Ethernet - Most widely implemented networking standard

Introduction

Developed by Xerox Corporation in cooperation with DEC and Intel in the late 1970s, Ethernet, is a local area network, using a bus topology, that provides reliable high-speed communications in a limited geographic area. Originally transmission was over thick coaxial cable, but, media today include fiber, twisted-pair (copper), and several coaxial cable types.

There is more than one type of Ethernet. The most commonly installed Ethernet systems are called 10BASE-T and provide transmission speeds up to 10 Mbps; a newer standard called Fast Ethernet uses higher-quality cabling that will carry 100 megabits per second without degrading the signal. The latest but not as widely implemented, is a version that sends data at 1 gigabit per second. And the 10-gbps version is on the horizon. These super fast connections are often used to create large networks, as they prevent data bottlenecks, or gridlock.

Ethernet can be used with almost any kind of computer. It allow several computers to transfer data over a communications cable. It is used to connect computers, printers, workstations, and other devices within the same building.

How Does Ethernet Works?

With a bus topology, all devices or hosts on the network use the same shared communication line. Each of the device possesses an Ethernet address. Sending devices use Ethernet addresses to specify the intended recipient of messages.

Data sent over the Ethernet exists in the forms of frames and is automatically broadcast to all devices on the network. Devices wanting to transmit on the Ethernet first perform a preliminary check to determine whether the medium is available or whether a transmission is currently in progress. If the Ethernet is available, the sending device transmits onto the wire. It's possible, however, that two devices will perform this test at approximately the same time and both transmit simultaneously.

By design, as a performance tradeoff, the Ethernet standard does not prevent multiple simultaneous transmission. These so-called 'collisions', when they occur, cause both transmissions to fail and require both sending devices to re-transmit. Ethernet uses a algorithm based on random delay times to determine the proper waiting period between re-transmissions. The network adapter also implements this algorithm.

Why use Ethernet

For more than 20 years, Ethernet has been in use in local area networks (LAN) and has since become the most most popular and widely-used networking protocol. Primarily attributable to its low implementation cost and reliability, its penetration has grown to the point that nearly all traffic on the Internet traverses an Ethernet connection. Standard Ethernet is also tolerant of faults like overlong cable segments and loose connections.