Switches

Switches, routers and bridges, and distribute the traffic load or application content (eg a Web URL identifier) devices is a marketing term. Switches one or more (that is, from beginning to end) physical, data link, network or transport layers, including the OSI model, can operate. Multiple layers of activity at the same time that a device called a multi-layer switch.
Bad “key” is defined in terms that try to understand the first network Overemphasizing often leads to confusion. Many experienced network designers and operators, equipment not related to only one protocol level, each with a logic that are covered by OSI recommended starting. Multilayer device selection by the selection of the applications in question could lead to an advanced topic, but it is not only a multi-layer switching, real-world design concept.
Routers

router
Router, a network device transmits packets between network protocols and routing tables in the header for each packet of information to determine the best use for the next step. OSI network layer model and TCP / IP, Routers Internet at work.