INTRODUCTION TO NETWORK TOPOLOGY
A network topology is defined as a well-defined arrangement of network devices in which every device is connected with each other. The network topology may define both logical and physical aspect of the network. However, both the physical and logical network topologies are different in the same network. It is a topological structure of network which may be depicted logically and physically. It is basically an application of graph theory where the communicating device is modelled as network nodes and the connection between all the devices is modelled as links between nodes.
The distance between two nodes, transmission rate, physical interconnections and signal types differ between two networks and the physical topology of network concern with the OSI model (Open system Interconnection). In LAN (Local Area Network), one or more physical links devices are linked together. Graphically mapping of these links results into a geometric shape which is used for describing the physical topology of the network. In the network architecture, there are a wide variety of physical topologies used including Bus, Mesh, Ring, Star (Meena & Manikandan, 2017).
Types of Topology
There are seven basic types of topologies which are mentioned below-
1.Point-to-Point network topology
In this topology, two nodes are connected to each other. One node can send and receive data from another node. This topology is a basic model of conventional telephony and therefore, the value of a permanent point-to-point network is the value of guaranteed as well as an on-demand point-to-point connection is directly proportional to the number of potential pairs of subscribers.
In this topology, all the devices of the network share single communication link. All the network nodes are connected with a single node and for communication, this topology uses CSMA/CD technology. In this network topology, when one node of the network gets failed, it does not affect the working of other nodes of the network, but if the main link of the network gets failed, it affects the working of the overall network. In this, both the ends of the shared channel have line terminator and data is sent only in one direction. When the data is reached to the extreme end, the terminator removes the data from the line.
In this topology, all the nodes are connected with a central hub using the point-to-point connection. Hub devices can be any of the following such as:
- At layer-1 devices such as Repeater or Hub
- At layer-2 devices such as Switch or Bridge
- At layer-3 devices such as Router or Gateway
As in the Bus topology, hub acts a single point of failure and if the hub gets failed, connectivity of the all the nodes connected with the Hub breaks.
In this network topology, every machine connects exactly with two other nodes of the network which create a circular network architecture. In this, when one node sends data to another node, the data travels through all the nodes between the source node to the destination node. The last node of the network is connected with the first node of the network in this topology.
It is also known as Hierarchical topology in which most network topologies are connected in ‘Tree-like structure.’ This topology imitates as extended start topology and inherits the various properties of the bus topology. It divides the network into three layers. In the lowermost layer access layer nodes are connected, in the middle layer known as distribution layer switches and routers are connected and in the highest layer which is core layer of the network central network, devices are connected and it is also known as the root node of the network.
In this topology, one node is connected to one or more multiple nodes. In this topology, node is connected with a point-point connection in which every node is connected with each other. If one node of the network gets failed, it will not affect the working of overall network architecture. Mesh topology is of two types Full Mesh topology and Partial-Mesh Topology.
In this topology, one or more topology is used in a single network which is known as hybrid network topology. This topology inherits all pros and cons of the other topologies.
Meena, S., & Manikandan, J. (2017). Study and evaluation of different topologies in wireless sensor network. 2017 International Conference On Wireless Communications, Signal Processing And Networking (Wispnet). Retrieved from https://ieeexplore.ieee.org/document/8299729