Ethernet was the first commercially available local area network system
and remains, without a doubt, the most popular LAN system today. The wired
version of Ethernet is based primarily on the star-wired bus topology and uses
essentially the CSMA/CD medium access protocol. Because Ethernet is so
popular and has been around the longest, it has evolved into a number of different
forms. To avoid mass mayhem, IEEE created a set of individual standards specifically for Ethernet or CSMA/CD local area networks, all under the category
of 802.3. Let us examine the different 802.3 protocols in a little more
detail. For your reference, the 802.3 standards to be discussed are summarized
in Table 7-1.