Network topology refers to the arrangement of elements like nodes, links and peripherals that form a communication network. The key types of network topologies include bus, star, ring, mesh and hybrid. Bus topology uses a single cable to connect all nodes but if it fails the whole network fails. Star topology connects all nodes to a central hub providing easier troubleshooting but a single hub failure disables the network. Ring topology connects each node in a circular fashion allowing orderly flow but a single node failure takes the whole network down. Mesh networks provide robust connectivity through redundant links but have higher implementation costs. Hybrid topologies combine two or more topologies to gain advantages while reducing disadvantages.

1. Network Topology

2. What is Network Topology?
 is the arrangement of the elements (links, nodes and peripherals) of a
communication network.
 is the topological structure of a network and may be depicted physically or
logically.
 It is an application of graph theory wherein communicating devices are
modeled as nodes and the connections between the devices are modeled
as links or lines between the nodes.

3. Importance of Network Topology
 It plays a significant role in the functioning of networks.
 It help us better understand the networking concepts.
 It also helps reduce the operational and maintenance costs such as cabling cost.
 It is a factor in determining the media type to be used to cable network.
 Error or fault detection is made easy using network topologies.

4. Network Topology classification
 Bus Topology
 Star Topology
 Ring Topology
 Mesh Topology
 Hybrid Topology

5. Bus topology
 Bus topology refers to a network setup where nodes or devices are interconnected using
a single cable. It is because of this setup why bus topology is often referred to as line
topology or backbone.
Backbone
or core is a part
of computer
network that
interconnects various
pieces of network,
providing a path for
the exchange of
information between
different LANs or
subnetworks.

6. Additional info
 Depending on the nodes or devices that need to be connected, a coaxial
cable or an RJ45 cable is typically used to connect the devices.
 Bus topology usually consists of two ends and signals travel from one end
to another. Bus topology is unidirectional and data is transferred from one
end to another in a single direction.

7. Advantages
 Cost-effective.
 Less cable required to connect the nodes.
 Very easy to understand.
 Provides an easy feasibility to extend or to reduce a network.
 Ideal for small network setups.

8. Disadvantages
 Ideal only for small network setups.
 If the backbone (primary) cable fails, the entire network fails.
 Unidirectional.
 Transmission speeds are drastically reduced with the increased number of
nodes.

9. Star Topology
 In a star topology, every node in the network is connected to a central
computer or a node, which takes care of the network. Every device in the
network has a direct connection to the central node and every node is
indirectly connected to other nodes using the central node.
Central Hub
central hub acts
as a conduit to
transmit
messages
When a hub receives a packet of
data (an Ethernet frame) at one of
its ports from a network device, it
transmits (repeats) the packet to all
of its ports to all of the other
network devices.

10. Additional info
 All the data in a star topology flow through the central hub before it
reaches its destination.
 The central hub manages and controls all data transfers and connectivity
in a star topology.
 The central hub also acts as a repeater to make sure there is zero or
minimal data loss during the transmissions. A star topology can be
configured using a twisted pair, coaxial cable, or an optical fiber.

11. Advantages
 Failure of one node will not affect the entire network.
 Devices can be added, removed, reconfigured, or modified without
disturbing the network.
 Less cabling is needed to configure star topology.
 Easy to set up and modify.
 Easy to troubleshoot.

12. Disadvantages
 The entire network is dependent on the central hub: If the hub fails, then
the whole network will be down.
 Expensive to install and use.
 Performance is solely based on the central hub’s configuration, power, and
efficiency.

13. Ring Topology
 a ring network topology forms a ring as each node or computer in a
network are connected to each other in a circular manner. Every node or
device in a ring topology will have exactly two neighbors and accordingly,
the last node in the network will be connected to the first node.
How do Ring
topology works?
Data travels from node to node, with each node along the way
handling every packet.

14. Additional info
 In a ring topology, all devices are connected in a closed loop configuration
and one node in the network acts as a monitor, which essentially takes
care of the configuration. In a ring topology, all the data packets are
transmitted from one node to another in a circular manner and, therefore,
for a data packet to reach one point to another it has to traverse through
all the intermediate nodes.

15. Advantages
 Performs better than bus topology under heavy network loads.
 Point-to-point connectivity of the nodes makes it easy to identify and
detect misconfigurations or faults.
 Orderly network flow.
 Cost effective to implement.

16. Disadvantages
 One malfunctioning node can collapse the whole network.
 Transmission line failure can take down the whole network.
 Communication delay is proportional to the number of nodes in a ring.
 Bandwidth is shared among all the devices in a network.
 Reconfiguring, adding, or removing nodes requires the network to shut
down.

17. Mesh Topology
 Mesh topology is a widely used network model that has a point-to-point
connection between each node in the network. Every node or a device in a
mesh network connects to other nodes directly and in a non-hierarchical
manner.

18. Data transmission based on two
important techniques
1. Routing
2. Flooding

19. Routing
 Every node in a mesh network can have a routing logic and transmission of
data or information happens through that routing logic. This routing logic
can be used to find the shortest distance to send some information from
sender to receiver or the logic can be used to avoid using broken lines for
data transmission.

20. Flooding
 In the case of flooding, the same data is transmitted to each node in the
network. Therefore, no routing logic is required in case of flooding mesh
networks. Loss of data is highly unlikely as every node will have the same
data with them. This makes it robust and fault-tolerant. However, this also
increases the load on the network.

21. Advantages
 Fully connected.
 Robust.
 Provides security and privacy.
 Any node failure won’t affect the network.
 Less load and collisions to dedicated lines.
 Isolation and fault-detection are easy.

22. Disadvantages
 Cost of implementing and cost of cabling is high.
 Installation and reconfiguring is a typical task.
 Complex to understand.

23.  When a network topology is formed by integrating two or more
topologies together, this results in a hybrid topology. Hybrid topologies
can be configured as per the company’s requirement. When configured
properly, hybrid topologies can provide the best of all the network
topologies.
Hybrid topology

24. Just to understand

25. Additional info
 A tree network topology is one of the most common examples of a
hybrid topology.
 It is also referred as a star-bus network topology in which star networks
are interconnected with one another using a bus network.
 In a tree topology, nodes are connected with one another in a hierarchical
manner and are therefore also known as hierarchal topology.

26. Advantages
 Flexibility.
 Scalable; Easy to add or remove nodes.
 Suitable for large networks.
 Easy to manage.

27. Disadvantages
 Costly.
 Complex to design and maintain.