A bridge is used to connect similar networks. A router is an intelligent network connector that sends communications traffic to the appropriate network. A communications network is a collection of terminals, computers, and other equipment that uses communications channels to share data, information, hardware, and software. Networks can be classified as either local area networks or wide area networks. Common applications of local area networks are hardware resource sharing , software resource sharing , and information resource sharing .
Common carriers are public wide area network companies.
A star network topology has a central computer with one or more smaller computers connected to it, forming a star. In a bus network topology, all the devices in the network are connected to and share a single data path. In a ring network topology, the devices on the network are connected in a continuous loop or ring. A protocol is a set of rules and procedures for exchanging information between computers. Protocols define how a link is established, how information is transmitted, and how errors are detected and corrected.