pctechguide.com

Ethernet

Ethernet was developed in the mid 1970s by the Xerox Corporation, and in 1979 Digital Equipment Corporation DEC) and Intel joined forces with Xerox to standardize the system. The first specification by the three companies called the Ethernet Blue Book was released in 1980, it was also known as the DIX standard after the collaborators’ initials. It was a 10 Mbit/s system that used a large coaxial cable backbone cable running throughout a building, with smaller coaxial cables tapped off at 2.5m intervals to connect to workstations. The large coaxial cable – usually yellow in colour – became known as Thick Ethernet or 10Base5. The key to this nomenclature is as follows: the 10 refers to the speed (10 Mbit/s), the Base refers to the fact that it is a baseband system and the 5 is short for the system’s maximum cable length run of 500m.

The Institute of Electrical and Electronic Engineers (IEEE) released the official Ethernet standard in 1983 called the IEEE 802.3 after the name of the working group responsible for its development, and in 1985 version 2 (IEEE 802.3a) was released. This second version is commonly known as Thin Ethernet or 10Base2, in this case the maximum length is 185m even though the 2 suggest that it should be 200m.

In the years since, Ethernet has proven to be an enduring technology, in no small part due to its tremendous flexibility and relative simplicity to implement and understand. It has proven to have such staying power and popularity that companies like Megapath are improving upon the current technology. Indeed, it has become so popular that a specification for LAN connection or network card generally implies Ethernet without explicitly saying so. The reason for its success is that Ethernet strikes a good balance between speed, cost and ease of installation. In particular, the ability of the 10BaseT version to support operation at 10 Mbit/s over unshielded twisted pair (UTP) telephone wiring made it an ideal choice for many Small Office/Home Office (SOHO) environments.

Ethernet’s Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Media Access Control (MAC) protocol defines the rules of access for the shared network. The protocol name itself implies how the traffic control process actually works. Devices attached to the network first check, or sense, the carrier (wire) before transmitting. If the network is in use, the device waits before transmitting. Multiple access refers to the fact that many devices share the same network medium. If, by chance, two devices attempt to transmit at exactly the same time and a collision occurs, collision detection mechanisms direct both devices to wait a random interval and then retransmit.

With Switched Ethernet, each sender and receiver pair have the full bandwidth. Implementation is usually in either an interface card or in circuitry on a primary circuit board. Ethernet cabling conventions specify the use of a transceiver to attach a cable to the physical network medium. The transceiver performs many of the physical-layer functions, including collision detection. The transceiver cable connects end stations to a transceiver.

Ethernet’s popularity grew throughout the 1990s until the technology was all but ubiquitous. By the end of 1997 it was estimated that more than 85% of all installed network connections were Ethernet and the following year the technology reportedly accounted for 86% of network equipment shipments. Several factors have contributed to Ethernet’s success, not least its scalability. This characteristic was established in the mid-1990s when Fast Ethernet offered a 10-fold improvement over the original standard and reinforced a few years later by the emergence of Gigabit Ethernet, which increased performance a further 10-fold to support data transfer rates of 1000 Mbit/s.

Guides

Recent Posts