Ethernet

What is Ethernet?

Ethernet is a type of network technology for local area networks; coaxial cable carries radio frequency signals between computers at a rate of 10 megabits per second. Ethernet consists of physical and data link layer technology for local area networks (LANs). In simple terms, it is a standard communications protocol embedded in software and hardware devices, intended for building a local area network (LAN). It utilises an advanced hardware technology through standard cables and adapters to link computers inside homes, schools and offices. It defines a number of wiring and signalling standards for the Physical Layer of the standard networking model. Most common type is the Ethernet over twisted pair to connect end systems and fiber optic versions for site backbones. The formal designation for standardization of the Ethernet protocol is sometimes referred to as IEEE 802.3. The IEEE (Institute of Electrical and Electronics Engineers) standardizes network protocols. Higher level network protocols like Internet Protocol (IP) use Ethernet as their transmission medium. Data travels over Ethernet inside protocol units called frames. The run length of individual Ethernet cables is limited to roughly 100 meters. The most common forms used are 10BASE-T, 100BASE-TX, and 1000BASE-T. All three utilize twisted pair cables and 8P8C modular connectors. They run at 10 Mbit/s, 100 Mbit/s, and 1 Gbit/s, respectively. Fiber optic variants of Ethernet offer high performance, electrical isolation and distance (tens of kilometres with some versions). In general, network protocol stack software will work similarly on all varieties.

A basic hard-wired LAN consists of the following components:

• 2 or more computers linked together or networked.
• A network interface card (NIC) in each computer.
• Ethernet cable connecting to each computer.
• A Networking Switch or Networking Hub directing network traffic.
• Networking software.

NIC is assigned a unique address. An Ethernet cable runs from each NIC to the central switch or hub. The switch or hub acts as a relay which receives and directs packets of data across the LAN. Ethernet networking thus creates a communications system that allows the sharing of data and resources, including printers, fax machines and scanners. Ethernet networks are not only wired, they exist in the form of wireless networking as well. In such a set up, there are wireless NICs which use radio waves for 2 way communication with a wireless switch or hub. Wireless NICs, switches and hubs each feature a small antenna instead of Ethernet ports.

History

Robert Melancton Metcalfe (Woodside, CA), a U.S. electrical engineer co invented Ethernet along with D.R. Boggs, (Palo Alto, CA), Charles P. Thacker (Palo Alto, CA), Butler W. Lampson (Portola Valley, CA) in 1973. It was developed at Xerox PARC (Palo Alto Research Centre). It was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his Ph.D. dissertation. During the 1970’s, Metcalfe was a member of the research staff for Xerox, at their PARC facility where world’s first personal computers were being developed. Metcalfe was assigned the duty to build a networking system for PARC's computers. Xerox was also building the world's first laser printer and wanted all of the PARC's computers to be able to print with this printer. Metcalfe now needed to develop a fast network to drive the very fast new laser printer and connect hundreds of computers within the same building. This feat had never been achieved before.

Metcalfe along with Xerox PARC’s team, consisting of above mentioned person, went on to develop a technology that could connect many computers over long distances. The original Ethernet sent roughly a paragraph of data over thick coaxial cable at a distance of one kilometre. Ethernet was named by Robert Metcalfe, for the passive substance called "luminiferous (light-transmitting) ether" that was once thought to pervade the universe, carrying light throughout. Ethernet was so- named to describe the way that cabling, also a passive medium could similarly carry data everywhere throughout the network.

Metcalfe later joined hands with Xerox, Digital Equipment Corporation (DEC) and Intel Corporation to create a 10-megabit-per-second (Mbps) standard, which was ratified by the Institute of Electrical and Electronics Engineers (IEEE). Through the efforts of Digital, Intel and Xerox ‘DIX’ Ethernet became the standard model for LANs worldwide during 1976.

In 1979, Metcalfe created his own business - 3Com Corporation to commercialize Ethernet. Initially, 3Com started building Ethernet circuit boards for minicomputers. During the early 1980s, Ethernet's 10BASE5, implementation used a coaxial cable 0.375 inches (9.5 mm) in diameter, later called ‘Thick Ethernet’ or ‘Thicknet’. Its successor, 10BASE2, known as ‘Thin Ethernet’ or ‘Thinnet’, used a cable similar to cable television cable of the era. Due to limitation of the cable, ‘Twisted-pair Ethernet’ was developed in the mid-1980s, with the development of StarLAN. UTP-based Ethernet became widely deployed with the 10BASE-T standard. This system replaced the coaxial cable systems with a system of full duplex switches linked via UTP. And in 1982, it released an Ethernet card (plug-in circuit board) for the IBM personal computer (PC).This was a turning point for development in PC’ as these gave PCs the convenience, efficiency, and power of computer networks.

In 1990 the 10BASE-T standard was introduced. Ethernet switches supplemented the half duplex CSMA/CD scheme with a full duplex system offering higher performance at a lower cost than routers. With the arrival of 100BASE-T, Ethernet switches capable of mixed speed and mixed duplex operation were built. The same year, the true potential of Ethernet was unleashed when the World Wide Web was developed by Tim Berners-Lee, a British computer scientist.

Development in the Invention of the Ethernet

It helped in the development of ‘Asynchronous Transfer Mode’ (ATM) technology. ATM allowed devices to be connected over very wide distances to create WANs (wide area networks) that worked like LANs.

Ethernet networks started growing larger, faster, and more diverse. Ethernet now has 4 standard speeds: 10 Mbps (10 Base-T), 100 Mbps (Fast Ethernet), 1,000 Mbps (Gigabit Ethernet), and 10,000 Mbps (10-Gigabit Ethernet). Each new standard does not make the older ones obsolete, however. An Ethernet controller runs at the speed of the slowest connected device, which is helpful when mixing old and new technology on the same network.

Networking advances IEEE 802.1aq (SPB) has been developed which uses the link-state routing protocol IS-IS to allow larger networks with shortest path routes between devices.

Wireless networks were developed consequently which are more flexible to use.

Role of the Invention of the Ethernet in the Improvement of Human Life

• Ethernet provides more speed, flexibility and diversity as compared to LAN.
  
  
• Ethernet introduced the standardization of networking, equipment and tools by the PC industry.
  
  
• Due to its fast speed and other features Ethernet Networking has enabled effective communication and business.
  
  
• Ethernet can be easily extended to WAN which makes it quite simple for IT managers to incorporate high-end features in the organization’s LAN.
• Ethernet allows multiplexing protocols over a single wire. Although the most-common protocol to run on Ethernet is IP, other protocols can use Ethernet.