Ethernet

Robert M. Metcalfe and his associates at the Xerox Palo Alto Research Center (Xerox PARC)

first developed both the concept of a local area network (LAN) and the enabling technology.That first network originally was known as the Altos Aloha Network, because it connected Altos computers through a network based on the University of Hawaii’s AlohaNet packet radio system technology. Subsequently (1973), it was renamed Ethernet, from luminiferous ether, the omnipresent passive medium once theorized to pervade all space and to support the propagation of electromagnetic energy.The original Ethernet supported a transmission rate of 2.94 Mbps over coaxial cable. Xerox commercialized the technology, renaming it the Xerox Wire. Gordon Bell, vice president of engineering at Digital Equipment Corporation (DEC, subsequently acquired by Compaq, which later merged with Hewlett-Packard), hired Metcalfe as a consultant in 1979 specifically to develop a LAN network technology that would not conflict with the Xerox patent. Metcalfe brought DEC, Intel, and Xerox together to form into a joint venture known as DIX, which improved the technology, increasing the bandwidth to 10 Mbps and reverting to the name Ethernet.The technology quickly became a de facto standard. In February 1980, the IEEE established Project 802 to develop a set of LAN standards. In December 1982, the first standard was published and circulated as IEEE 802.3, which actually is a variation on the now obsolete Ethernet standard. Although the two do not interoperate, the terms 802.3 and Ethernet are used interchangeably in informal conversation.

Ethernet has evolved considerably since 1980. The signaling rate has increased from 10 Mbps to 100

Mbps, 1 Gbps, and 10 Gbps. The original 10Base5 specification for coaxial cable has given way to 10/100/1000Base-T specifications for twisted pair, and various 10GBase-XX specifications for optical

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• cell
• cell delay variation (CDV)
• cell delay variation tolerance (CDVT)
• cell error ratio (CER)
• cell loss priority (CLP)
• cell loss ratio (CLR)
• cell misinsertion rate (CMR)
• cell tax
• cell tax
• cell tax
• cell transfer delay (CTD)
• Cellular Digital Packet Data (CDPD)
• cellular radio
• CELP (Code Excited Linear Prediction)
• CEN
• CENELEC
• centimeter (cm)
• centralized attendant service (CAS)
• central office (CO)
• central office exchange code
• central office exchange (COE)
• central office prefix
• central processing unit (CPU)
• Centrex (CTX)
• centum call seconds (CCS)