In order to understand the explanation of protocols and ports, it is necessary for you to
become familiar with the icons that represent the most common devices that are seen in the
basic schemes. These are:
With these devices, local area networks (or LANs) can be created. In a LAN, computers can
share resources, such as hard drives, printers and internet connections, and an administrator
can control how these resources are shared. When a LAN is being designed, it is possible to
choose any of the following physical topologies:
- In a bus topology, all the computers are connected to a single means of transmission, and each computer can communicate directly with any of the others.
- In the ring configuration, each computer is connected to the following one, and the last one to the first, and each computer can only communicate directly with the two adjacent computers
- In the star topology, none of the computers are directly connected with others. Instead they are connected through a central point and the device at that central point is responsible for relaying information from computer to computer.
- If several central points are connected to each other, an extended star topology is obtained.
- In a star or extended star topology, all the central points are peers, that is, each exchanges information on an equal basis.
However, if you connect two star or extended star networks together using a central point which controls or limits the exchange of information between the two networks, then you have created a single, hierarchical network topology.