A computer network connects two or more computers to share information. Network topology refers to how the nodes in a network are linked. There are several common topologies including ring, star, bus, and star-ring. A ring topology connects nodes in a closed loop where data travels in one direction. A star topology connects all nodes to a central hub. A bus topology uses a single cable to connect all nodes. A star-ring topology combines stars and a ring for flexibility. Key considerations in choosing a topology include costs, cable length needs, support for future growth, and cable type.

2. WHAT IS COMPUTER NETWORK?
 A computer network is a network in which two or more computers are connected with each
other so that they can share information or data with each other.

3. WHAT IS NETWORK TOPOLOGY?
 The art of connecting different computers in a network is known as
Topology.
 The term network topology refers to the way in which the nodes (Computer
or other devices that need to communicate) of a network are linked
together.
 It determines the data paths, which may be used between any pair of nodes
in the network.

4. RING TOPOLOGY
 The workstations in a ring topology
are connected in the shape of a
closed ring.
 Data is simply passed around from
one workstation to another.
 The data travels only in one
direction in a ring and cannot be
reversed back.
 Each workstation passes the data
onto the next one in the line
automatically.
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5. ADVANTAGES AND DISADVANTAGES OF RING TOPOLOGY
Disadvantages
 It requires more
complicated control
software.
 Data flows only in one
direction.
 If one node or
computer fails, the
entire network gets
affected.
Advantages
 The ring works well
where there is not
central-site computer
system.
 It covers a great
distance.
 It is more reliable than
a star network.

6. STAR TOPOLOGY
 In a star topology, all the
workstations are connected to a
central device called a HUB.
 The hub controls traffic on the
network.
 If the hub breaks down, the
network will not function.
HUB

7. ADVANTAGES AND DISADVANTAGES OF STAR TOPOLOGY
Disadvantages
 The system crucially
depends on the
Central Hub. If hub
fails, the entire network
fails.
 The system use large
amount of cabling.
Advantages
 If any of the local
computer fails, the
remaining portion of
the network is
unaffected.
 Its easy to identify an
error if the network is
not working.
 New computers can be
easily added.

8. BUS TOPOLOGY
 In the bus topology, there is a single bus
which carries all the data on the network.
 A bus is a single continuous cable to which
all the computers are connected.
 All the devices in a network are connected
to a single continuous cable called the Bus.
Backbone

9. ADVANTAGES AND DISADVANTAGES OF BUS TOPOLOGY
Disadvantages
 It offers limited flexibility
for change.
 A signal on the bus must
be strong enough to
reach the receiver.
 Hardware error are
difficult to detect.
Advantages
 Its quite easy to set up.
 Failure of one station
does not affect the rest of
the network.
 Uses the least amount of
cable.

10. STAR-RING TOPOLOGY
 This topology is combined to
achieve the best of both star and
ring topology.
 It consist of a number of
concentration points connected
together in a ring.
 The star-ring topology operates
exactly as the normal ring but
the physical wiring is arranged as
a series of interconnected stars.

11. CONSIDERATION WHEN CHOOSING A TOPOLOGY
 Money – A bus may be the least expensive way to install a network.
 Length of cable needed – The bus network uses shorter length of cable.
 Future growth – With star topology, expanding a network can be easily done.
 Cable type – The most common cable used in schools is Unshielded Twisted Pair,
which is often used with star topologies.