Ethernet is the most popular and widely deployed network technology in the world. In 1973, while working on a way to link the Xerox “Alto” computer to a printer, Bob Metcalfe designed and tested the first Ethernet network. This first Ethernet network defined the physical cabling required of a connected device and defined the standard communications required on the cable.
As electronics and networking have grown, the Ethernet standard has developed to include the new technologies, but the basic mechanics of operation of every Ethernet network stems from Mr. Metcalfe’s original design at the Xerox Corporation’s Palo Alto Research Center. The original Ethernet design described communication over a single cable shared by all devices on the network.
This allows the network to expand to accommodate new devices without requiring any modification to those devices already on the network.
In the beginning, Ethernet networks were set up in a multidrop network based on Metcalfe’s original “Ether” trunk, where devices “tapped” into the information highway. Ethernet network topologies have since evolved into star networks that include hubs, switches, and routers. A hub is a passive device that passes or buses all the information on the network to every connected device.
An Ethernet switch is a step above a hub; it incorporates the same function of a hub where it passes the data to all connected devices but includes the capability to decode parts of those messages and uses this decoded information to direct the traffic to the appropriate internet protocol (IP) address. Switches also have the ability to avoid message collisions by managing the data via store-and-forward methods that act in a deterministic fashion.
The process is prescribed in the Ethernet Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol.
Finally, routers are similar to switches, except they add the function of routing traffic from a LAN to another LAN, thus creating a Wide Area Network (WAN).