A computer network connects computers to share information and resources. There are different topologies that define how computers are physically connected in a network, including bus, star, ring, and mesh. Bus topology connects all computers to a single cable but failure of the cable shuts down the whole network. Star topology connects each computer to a central hub, allowing individual failures without network shutdown. Ring topology is like a bus but with the first and last computers connected, using tokens for communication. Mesh combines star and ring for greater reliability but at higher cost. The optimal topology depends on network size and needs.

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2. Computer Networks
• A computer network is basically a collection of
computers which are connected to each other. It is
an interconnection of computers for the purposes
of sharing information and resources.
• A popular example of a computer network is the
internet, which allows millions of users to share
information.
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3. An example of a network
Router
Hub
Bridge
Cable Node
Hub
Internet
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4. TOPOLOGY
There are certain rules or methods so as to
connect the computers to each other.
Hence, here the word TOPOLOGY exists.
A Topology is a map of computer which
allows how to connect computers with each
other.
It is a physical connection of computers
within a particular network.
It defines the nodes and cables that
together makes up a network.
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5. Types of Topology
Generally, there are 3 types of topologies. They are :-
 Bus Topology
 Star Topology
 Ring Topology
Now besides these 3 topologies, there is one more
topology named as Mesh Topology which is the
combination of star and ring topology. It comes
under Hybrid Networks.
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6. Network Topologies
1. Bus Topology
– In this network, all computers are connected through single
cable and all the nodes or computers do transmission and
reception of messages or data using single cable.
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7. Bus Topology
Advantages Disadvantages
Such networks is easy to The failure of the cable
build and install. brings the whole network
It is inexpensive and easy to shut down.
to use it. At a time, only 1 node can
If one node fails, others are transmit signals due to
not affected. which the communication
becomes slow.
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8. 2. Ring Topology
– The ring network is like a bus network, but the “end” of the
network is connected to the first node.
– Nodes in the network use tokens to communicate with each
other.
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9. Ring Topology
Advantages Disadvantages
Ring networks are Failure of one computer
moderately easy to install. affects the whole network.
Cable faults are easily Adding or removing
located making computers is difficult to
troubleshooting easier. achieve.
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10. 3. Star Topology
 Each node is connected to a device in the center of the
network called a hub.
 The hub simply passes the signal arriving from any node to the
other nodes in the network.
 The hub does not route the data.
Hub
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11. Star Topology
Advantages Disadvantages
Failure of the central hub
The failure of a single
causes the whole network
computer or cable does not
to shut down.
bring down the entire
network. It is slightly expensive
than Bus Topology.
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12. 4. Mesh Topology
– Mesh topology is the combination of star and ring topologies.
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13. Mesh Topology
Advantages Disadvantages
It is more reliable than It is very expensive.
compared to other It includes lots of nodes
topologies. and cables for connections.
Data can be transmitted Due to this, adding or
easily even if there is a removing of nodes is
heavy traffic within the difficult to attain.
network.
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14. Recommendations
For single or a small group of users, it is suggested to
use a bus or ring topology as it is cheap and easy to
install and use.
For a company or a big organization, it is better to fix
mesh or star topology. Although it is an expensive
network but, it will yield good and satisfying
performance.
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15. Conclusion
Hence, we can say that a topology is geometric
representation of the relationship of all the linking
devices to one another. Despite having some merits
and demerits, these various topologies can be utilized
according to the user’s needs and desires.
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16. Acknowledgement
Website - www.wikipedia.com
Data Communications And Networking - by
Behrouz A. Forouzan
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