What is network topology?

When you think of a network, you may not fully realise the array of configurations available to administrators, each of which serves different purposes and yield different results so it's important to select the right one for your business and its goals.

A differentiation between network topologies, a method of laying out a network, can affect the speeds the network provides to employees and the range it covers across the office, so getting it right and having a full understanding of the topologies is hugely important.

Network topology can refer to both physical and logical network configurations. Physical topologies refer to the geographic layout of 'nodes' which consist of routers, switches, cables and software features for switches or routers. Logical topologies refer more to how signals act on the network, changing the way data flows through it.

Bus topology

In a bus topology, all the nodes on the network connect to a single backbone cable, which services all the devices. This is one of the easiest network types to set up, but it has a few major drawbacks in that adding too many devices can seriously impact the network's speed as the backbone becomes more congested. This kind of network is also incredibly fragile, as a failure at any point in the network will take the entire network offline.

Star topology

The network topology that most users will probably be familiar with is the star topology, in which all of the nodes connect to a single central point, such as a router. A plus side to star is that it's easy to set up through its simple 1:1 ratio of devices to cables and each device only requires one port but the cost of installation is high.

Tree topology

Tree topologies are an evolution of the star model, and involve multiple star networks linked together by a central bus. Tree networks are generally regarded as the most scalable topology, as it's easy to expand through adding additional star networks.

Ring topology

Essentially a bus network that loops around and connects to itself, ring topologies are peer-to-peer networks in which each node is connected to its immediate neighbour on either side, with data travelling around the ring in one direction until it reaches the correct node. As with bus networks, the failure of a single node will cause an outage across the entire network, and poor bandwidth on one inter-node link will bottleneck the whole system. On the other hand, this form of network doesn't require a server to administrate it, and performs better under load than bus networks.

Mesh topology

One of the most advanced forms of network is mesh topology, which is when there is more than one connection between nodes. This can be a full mesh' topology, in which every node is linked to every other node, or a partial mesh, in which only some nodes utilise multiple connections. A mesh topology benefits from being robust and easily diagnosable when things go wrong, but the installation can be difficult and the cost of maintaining it can be high.