A physical network topology diagram shows the structure of how devices are connected physically inside a network. A logical network topology diagram shows the logical method of communication used by the devices inside the network for network communication. Physical topology specifies the layout how devices are physically connected in the network. Instead, logical topology specifies the manner in which data travels between devices in the network.
Physical topology shows how a network looks physically, but logical topology shows the fashion in which data is circulated inside the network.
Examples of Logical Topology
Logical Bus topology – In Logical Bus topology, the data travels in a linear fashion in the network similar to bus topology. When devices are connected inside a network using a hub, the real physical network looks similar to star topology. When connected using a hub, the network become shared media and data travels linearly (as in bus topology) inside the shared medium.
Logical Ring topology – In Logical Ring topology, the data travels in a circular fashion in the network similar to ring topology. But the physical appearance of logical ring based networks (Example : Token Ring networks), is similar star topology. But the Multistation Access Unit (MAU) transmits the data in a circular fashion inside the network.