Unit 5

Lesson 2 - Ethernet

   Introduction

Ethernet, originally developed in the 1970s by Xerox Corporation in conjunction with Intel and DEC, is now the most widely implemented LAN technology. More than 75 percent of all LANs are Ethernet LANs. This lesson introduces the basics of Ethernet technology and describes the most common Ethernet configurations.

Ethernet is popular because it is fast, inexpensive, and reasonably simple to implement. Ethernet was designed to minimize wiring by connecting computers to a common coaxial bus cable. The original version of Ethernet operated at a burst rate of 10 Mbps. Today's versions use twisted pair cable in a star topology, and can run at throughputs of 10 Mbps, 100 Mbps, or 1 gigabit per second (Gbps), depending on the type of network interface cards (NICs) and cabling used.

Standard Ethernet equipment (NICs, hubs, and cabling) is inexpensive and widely available from many vendors. Most Ethernet LANs use easily installed twisted pair cabling to connect computers and peripherals to hubs.

   Objectives

At the end of this lesson you will be able to:

1.

Describe a collision

2.

Explain how Ethernet controls each node's access to the physical medium

3.

Describe common Ethernet configurations

Key Point
Any Ethernet node may attempt to transmit when the medium is idle.


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