A network topology is configuring computer systems or network objects that link to one another. Topologies can specify both the natural and conceptual aspects of a network. In the same network, abstract and real networks may be the same or distinct.
The actual or conceptual organisation of devices, components, and links in a computer network is called “network topology.” It specifies how network components are linked together and with one another.
Types of network topologies:
Bus topology: In a bus topology, all terminals are linked to a shared transmission connection, which is the network’s backbone.
Star topology: A star architecture connects all components to a central hub or switch, which is a focal point of management and contact.
Ring topology: All of the nodes in a ring topology are linked in a circular circle, with each node tied to the next node in the loop.
Mesh topology: In a mesh topology, every node in the network is connected to every other node, so there are many ways for nodes to talk to each other.
Tree topology: A tree topology is an organized arrangement of nodes, with a parent node at the top and child nodes at the bottom.
Hybrid Topology: This topological technology combines all the different topologies discussed above. It is used when the nodes can assume any shape they want.
Bus Topology
In a bus architecture, all terminals are linked to a shared transmission connection that is the network’s backbone. The nodes share the transmission channel, and any device on the network can send data to any other device. If the transmission connection fails, the entire network suffers.
Every computer and network device is linked to a single wire in a bus-architecture network. It operates in both directions. It is a multi-point link with a non-robust topology because the topology breaks if the backbone fails. Ethernet links in bus topology use different MAC (Media Access Control) methods such as TDMA, Pure Aloha, CDMA, Slotted Aloha, etc.
Advantages of this topology:
- When N devices are linked in a bus topology, the amount of wire needed to connect them is one, known as a backbone cable, and N drop lines.
- Most bus-based networks with data rates of up to 10 Gbps use coaxial or twisted pair connections.
- The wire is less expensive than other designs but only used to create tiny networks.
- Bus topology is a well-known system with well-known implementation and repair methods.
Disadvantages with this topology:
- A bus topology is much easier but still requires a lot of wiring.
- If the shared connection breaks, the entire device will collapse.
- When network traffic is high, accidents occur more frequently. Different algorithms, such as Pure Aloha, Slotted Aloha, and CSMA/CD, are used in the MAC layer to prevent this.
- Introducing additional gadgets to a network would cause it to slow down.
- The level of security could be much better.
Star Topology
All components in a star architecture are linked to a central hub, or switch, which serves as a point of management and contact. The seat or switch handles network data; if one component breaks, the remainder of the network is unaffected. The junction or switch, on the other hand, can be a singular point of failure.
A point-to-point link connects all servers in the star architecture to a central device known as the hub device. That is, a point-to-point link occurs between servers and the centre.
Advantages of this topology:
- If N devices are linked in a star configuration, the number of wires needed to connect them is N. As a result, it is simple to set up.
- Because each device needs only one port to link to the centre, the total number of ports needed is N.
- It is tough. If one connection breaks, it will not affect the others.
- It is simple to identify and isolate faults.
- Because the coaxial wire is cheap, the star topology is cost-effective.
Disadvantages with this topology:
- If the Centre on which the entire architecture is based breaks, the system will collapse.
- The service fee is expensive.
- The performance is predicated on a single collector or centre.
Ring Topology
A ring structure connects all the nodes in a closed circle, with each node linked to the next node in the cycle. Data moves around the ring in one way, and each node regenerates and sends the data to the next node. When one component breaks, the entire network suffers.
In a ring architecture, each host computer connects to exactly two other machines, forming a circle network structure. When one host attempts to interact with or deliver a message to a host not close to it, the data passes through all intermediary hosts. The supervisor may only need one more wire to join one more server in the current framework.
Advantages of this topology:
- High-speed data transfer
- In this geometry, the chance of impact is minimal.
- Installing and expanding it is inexpensive.
- It is less expensive than star geometry.
Disadvantages with this topology:
- A single component breakdown can cause the complete network to collapse.
- In this structure, troubleshooting is challenging.
- The inclusion or elimination of nodes between them can disrupt the entire structure.
- Not safe.
Mesh Topology
In a mesh architecture, each node is connected to every other node in the network. This means that there are many ways for nodes to talk to each other. This architecture is reliable and can handle problems because data can be sent through another channel if one break. However, it is more costly and more challenging to implement and operate.
A server is linked to one or more hosts in this structure.
This architecture has point-to-point hosts connected to every other server or hosts that are only point-to-point connected to a few hosts.
Advantages of this topology:
- Transmission between nodes is rapid.
- The problem is readily identified. Data is dependable because it is transmitted between devices via designated routes or connections.
- It offers protection and seclusion.
Disadvantages with this topology:
- Installation and setup are challenging.
- Cables are expensive because mass cabling is needed, which makes them ideal for a limited number of devices.
- The expense of upkeep is high.
Tree Topology
Nodes in a tree layout are organised hierarchically, with a root node at the top and child nodes at the bottom. The base node is linked to one or more nodes, which are then connected to other nodes, resulting in a spreading structure. Although this architecture is flexible and practical, the complete network may suffer if the primary node breaks.
This network architecture splits the network into numerous levels or layers. In LANs, a network is divided into three kinds of network components. The lowest stratum is the access layer, to which machines are connected. The intermediate layer is known as the dissemination layer and serves as a bridge between the top and bottom layers. The topmost layer is known as the core layer, and it serves as the network’s centre point, or the base of the tree, from which all nodes branch.
Advantages of this topology :
- Include connecting more devices to a single central hub and reducing the distance traversed by the signal to reach the machines.
- It enables the network to be separated from and prioritised among various devices.
- We can expand the network by adding additional gadgets.
- In a tree structure, mistake discovery and repair are simple.
Disadvantages with this topology :
- The complete mechanism collapses if the primary hub crashes.
- Because of the wiring, the expense is significant.
- When new gadgets are introduced, reconfiguring them becomes challenging.
Hybrid Topology
A mixed topology combines two or more networks. A network, for example, could have a star topology at the centre and a bus topology linking the components to the core. This architecture is adaptable and can be customised for particular network needs.
A mixed topology is a network framework that is designed with more than one architecture. The benefits and drawbacks of all combining configurations are combined in the composite topology.
The image above depicts an arbitrary mixed structure. The merging topologies can have characteristics of the star, ring, bus, and daisy-chain topologies. Most WANs use dual-ring topology, and the networks that connect to them are primarily star-topology networks. The Internet is the most prominent illustration of an extensive mixed network.
Advantages of this topology :
- This topology is extremely adaptable.
- The network’s capacity can be readily increased by adding new devices.
Disadvantages with this topology :
- The framework of the hybrid network is challenging to build.
- The hubs used in this topology are highly costly.
- Because a diverse network needs a lot of wiring and network devices, the hardware cost is very high.
