Types of Network Topology
Types of Network Topology
Types of Network Topology
The arrangement of a network which comprises of nodes and connecting lines via
sender and receiver is referred as network topology. The various network topologies
are :
a) Mesh Topology :
Figure 1 : Every device is connected with another via dedicated channels. These
channels are known as links.
If suppose, N number of devices are connected with each other in mesh topology, then
total number of ports that is required by each device is N-1. In the Figure 1, there are
5 devices connected to each other, hence total number of ports required is 4.
If suppose, N number of devices are connected with each other in mesh topology, then
total number of dedicated links required to connect them is NC2 i.e. N(N-1)/2. In the
Figure 1, there are 5 devices connected to each other, hence total number of links
required is 5*4/2 = 10.
Advantages of this topology :
It is robust.
Fault is diagnosed easily. Data is reliable because data is transferred among the
devices through dedicated channels or links.
Provides security and privacy.
Problems with this topology :
Installation and configuration is difficult.
Cost of cables are high as bulk wiring is required, hence suitable for less number of
devices.
Cost of maintenance is high.
b) Star Topology :
In star topology, all the devices are connected to a single hub through a cable. This
hub is the central node and all others nodes are connected to the central node. The
hub can be passive in nature i.e. not intelligent hub such as broadcasting devices, at
the same time the hub can be intelligent known as active hubs. Active hubs have
repeaters in them.
c) Bus Topology :
Bus topology is a network type in which every computer and network device is
connected to single cable. It transmits the data from one end to another in single
direction. No bi-directional feature is in bus topology.
Figure 3 : A bus topology with shared backbone cable. The nodes are connected to
the channel via drop lines.
If N devices are connected to each other in bus topology, then the number of
cables required to connect them is 1 which is known as backbone cable and N
drop lines are required.
Cost of the cable is less as compared to other topology, but it is used to built
small networks.
Problems with this topology :
If the common cable fails, then the whole system will crash down.
If the network traffic is heavy, it increases collisions in the network. To avoid
this, various protocols are used in MAC layer known as Pure Aloha, Slotted
Aloha, CSMA/CD etc.
d) Ring Topology :
In this topology, it forms a ring connecting a devices with its exactly two
neighbouring devices.
e) Hybrid Topology :
This topology is a collection of two or more topologies which are described above.
This is a scalable topology which can be expanded easily. It is reliable one but at the
same it is a costly topology.