The Ethernet Essay

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Bob Metcalfe of the Xerox Corporation developed the first experimental Ethernet system in late 1972. The goal of the Ethernet was to interconnect the Xerox Alto Aloha Network. The experimental Ethernet was used to link Altos workstations, servers, and laser printers. Data transmission of the Ethernet was 2.94 Mbps. In 1973, Metcalfe changed the name to "Ethernet," to make it clear that the system could support any computer, and not just Altos, and to point out that his new network mechanisms had evolved well beyond the Aloha system. He chose to base the name on the word "ether" as a way of describing an essential feature of the system. The physical medium (cable) carries bits to all stations, much the same way that…show more content…
The IEEE controls the assignment of these addresses by administering a portion of the address field. The IEEE does this by providing 24-bit identifiers called "Organizationally Unique Identifiers" (OUIs). The organization, in turn, creates 48-bit addresses using the assigned OUI as the first 24 bits of the address. A unique 48-bit address is commonly pre-assigned to each Ethernet network interface card when it is manufactured. As each Ethernet frame is sent onto the shared signal channel, all Ethernet workstations look at the first 48-bit field of the frame, which contains the destination address. The workstations compare the destination address of the frame with their own address. The Ethernet workstation with the same address, as the destination address in the frame will read in the entire frame and deliver it to the networking software running on that computer. All other network workstations will stop reading the frame when they discover that the destination address does not match their own address. After each frame transmission, all workstations on the network must contend equally for the next frame transmission opportunity. This ensures that access to the network cable is fair, and that no single workstation can lock out the other workstations. Access to the shared cable is determined by the medium access control (MAC) mechanism embedded in the Ethernet network interface card located in each
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