76、Network topology can take a bit of time to understand when you＇re all new to this kind of cool stuff, but it＇s very important to fully understand them as they are key elements to understanding and troubleshooting networks and will help you decide what actions to take when you＇re faced with network problems.There are two types of topology:Physical and Logical.The physical topology of network refers to the layout of cables, computers and other peripherals.Try to imagine yourself in a room with a small network, you can see network cables coming out of every computer that is part of the network, then those cables plug into a hub or switch.What you＇re looking at is the physical topology of that network!Logical topology is the method used to pass the information between the computers.In other words, looking at that same room, if you were to try to see how the network works with all the computers you would be looking at the logical part of the network.The way the computers will be talking to each other and the direction of the traffic is controlled by the various protocols ( ) or, if you like, rules.if we use token ring, then the physical topology would have to change to meet the requirements of the way the token ring protocol works ( ).If it＇s all still confusing, consider this:the physical topology describes the layout of the network, just like a map shows the layout of various rads, and the logical topology describes how the data is sent across the network or how the cars are able to travel ( ) at every road on the map.(2)、What is logical structure?