantages and Disadvantages
ď‚ź Advantages of a Ring
– No dependence on a central computer or file server and
each node controls communication to and from itself
– Transmission around the network is one way only
– High data transmission rates are possible
ď‚ź Disadvantages of a Ring
– If one node breaks down transmission is disrupted
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17. Mesh: Advantages and Disadvantages
ď‚ź Advantages of a MESH
– Communication is not disrupted
– Alternative routes to node points/machines
– Security – packages can arrive/be sent via many
different routes
– Backup – with multiple connections it is easier to
distribute the data in case of disaster
ď‚ź Disadvantages of a MESH
– Cost
• of cables required to link machines together
• Of machines – similar spec machines required at
each location to be able to take over
– Difficult to install and reconfigure
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