Top Ad unit 728 × 90

10: Ethernet - Ethernet history part 2

Ethernet History
Note : if you are a CCNA candidate, you are not supposed to know all these details, as you will not be examined in every part of this lesson. The aim of this lesson is to provide a comprehensive overview of what is known as Ethernet technology. So, it would be better to skip the specifics in case you are not interested.

Any kind of technology has its primitive stages which lack greatness and quality, and Ethernet is no exception. Ethernet technology has passed by many phases to reach the todays’ sophistication. It kept evolving year after year seeking better performance.

Ethernet was first emerged in 1970 when Robert Metcalfe, its inventor, was inspired by the idea of ALOHAnet (It was simple but a pioneering computer networking system developed at the University of Hawaii in the early 1970s as a means of communication), which he has studied as part of his PhD dissertation. Robert Metcalfe named Ethernet after luminiferous ether (it is a hypothetical substance, proposed by the greek philosopher Aristotle, which was thought to exist in space as a completely-passive medium through which electromagnetic waves travel and which allows propagation of light.

In 1973, the very first version of Ethernet was developed at Xerox Corporation by Robert Metcalfe and his coworkers, exactly at their Palo Alto Research Center  (PARC) in California. It was meant for LAN communication. This version of Ethernet uses coaxial cables as a shared medium to connect devices together. It works at the speed of 2.94 Mb/s and supports only half-duplex type of connection. This technology was initially used only to connect Xerox’s devices, then in later versions, it became to expand and utilized by a variety of other companies. Furthermore, this version is best known for its bus topology. The following figure summaries this version characteristics.

In 1975, Robert Metcalfe and his coworkers ( David Boggs, Chuck Thacker, and Butler Lampson) were officially considered the inventors of Ethernet by means of having a patent application filed on the part of Xerox corporation.

In 1976, Metcalfe and Boggs published a seminal paper under the title "Ethernet: Distributed Packet Switching for Local Computer Networks" after the system was deployed at PARC.

In 1979, Metcalfe left Xerox to found 3Com Corporation, which was a digital electronics company that manufacturers computer networks products. The name of the company, as Metcalfe explained, is short of "Computer Communication Compatibility". As you notice there are three terms, each one with Com as a prefix, hence 3Com. Significantly, the company now no longer exists as a separate entity because it was absorbed by HP company in 2010 (Hewlett-Packard). Robert Metcalfe has always had the idea of promoting Ethernet technology as a standard so that it is used by a large number of networking devices manufacturers.

In 1980, to achieve the goal of promoting Ethernet as a standard, Metcalfe convinced Digital Equipment Corporation (DEC), Intel, and Xerox to work together for that. They later came up with a standard called "DIX Ethernet". DIX is a contraction of DEC, Intel, and Xerox.  In the same year, the three companies published the "Ethernet blue book". But Ethernet was not the only technology at that time, Token Ring and Token Bus were also developed for the same purpose. So, competetion among these technologies was severe because the three systems was submitted to be standardized. However, from that time up to now, Ethernet has become the dominant technology in LAN, MAN, and WAN connections.

In 1982, another version of Ethernet was developed by DIX consortium. They named it DIX Ethernet or Ethernet II. It is also referred to as Thinnet or 10Base2. This version works at the speed of 10Mb/s and use coaxial cable RG 58 terminated with BNC connectors as a shared medium to connect a multiple of nodes. The length of the cable extends to 185 m. Besides, this version of Ethernet also operate on Bus topology. As the time went on, new advancement had to be made in Ethernet standards. As a result, a new organization called IEEE has taken Ethernet with a view to develop it, for DIX stopped making amendment to Ethernet II. Thus, The last version that DIX consortium has developed was Ethernet II.

In 1983, an association called IEEE ( Institute of Electrical and Electronics Engineers) started a project to enhance and standardize the Ethernet invention. To initiate the development of the Ethernet, a group of engineers  have named their project "802". This number is now present as a stem in every technology developed by this group, including wireless and bluetooth. They only add numbers or letters to name other inventions. The first version of  Ethernet, called IEEE 802.3, was officially released in the same year.

In 1984, a company called IBM also introduced Token Ring, which is a technology with the same purpose, allowing data transmission at 4Mbps.  Although the high quality of its cables and connectors, it has lost favour with a lot of customers due to the large size and cost. Consequently, Ethernet has always been preferred over Token Ring. In the same year, another version of Ethernet, referred to as StarLAN, was in the process of development, to be standardized later.

In 1986, StarLAN was standardized by the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standards committee members as 802.3e, 1BASE5 version of Ethernet. The name StarLAN was derived from the fact that it  used a star topology from a central hub. It utilized unshielded twisted pair category 3 (UTP3)—the same simple cable used for telephone systems, which comprises four wires (two twisted pairs) running at a speed of 1 Mb/s. The devices used to connect the peripherals is a hub that is positioned in the middle and has port for each peripheral. This version of Ethernet uses Manchester coded signaling.

In 1987, LattisNet was introduced by SynOptics Communications (it is a computer network equipment manufacturer started in 1985 and ended in 1994, and founded  by Andrew K. Ludwick  and Ronald V. Schmidt, both of them worked at Xerox PARC. Its headquarters is in Santa Clara, California, US) as the first 10 implementation of 10 Mbs/s. LattisNet was the most important product of Synoptics Communications, and by means of employing unshielded twisted pair wiring in a star topology, Ethernet became later an omnipresent innovation. Besides, The company was also known for its network devices manufacture. This company created a fierce competition among other Ethernet LAN hubs' producers, such as 3Com and Cabletron, by being the market leader. It greatly paved the way for future Ethernet developments.

In 1990, the world has seen an introduction to the sophisticated 10BASE-T Ethernet version by IEEE, as  802.3i standard. It runs over four wires (two twisted pairs) on a CAT3 or CAT5 UTP (CAT=Category). The cable, with RJ-45 connector at either end, can be stretched to 100m, but not longer that. This version works at the speed of 10Mb/s which is obvious from the name 10BASE-T. This Ethernet standard uses a hub as an intermediary device to link nodes together, thus this connection is referred to as star topology.

The next lesson is a sequel to this one
10: Ethernet - Ethernet history part 2 Reviewed by BOUFTIRA on 4:11:00 PM Rating: 5

No comments:

All Rights Reserved by Computer Networks For All © 2015 - 2017

Contact Form


Email *

Message *

Powered by Blogger.