The key factor in determining the performance of a network is its topology. By topology, it means how a network is organized. Each network consists of different nodes and these nodes are connected to each other with links. The arrangement of these links in different ways results in different kinds of network topologies. These links can be defined both physically and logically.
There are a lot of ways in which a network can be organized and each type of topology has its own pros and cons. If you are responsible for choosing a topology for your network there are a few things you should consider before making a decision. Number of nodes i.e. number of machines in your network, budget, and the aim of the network are the most important factors in deciding which network topology should be selected.
For effective management of network topology we have to do several tasks such as visual mapping, monitoring the performance of the system, and configuration management. The key here is to understand what the requirement of your business is and then choose a network topology that meets these requirements.
In this article we will discuss in-detail different types of computer network topologies, their advantages and drawbacks, and how to pick which network topology is the best for your business.
What Is Computer Network Topology?
A network consists of various components such as different devices which are called as nodes, and links or connections. These connections can be arranged logically or physically. In order to have a better understanding of computer network topology consider that if your city is a computer network then the roadmap of your city will be the topology. Similarly, when setting up a roadmap for a city a lot of factors are taken into consideration such as how much traffic should a avenue be able to handle at peak hours, will a certain boulevard facilitate the flow of traffic between two parts of the city, will there be a need of an alternative route to a certain part of town to prevent traffic jam, how big is the city and how much traffic does it hold, what is the budget set by the government for setting up a roadmap for the city etc. . Similarly, in the case of selecting a computer network topology we also have to consider factors such as how much traffic will be on this network, size of the network, goal of the network i.e. it should be able to handle more traffic, transfer data quickly ,secure etc. budget of the company etc. Each computer network topology has its own pros and cons and depending on these pros and cons we pick what sort of network topology we need for our business.
There are two types of connections in a computer network system. These types are as follows:
- Physical Network Topology:
It can be explained as the type of connection that is tangible. These are the physical connections in a network such as wires, routers, switches, cables, etc. It is the physical layout of nodes and the connection between the nodes of the network.
- Logical Network Topology:
It can be explained as the non-tangible part of the connection or the software configuration of the network. It shows how data flows inside of a network. An example of such configuration is VLAN’s (Virtual LAN’s). Logical topologies of two systems can be the same even if they have different physical topology.
Types of Computer Network Topologies
There are various types of computer network topologies but the most common type of computer topologies are as shown
Point-to-Point computer network topology consists of only two nodes which can be computers, servers, switches, routers, etc. These two nodes are connected together with the help of a single link which is usually a cable. This is the most simple and basic form of computer network topology. If the connection between the two nodes is a logical network connection then there can be a number of intermediate devices in between them but the computers at both nodes will not know about them as they consider each other connected directly.
It is a type of computer network topology in which all the nodes of the network are connected by a single link. It is also known as backbone topology or in some cases as line topology.
The data can only be communicated in one direction at a time in Bus topology. As soon as data reaches the last node of the computer network the data is removed from the link by terminator.
- Simple layout makes it cost effective and a good choice for small computer networks.
- More nodes can be easily added to the computer network.
- They only have one link which makes it vulnerable. If the link breaks than the whole network will be down.
- Not good for large scale businesses as they do not offer larger bandwidth and the seed of transmission will decrease with the addition of nodes.
- Data can only be sent in one direction.
It is a type of computer network topology in which all the nodes of the computer network are linked together such that they form a circle or a ring structure. The data in this type of topology can only flow in one direction at a time. Every node is connected to only two other adjacent nodes.
- Data loss or the loss of packets rarely happen in this type of topology as repeaters can be implemented at each node.
- At a time only one node can send data which removes the chances of packet collision and makes its efficient for transmitting data.
- Cost effective and easier to install.
- Troubleshooting is easy
- As the flow of data is unidirectional, if any nodes go offline the whole computer network will be down.
- If the link between any nodes breaks the whole network will be offline.
- This topology is not effective for larger businesses as the data transmission speed decreases with the addition of nodes.
- In order to add a new node it is required to take the whole network offline.
Dual Ring Topology
It is a type of computer network topology that is similar to the ring topology but the only difference is that the data can flow in both directions at a time. The flow of the data is bi-directional in this topology. There are two rings namely primary ring and secondary ring.
- Very efficient topology as each node has two connectors on each side
- Secure as in if one link fails the other is still working.
It is a type of computer network topology in which every node of the network is connected to a central device. Usually these central devices are Hubs, switches, and routers. They mostly perform the tasks of routing, managing data transmission, and preventing data loss. This central device acts as middleware between all the nodes of the system. Whenever a node wants to provide or is requesting for service it has to communicate with the central device first. Each node has a point-to-point link with the central device. Depending upon the type of central device the messages are either broadcast or unicast. Hubs broadcast messages whereas, switch unicasts messages and maintain a table, and routers act as a gateway between two different networks and connect them. If the Hub is the central device then unnecessary traffic in the network increases because of the broadcasting of messages. The central device acts as a server whereas all the nodes act as clients.
- Easy to use.
- Centralized control
- If a link between any node and central device breaks it would not affect the working of other nodes
- Easily be upgraded and configured.
- If the central devices gets faulty or breaks down then the whole network goes offline
- The total number of nodes in the system depends on the port capacity of central device i.e. Hubs have around 4 to 12 ports whereas switches have 24 to 48 ports.
It is a type of computer network topology which is most commonly used. This topology is also known as hierarchical topology. This type of topology consists of properties of star topology as well as bus topology. In this type of topology the network is divided into multiple layers. The lowest level is known as the Access level or Access layer of the network. This layer consists of all the computers that are present in the computer network. The middle layer of the network topology is known as the Distribution layer.
The middle layer or distribution layer acts as a link between the upper layer and lower layer. The distribution layer acts as a mediator and helps communication between the upper and lower layers. The highest layer in the network is known as the core layer and is the central point of the computer network. As a whole this topology is known as Tree topology because it is organized as a Tree i.e. the core layer acts as the root of the tree, the distribution layer and access layer act as the barks and branches of the tree. The link between the distribution layer and access layer is similar to the start topology. If the root goes offline then the whole system goes offline. This property of tree topology is similar to the property of Bus topology.
- Addition of a new node in the network is easy. The network is easily scalable.
- Troubleshooting is easy as each node in the network can be accessed and assessed individually.
- If one hierarchical network fails the other networks are not affected by it and the system stays online.
- There is no data or very less data loss.
- Root is the most important part of the network and if it goes down or if its health is affected then the overall network goes down.
- Adding a new node is expensive. It requires a lot of cabling.
It is a type of computer network topology in which the nodes of the computer network are interconnected. These nodes are connected in a point-to-point manner. Two different types of data transmission methods are used in mesh topology. The two types of data transmission methods are:
In this type of transmission method the nodes of the computer act intelligently and use logic to figure out what is the shortest from the source of the data to the source of the data. After determining the shortest and quickest path the data is transmitted on that path.
In this type of transmission method the data is transmitted to all the nodes of the network without acting intelligently or using any logic.
There are two types of Mesh topologies which are as follows:
1. Full Mesh:
In this type of mesh topology all the nodes of the network are linked with each other. It is the most reliable computer network topology when compared to all the other computer network topologies. If a new host or node is added into the network having full mesh topology than the number of links that it will have can be calculated using this formula:
Number of links = Number of nodes*(Number of nodes-1)/2
2. Partial Mesh:
In this type of mesh topology not all the nodes of the computer network are interconnected or linked with each other. Some nodes may be connected and some aren’t depending upon the purpose the network is serving and the goals of the network. In this type of mesh topology we provide reliability to some of the nodes and not all depending upon the requirements of the users.
- They offer stability to the network
- They offer reliability to the network i.e. if one nodes is not working it will not take the whole system or network offline
- Each node has a dedicated channel which prevents congestion of traffic and facilitates direct communication with the nodes
- Data is transmitted at great transmission rates
- Maintains privacy of the network
- It is very cost inefficient as each node requires a direct connection with all the other nodes.
- Setting up this topology requires a lot of cabling resources and is very labor intensive
- Installing a new node is very troublesome as setting it up requires a lot of new links and maintaining the existing nodes and links is also very time consuming
- Large working spaces are needed for business that implement mesh topology.
It is a type of computer network topology that is constructed by combining different computer network topologies. Hybrid topologies are constructed keeping in mind the drawback and advantages of all the other topologies. Then they are arranged in such a manner that the drawbacks of one topology is covered by the other topology. In simple words we choose topologies in such a manner that they all take care of each other’s drawbacks and disadvantages. Some of the examples of hybrid topologies are:
In this kind of hybrid topology Bus topology and Star topology are used. A bus is considered as the backbone of the computer network and it connects multiple stars.
In this type of hybrid topology Star topology and Ring topology are used. A single hub connects all the other ring networks. The advantage of Ring topology is that it offers reliability of data whereas star topology offers good tolerance. Combining them results in a network that has good tolerance and data reliability
- Troubleshooting in such types of networks is easy as we can isolate the faulty part of the network after identifying it. The faulty part can be corrected without affecting the rest of the network.
- The networks are easily scalable. The size of the network can be increased without disrupting the service of the network.
- These networks are highly flexible. They can be constructed according to the requirement of the business for example if a node has high traffic flow then it can be given special care so that the traffic is handled without any data loss.
- These networks are very effective as they are designed in such a way that drawbacks of different topologies are balanced out and their advantages are enhanced.
- Designing hybrid networks requires a lot of time and effort as it is not easy to combine different computer network topologies and make them work in a way that benefits the business and meets their goals. The configuration process needs to be done with a lot of precision and care. All in all it is not as easy as it looks.
- These computer networks are cost inefficient as the central devices needed for these networks should be intelligent enough and use effective logics to handle the data flow between different networks having different architectures and functions.
How to decide which topology is best for your business?
There are certain factors one should consider while choosing which topology is best for their business. Following are the most important factors ones should consider while choosing a computer network topology for their business:
- Aim of business
- Cost efficient
- Aim of business:
Finding out the computer network topology that suits and meets the needs of the business is the most important factor in determining which network topology should be adopted. Each business has its own requirements and needs for example some businesses require a high data transmission rate whereas some businesses require to handle greater amounts of data in real time.
Every business has the potential to grow and expand. So scalability of the computer network topology used is an important factor. If the business owners are able to predict the growth of the business then it will make it easier to pick a certain computer topology. Each topology has its own scalability potential for example Star topology makes it easier to add or remove a node from the network as each node has an individual link with the central device whereas in the case of Ring topology addition or removal of a node is very troublesome as the whole network goes offline for these tasks to be executed.
- Cost efficient:
Cost is always an important factor in general. Every business wants to save money, reduce cost, and increase its revenues. In case of computer network topologies the complexity of the network is directly proportional to the cost of setting up the network topology. While choosing a computer network topology we have to not only consider the cost of setting up the network but also consider the cost of maintenance of the network and the cost of upgrading the network. There should be a balance between the costs of installation of the network, the maintenance of the network, the operation of the network, and the performance level of the network. For example Mesh topology is probably the most cost inefficient topology as it requires a lot of links whereas in the case of ring topology and star topology the costs of the network is minimal.
Security of the data is a very important part of any business’s policy. Safety and confidentiality of the data is very important and a company’s reputation is at stake when it comes to the safety of data. The most secure network topology is Mesh topology as it provides dedicated connection to each node and the probability of losing data packets is minimal and the security offered is the best.
Having discussed all the various types of topologies in detail it’s safe to say that we know what a computer network topology is and why there is a need for these topologies. Computer network topologies are important for any business that requires networking. When it comes to choosing which topology is best there is no definite answer. The best computer network topology is the one that suits the business goals. Each computer network topology has its own advantages and disadvantages.