Physical Topologies

Physical Topologies:
A topology is basically a map of a network. The physical topology of a network describes the layout of the cables and workstations and the location of all network components. Often, physical
topologies are compared to logical topologies, which define how the information or data flows within the network. The topologies are usually similar. It is important to note, however, that a network can have one type of physical topology and a completely different logical topology. This was discussed earlier in the sidebar “Physical vs. Logical Concepts.” 

   The cables or connections in a physical topology are often referred to as network media (or physical media). Choosing how computers will be connected in a company’s network is critical.
A wrong decision in the physical topology makes the media difficult to correct because it is costly and disruptive to change an entire installation once it is in place. The typical organization changes the physical layout and physical media of a network only once about every 10 years, so it is important to choose a configuration that you can live with and that allows for growth.

      In the next section, we’ll look at physical media. In the following sections, we’ll look at the  five most common topologies:

• Bus
• Star
• Ring
• Mesh