Topology means
structure. Hence, study of structural arrangement of elements or devices of
a network is called as network topology.
It is also known as
the layout of the network which depicts the geometric representation of all
the links and linking device of any network.
There are six major
network topologies that can be used for designing any network depending upon
the requirement.
Network Topology : Categorization
1. Network Topology :
Bus
Bus topology is also
called as a linear bus topology as it has the structure similar to as of
bus. It means, all the devices(including nodes) are connected together
thorough a single cable in linear fashion.
Transmitters are
used at the end of the linear cable as it is capable of absorbing noise and
data packets. If we do not use transmitters, the cable will act as a mirror
and a lot of noise will get generated. Below depicts the structure of a bus
topology.
Network Topology : Bus Topology
Advantages : Bus
Topology
Less cables are required.
Easy to install the setup.
Can be used for personal purpose
only.
Disadvantages : Bus
Topology
If there occurs a
break in the cable, entire network will get shutdown.
Difficult to find,
where the break in cable has occurred.
Expensive due to the
cost of transmitters.
We cannot use this
topology in large building organizations.
2. Network Topology :
Ring
To overcome
drawbacks of bus topology, concept of ring topology was introduced. In ring
topology, the structure of the network is formed similar to as of a “Ring”. Nodes are connected in a circular
manner to each other.
Only unidirectional
communication(Clockwise or Anticlockwise) can happen and not bidirectional.
For example: If node N1 wants to send data packet to node
N5, it has to pass through node N2, N3 and N4. This results in delay in
message passing and privacy is also affected.
Network Topology : Ring Topology
Advantages : Ring Topology
If there is a break in the cable, it does not
affect the entire network.
Problems can be easily
identified.
Devices/Nodes are easy to add or remove from
the network.
Disadvantages : Ring
Topology
Delay in message
passing due to the use of unidirectional concept.
No security of
data.
Privacy of data is
also hampered.
Use of lot of cables
increases the cost of entire network.
3. Network Topology :
Star
Start topology
overcomes the drawbacks of ring topology. In this, all the nodes/devices are
connected to a centralized device known as HUB in the structure similar to
that of a “STAR”.
It enables the
devices to send message directly to their respective
receivers.
Network Topology : Star Topology
Advantages : Star
Topology
Easily add and/or remove
devices.
Problem identification is
easy.
Data communication is fast due to the HUB
connectivity.
Disadvantages : Star
Topology
Expensive due to the
cost of cables and HUB.
If HUB fails(Due to
high load), entire network will shut down.
4. Network Topology :
Tree
In tree topology, the whole
structure relies on the “Backbone Cable(Optical
Fiber)”. Tree topology
is also known as expanding network topology.
Each node is
connected to a HUB just like in start topology and each HUB is connected to
each other via the backbone cable just like the bus topology. Hence we can
say that, Tree topology is the combination of Bus and Start topology which
includes their respective advantages and disadvantages too.
Network Topology : Tree Topology
Advantages : Tree
Topology
Point-to-Point
network.
Can be used in large
building organizations because of its network expanding
ability.
Disadvantages : Tree
Topology
Highly
expensive.
As tree topology
depends upon the backbone cable, any fault in that will shutdown the entire
network.
Complex
installation.
Even more complex
maintenance.
5. Network Topology :
Mesh
In Mesh Topology, each node provides an
individual link to another node. It means, every node in the entire network
is directly connected to every other node in the network making it the most
complex topology among all the other topologies.
Network Topology : Mesh Topology
Advantages : Mesh
Topology
Reduction in traffic
due to individual node.
Data communication
speed is fast.
Security and privacy
of data is provided.
Any fault in the
network doesn’t affect the entire network.
Disadvantages : Mesh
Topology
Most expensive
topology due to the amount of cables and HUBs used.
Highly complex
structure.
7. Network Topology :
Hybrid
Hybrid topology is a
custom topology. It is a combination of three or more standard topology
including Bus, Ring & Star topology. Every new combination of anyone of
these results in new topology every time.
Hybrid Topology =
Combination of( Bus + Star + Ring)
Topology.