Invented in the 1980's by Bob Metcalfe - Ethernet revolutionazed bandwidth and connectivity in Local Area Networks (LANs). That was then. This is now.
Today Ethernet is used to provide services around the world and is used not only in the LAN, but the WAN as well. We can no longer simply call Ethernet a LAN protocol. As the protocol has developed, so have the features and functions. Learning Ethernet switching and learning the fundamentals of how Ethernets operate is crucial in todays networks for anyone in the networking field.