• Physical topology – Refers to the layout of the devices and media.
• Logical topology – Refers to the paths that signals travel from one point on the network to another. That is, the way in which data accesses media and transmits packets across it.

These two terminologies can be a little confusing, partly because the word "logical" in this instance has nothing to do with the way the network appears to be functioning. The physical and logical topologies of a network can be the same. For instance, in a network physically shaped as a linear bus, the data travels in a straight line from one computer to the next. Hence, it has both a bus physical topology and a bus logical topology.

A network can also have physical and logical topologies that are quite different. For example, a physical topology in the shape of a star, where cable segments can connect all computers to a central hub, can in fact have a logical ring topology. Remember that in a ring, the data travels from one computer to the next. That is because inside the hub, the wiring connections are such that the signal actually travels around in a circle from one port to the next, creating a logical ring. The way data travels in a network cannot always be predicted by simply observing its physical layout.

As for Ethernet and Token Ring, Token Ring uses a logical ring topology in either a physical ring or physical star. Ethernet uses a logical bus topology in either a physical bus or physical star.

All of the topologies discussed above can be both physical and logical, except that no logical star topology exists.