In computer networking, topology refers to the layout of connected devices. In communication networks, a topology is a usually schematic description of the arrangement of a network, including its nodes and connecting lines. There are two ways of defining network geometry: the physical topology and the logical (or signal) topology.

1. Network Topologies
Network Topology- In computer networking, topology refers to the layout of connected devices.
In communication networks, a topology is a usually schematic description of the arrangement of a network,
including its nodes and connecting lines. There are two ways of defining network geometry: the physical topology
and the logical (or signal) topology.
1. Logical Topology- Nature of the paths the signals follow from node to node. In many instances, the logical
topology is the same as the physical topology. But this is not always the case.
2. Physical Topology- Actual geometric layout of workstations.
Network topologies are categorized into the following basic types:
Network Topologies
Types of Physical Topology

2. Network Topologies
a. Point to Point Topology- The simplest topology with a permanent link between two
endpoints. Switched point-to-point topologies are the basic model of conventional
telephony. The value of a permanent point-to-point network is unimpeded
communications between the two endpoints.
Point-to-Point
Advantages:
i. Lower Cost.
ii. Easy to setup.
iii. Good for temporary network setup.
iv. Use for connecting one area to another using a high speed connection.
Disadvantages:
i. Limited growth.
ii. No central location.
iii. Weak Security.
b. Ring Topology- In Ring Topology, all the nodes are connected to each-other in such a way
that they make a closed loop.
A failure in any cable or device breaks the loop and can shut down the entire network.
Every data packet must pass through all the computers between sender and receiver.
Ring Topology

3. Network Topologies
Advantages:
i. Data is quickly transferred without a ‘bottle neck’ (very fast, all data traffic is in
the same direction).
ii. The transmission of data is relatively simple as packets travel in one direction
only.
iii. Adding additional nodes has very little impact on bandwidth.
iv. It prevents network collisions because of the media access method or
architecture required.
Disadvantages:
i. The failure of a single node in the network can cause the entire network to fail.
ii. The movement or changes made to network nodes affect the entire network's
performance.
iii. Data sent from one node to another has to pass through all the intermediate
nodes. This makes the transmission slower in comparison to that in a star
topology. The transmission speed drops with an increase in the number of nodes.
iv. There is heavy dependency on the wire connecting the network nodes in the ring.
c. Star Topology- One of the most common network setups where each of the devices and
computers on a network connect to a central hub. If the central computer fails, the entire
network becomes unusable.
Star Topology

4. Network Topologies
Advantages:
i. Good performance.
ii. Easy to set up and to expand. Any non-centralised failure will have very little
effect on the network, whereas on a ring network it would all fail with one fault.
iii. Adding or removing network nodes is easy, and can be done without affecting the
entire network.
iv. Due to the centralized nature, it is easy to detect faults in the network devices.
v. As the analysis of traffic is easy, the topology poses lesser security risk.
Disadvantages:
i. Expensive to install.
ii. Extra hardware required.
iii. Network operation depends on the functioning of the central hub. Hence, central
hub failure leads to failure of the entire network.
iv. Also, the number of nodes that can be added depends on the capacity of the
central hub.
d. Bus Topology- A bus topology is a type of network setup where each computer and
network devices are connected to a single cable or backbone. A bus network is simple and
reliable. If one node fails to operate, all the rest can still communicate with each other.
Advantages:
i. It is easy to set up, handle, and implement.
ii. It is best-suited for small networks.
iii. Well suited for temporary networks (quick setup).
iv. Initially less expensive than other topologies.
v. Cheap.
Bus Topology

5. Network Topologies
Disadvantages:
i. The cable length is limited. This limits the number of network nodes that can be
connected.
ii. This network topology can perform well only for a limited number of nodes.
When the number of devices connected to the bus increases, the efficiency
decreases.
iii. It is suitable for networks with low traffic. High traffic increases load on the bus
and the network efficiency drops.
iv. It is heavily dependent on the central bus. A fault in the bus leads to network
failure.
v. It is not easy to isolate faults in the network nodes.
vi. Each device on the network "sees" all the data being transmitted, thus posing a
security risk.
vii. Difficult to administer/troubleshoot.
viii. Low security.
ix. Proper termination is required.(loop must be in closed path).
e. Mesh Topology- A network setup where each computer and network device is
interconnected with one another, allowing for most transmissions to be distributed, even
if one of the connections go down.
The flow of information is random and the source to destination path of this information
can take many paths.
Mesh Topology

6. Network Topologies
Advantages:
i. The arrangement of the network nodes is such that it is possible to transmit data
from one node to many other nodes at the same time.
ii. The failure of a single node does not cause the entire network to fail as there are
alternate paths for data transmission.
iii. It can handle heavy traffic, as there are dedicated paths between any two
network nodes.
iv. Point-to-point contact between every pair of nodes makes it easy to identify
faults.
v. Mesh topologies aren’t affected by size or a shortage of users.
Disadvantages:
i. The layout of a mesh topology requires constant supervision and is very expensive
to implement.
ii. A lot of cabling is required.
iii. Owing to its complexity, the administration of a mesh network is difficult.
f. Tree Topology- A tree topology is a type of network topology that includes at least three
specific levels in a topology hierarchy.
Experts may define a tree topology as a combination of star and bus topologies, where
multiple elements are connected through a single lateral connection.
Tree Topology

7. Network Topologies
Advantages:
i. Experts may define a tree topology as a combination of star and bus topologies,
where multiple elements are connected through a single lateral connection.
ii. Expansion of Network is possible and easy.
iii. Error detection and correction is easy.
iv. Each segment is provided with dedicated point-to-point wiring to the central hub.
v. If one segment is damaged, other segments are not affected.
vi. The advantages of centralization that are achieved in a star topology are inherited
by the individual star segments in a tree network.
Disadvantages:
i. Because of its basic structure, tree topology, relies heavily on the main bus cable,
if it breaks whole network is crippled.
ii. Owing to its size and complexity, maintenance is not easy and costs are high. Also,
configuration is difficult in comparison to that in other topologies.
iii. Though it is scalable, the number of nodes that can be added depends on the
capacity of the central bus and on the cable type.