Network topologies in a nutshell

A computer network is a system of interconnected computing resources, such as computers and electronic devices, that facilitates the exchange of data. Typically, a common communication protocol is utilized to transfer information between the network nodes. Computer networks can be classified based on various factors such as their purpose, architecture, and communication methods, resulting in different types of networks.

Here are some examples of networks by area of distribution:

• PAN (Personal Area Network) - a personal network belonging to individual person's workspace.

• LAN (Local Area Network) – a network usually covering a relatively small area or a small group of buildings.

• WAN (Wide Area Network) - is a network that spans large geographic regions (including both LAN and other networks).

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The following are network examples by topology:

• Bus topology

• Ring topology

• Star topology

• Tree topology

• Mesh topology

Computer networks can also be classified based on the type of architecture they employ, such as client-server or peer-to-peer (P2P), as well as the type of connection used, such as wired or wireless. These different architectural and connection types influence the way data is exchanged and processed within the network, leading to varying network performance and capabilities.

Bus topology

A bus topology is a common cable (called a bus or backbone) to which all nodes are connected. Nodes attach to the bus through connectors, and data is transmitted along the cable in both directions. There are terminators at the ends of the bus to prevent signal reflection. This topology is typically used in small networks.

Advantages

• Easy to set up and add more nodes when needed.

Disadvantages

• Troubleshooting can be challenging.

• The addition of more nodes can decrease network performance, making it inappropriate for large local area networks.

• A single issue with the main bus cable can bring the entire network to a halt.

• Security is compromised as all nodes have access to all traffic.

• Higher likelihood of data collisions results in a slower network.

Ring topology

A ring network is a type of topology in which each device is connected to exactly two other devices, creating a circular path for data transmission. In a ring network, each device receives information from one device and transmits it to the next device in the circle. These networks can either be unidirectional, where data flows in a single direction around the ring, or bidirectional, allowing data to flow in both directions.

Advantages of a ring network topology:

• The flow of data in a single direction eliminates network collisions.

• Adding new nodes to the network is painless and has minimal impact on bandwidth.

Disadvantages of a ring network topology:

• A single node failure can disrupt the entire network, causing data transmission to stop.

• Troubleshooting a ring network can be challenging.

• To add more nodes, it is necessary to temporarily shut down the network.

Star topology

A star network is a computer network topology in which all devices are connected to a central node, typically a switch or a hub. The central node acts as a hub, directing all data traffic within the network. In a star network, each device communicates directly with the central node, which has the responsibility of managing and directing the flow of data within the network. The central node typically has a higher processing capacity than other devices in the network to handle the increased network load. This type of network topology can function as a standalone network or as part of a more complex network architecture, such as a tree topology.

Advantages of a star network topology:

• As each node has its own dedicated connection to the central node, its failure doesn’t affect other nodes. For the same reason, it’s easy to troubleshoot.

• New nodes can be easily added to the network by connecting them to the central node.

• Any node failure (except central) doesn’t affect other nodes.

• It has better performance because the data is sent to the intended addressee only.

Disadvantages of a star network topology:

• The central node is a bottleneck - all data passes through it.

• The central node is a single point of failure of network.

Tree topology

The tree topology in a computer network is a combination of star networks. It also referred to as a hierarchical star.

The benefits of this topology include its ease of scalability and control, making it simple to detect and fix any issues. However, a major drawback is that if the parent node experiences a failure, all its child nodes will also fail, resulting in a total breakdown of the subnetwork.

Mesh topology

Mesh topology is a type of computer network configuration that operates on the principle of cells, where nodes are connected to each other and can act as switches for other nodes. While it may be complex to set up, it offers a high degree of fault tolerance. The nodes are typically linked on a one-to-one basis, leading to a large number of connections that provide multiple options for routing traffic. As a result, the failure of a single connection does not affect the overall functioning of the network.

There are two types of mesh topologies – full (each node has direct connection to any other node) and partial (node has a connection to one or more nodes). 

Advantages of a mesh network topology:

• Adding new nodes to the network has minimal impact.

• Data is always delivered because there are many possible routes from the sender node to the addressee node.

• Having multiple connections ensures that no node is isolated and enables each node to simultaneously send and receive data from multiple nodes.

Disadvantages of a mesh network topology:

• The set up might be hard and complicated.

• Due to its complex nature, a lot of maintenance may be required.

• Some part of the network may be redundant if there are better connection routes to the nodes.