What is a network topology?

A network topology describes the arrangement of devices in a computer network and how they connect to each other.

Star network topology

In a star topology, every device connects directly to a central device, such as a switch or server, which manages all communications.

Advantages of star networks

• Fault isolation - If one device fails, it only affects that device; the rest of the network continues working normally.
• Ease of expansion - Adding new devices is straightforward, as you simply connect them to the central switch without disrupting the existing setup.

Disadvantages of star networks

• Central point vulnerability - If the central switch or server fails, the entire network stops functioning, as all connections rely on it.
• High cabling costs - It requires a lot of individual cables to connect each device to the centre, making installation more expensive compared to simpler layouts.

Bus network topology

A bus topology uses a single main cable, called the backbone, to connect all devices. A key concept here is a data collision, which happens when two or more devices try to send data at the same time along the shared cable. When this occurs, the data interferes with each other and must be resent, potentially slowing down the network.

Advantages of bus networks

• Fault tolerance for devices - If one device fails, it does not impact the others, as they remain connected via the backbone.
• Cost-effective - It uses minimal cabling, just the single backbone and short connections to devices, making it cheaper to set up.

Disadvantages of bus networks

• Collision risks - Frequent data collisions can reduce network speed, especially with many devices sending information simultaneously.
• Backbone dependency - A break in the main cable causes the whole network to fail, as it severs the connection for all devices.

Ring network topology

In a ring topology, devices form a closed loop.

Advantages of ring networks

• High speed and low collisions - Since data moves in one direction only, collisions are rare, allowing for faster and more reliable transmission.

Disadvantages of ring networks

• Network-wide vulnerability - If any device fails or the cable breaks at one point, it disrupts the entire ring, bringing down the whole network.

Mesh network topology

A mesh topology connects devices where each device links directly or indirectly to multiple others.

Advantages of mesh networks

• Redundancy and reliability - Multiple paths allow data to reroute around busy or failed connections, keeping the network operational even if one device goes down.
• Performance optimisation - Data can avoid congested routes, improving overall speed and efficiency.

Disadvantages of mesh networks

• High setup costs - Wired versions require extensive cabling to create all the connections, making them expensive to install and maintain.