Routers
Routers are layer three devices found in the network layer of the OSI model, and Routers use logical addressing of information to direct data among two or more networks. A router helps in finding the best path for traffic from one network to another. A switch is a layer two device found in the data link layer of the OSI model. The data link layer contains protocols programmed into firmware of a computer and networking devices. Fault tolerance in ensures availability of a despite the occurrence of hardware or software malfunction, several data paths are created that enable data to move from one point to another. The extra data paths ensure availability when one component breaks some of the paths. Redundancy is an implementation in which additional components are installed ready to store, process and transport data; this installed component is intended to eliminate positions of failure and ensures availability when a working component fails. Redundant links are also used between components to create a seamless combination of more network interface which act like one logical interface; this reduces chances of bottlenecks in a network.