In Networks communication, a topology is a usually representation and description of the arrangement of a communication network, as well as its nodes and connecting lines or medium. There are two types ways of describing network geometry: the physical topology and the logical or signal topology.
The physical topology of a network is the actual arithmetical or geometrical outline of workstations. There are several common physical topologies.
In the bus network topology, every workplace is connected to a main cable or node called the bus. Therefore, in effect, each terminal is directly connected to every other terminal in the network areaIn the star network topology, there is a central main computer or server to which all the workstations are in a straight line connected. Every workstation is not directly connected to every other node through the central computer.

In the ring network topology, the workstations are connected in a closed ring pattern. Neighboring pairs of workstations are straight connected. Other pairs of workstations are not directly connected, the data passing through one or more in-between nodes.
If a Token Ring protocol is used in a star or ring topology, the signal actions or travels in only one direction, passed by a so-called token from point to point or node to node.

The mesh network topology employs either of two schemes, known as full mesh and partial mesh. In the full mesh topology, each workplace is connected straight to each of the others. In the partial mesh topology, some workplaces are connected to all the others, and some are connected only to those other nodes with which they exchange the most data.
The tree network topology uses two or more star networks connected together. The central hub computers of the star topology are connected to a main bus. Thus, a tree network is a bus network of star networks.
Logical or signal topology refers to the 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. For example, some networks are physically laid out in a star configuration, but they function logically as bus or ring networks.

Harshita Bhati