This document discusses the basic concepts of networking, not the entire scope. Topology is the arrangement of the various parts of the network. The types describe how information is handled across the system. Star topologies connect each computer to a central hub so data can travel quickly between computers. This formation is the easiest to manage and upgrade but will fail if the central hub is down.
Rings are more stable because data can only flow in one direction along a common path.
However, travel is slower and prone to possible node bottlenecks. Lastly, bus topologies are laid out with each computer on a serial line with a terminator at each end. Protocol is in fact the language communicated between devices. As in society, two people talking in two different langauges will be very confused and the dialog will be near impossible. With the first, all computers may send and receive data, but when a collision occurs, one of the two computers will pause for a random amount of time and try processing again.