While physical topology refers to the way network devices are actually connected to cables and wires, logical topology refers to how the devices, cables and wires appear connected. Learning how devices are connected and how they communicate on a network is important in protecting the whole arrangement.
The difference between physical and logical topology is present and can be demonstrated in a shared Ethernet network that employs hubs instead of switches. With this type of connection, the logical topology looks as if each node is connected into the same bus. However, its physical topology reveals a star-shaped connection. It shows that every node actually connects to a central hub on the network. This example emphasizes the fact that differences in physical and logical topology are only in perspective.
Physical topology can be categorized into five different types: ring, star, bus, hybrid and mesh. In ring topology, devices are attached to one another in a ring shape to have each device connected to another on each of its two sides. While star topology has devices connected to a central hub, bus topology has devices connected to a central cable (bus). On the other hand, groups of networks in a star-shape are connected to a bus in hybrid topology. In mesh topology, each node is connected to every other node to create several redundant interconnections.