Chapter 8 - Ethernet, Ethernet, and More Ethernet

Abstract

This chapter focuses on Ethernet networks. Ethernet is a local area network protocol (LAN) developed jointly by Xerox, Intel, and Digital Equipment Corporation (DEC) at the Xerox Palo Alto Research Center (PARC) in the mid-1970s. It was designed as a technology that would allow for the interconnection of office devices. Although, the concept of Ethernet was originally developed at PARC, Ethernet's genesis is with the University of Hawaii in the late 1960s to early 1970s. A network called ALOHA was developed, which was used to connect the main campus site in Oahu to seven other campuses on four of the Hawaiian Islands. Using a technique called contention, it was demonstrated that multiple nodes on a network could use the same channel for communications and they could send data whenever they had data to send. The primary difference between the ALOHA network and Ethernet is that ALOHA permitted any node to transmit data at any time, made no provision to allow a node to detect if another node was sending data, and there was no procedure for dealing with collisions, which occur when two or more nodes attempt to transmit data simultaneously. Without a mechanism for dealing with the eventuality of simultaneous transmissions, ALOHA required many retransmissions. Ethernet, on the other hand, was designed with both carrier sense capability (CSMA) and collision detection (CD). The name Ethernet was derived from the old electromagnetic theoretical substance called luminiferous ether, which was formerly believed to be the invisible universal element that bound together the entire universe and all its associated parts. Thus, “ether” net is a network that connects all components attached to the “net.”