Fully switched network
An Ethernet network is usually composed of routers, hubs, and workstations. These workstations share the Ethernet connection with each other. In a fully switched network all of the hubs that would usually reside on an Ethernet network are replaced with one or more switches. These switches allow for a dedicated connection to each workstation. A switch allows for many conversations to occur simultaneously. Before switches existed data could only be transmitted in one direction at a time, this was called half-duplex. By using a switch the network is able to maintain full-duplex Ethernet. This means that data can now be transmitted in both directions at the same time. A good analogy for this would be traveling on a highway with traffic flowing in both directions.
The core function of a switch is to allow each workstation to communicate only with the switch instead of with each other. This in turn means that data can be sent from workstation to switch and from switch to workstation simultaneously. The above describes a fully switched network.
The core purpose of a switch is to decongest network flow to the workstations so that the connections can transmit more effectively; receiving transmissions that were only specific to their network address. With the network decongested and transmitting data in both directions simultaneously this can in fact double network speed and capacity when two workstations are trading information. For example if your network speed is 5 Mbit/s, than each workstation is able to simultaneously transfer data at 5 Mbit/s.
Fully switched networks employ either twisted-pair or fiber-optic cabling, both of which use separate conductors for sending and receiving data. In this type of environment, Ethernet nodes can forego the collision detection process and transmit at will, since they are the only potential devices that can access the medium. Simply stated a fully switched network is a collision-free environment.
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