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Jerry P. Becker

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Registered: 12/3/04
Brief History of Ethernet
Posted: Dec 20, 1999 9:36 PM
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Computerworld, June 21, 1999, p. 96 -- Technology Flashback (1973)

Ethernet Emerges

by Mary Brandel

Personal computers hadn't even hit the mass market when researchers started
working on what would later prove to be the second phase of the PC
revolution: linking these machines to a network. 1977 is widely seen as the
year of the PC's big arrival, but Ethernet - the technology that today ties
tens of millions of PCs into LANs - was invented four years earlier, in the
spring of 1973.

The source of this foresight was Xerox Corp.'s Palo Alto Research Center
(Parc). In 1972, Parc researchers were working on both a prototype of the
Alto computer [Flashback, June 14] - a personal workstation with a
graphical user interface - and a page-per-second laser printer. The plan
was for all Parc employees to have computers and to connect all of the
computers to the laser printer.

The task of creating the network was assigned to Bob Metcalfe, an MIT
graduate who had joined Xerox that year as the self-described "networking
guy." As Metcalfe says, the two novel requirements of this network were
that it had to be very fast to accommodate the laser printer and it had to
connect hundreds of computers.

Metcalfe's previous experience as a student gave him a great head start in
networking. "My Harvard Ph.D. dissertation, based on my research at MIT,
was about the Arpanet and the Alohanet," which was a packet radio network
at the University of Hawaii, he says.

By the end of 1972, Metcalfe and a number of other Parc researchers had
completed an experimental 3M bit/sec. PC LAN. The following year, Metcalfe
defined the general principles of what he called Ethernet, the technology
that made the first PC LAN possible. That same year marked the birth of the
first Ethernet board, which you could place in a PC to create a network.

Ethernet defines the wires-and-chips aspects of PC net-working as well as
the software aspects of how data is transmitted. A key concept is its
system of collusion-detection and recovery, called CSMA/CD, or Carrier
Sense Multiple Access with Collision Detect.

With this protocol, devices transmit only after finding the data channel
clear. If two devices transmit simultaneously, causing a collision, they
delay their retransmissions for a random length of time.

Metcalfe first called the network the "Alto Aloha Network." When he changed
the name, he based it on the idea of "lumeniferous ether," the medium that
scientists once thought carried electromagnetic waves through space.

Xerox produced hundreds of Ethernet boards that it used internally to
access the lab's central minicomputer, access the Arpanet, send and receive
e-mail, play games and share files, Metcalfe says.

It wasn't until 1979 that momentum gathered for Ethernet to become a widely
agreed upon 10M bit/sec. commercial standard. At that point, Metcalfe had
left Xerox and was meeting with Gordon Bell at Digital Equipment Corp.
about helping Digital create its own LAN. Instead of coming up with
something new, they decided to propose to Xerox that the two companies work
together to make Ethernet a standard.

By June, Metcalfe had gotten Intel Corp., Digital and Xerox to agree to
work on using Ethernet as the standard way of sending packets in a PC
network. "Only then did it dawn on me that Ethernet would be a successful
standard worth building a company around," Metcalfe says.

Thus 3Com Corp. was born. Now a $54 billion company, 3Com introduced its
first product, EtherLink - the first PC Ethernet network interface card, in
1982. Early 3Com customers included Trans-America Corp. and the White House.

Ethernet gained popularity in 1983 and was soon named an international
standard by the Institute of Electrical and Electronics Engineers Inc. But
one major computer force did not get on board: IBM, which developed a very
different LAN mechanism called Token Ring. Despite IBM's resistance,
Ethernet went on to become the most widely installed technology for
creating LANs. Today there's Fast Ethernet, which runs at 100M bit/sec.,
and Gigabit Ethernet, which promises 1G bit/sec. rates.

Looking back, Metcalfe says he would have used different methods to
convince IBM of Ethernet's merits.

"I would have recruited major IBM customers to help me demand it from IBM,"
he says. "And it didn't help that I routinely attacked IBM as being a
slow-moving monopoly - much as I now attack telephone companies and
Microsoft - so I have not learned my lesson entirely."
Brandel is a frequent contributor to Computerworld. Contact her at

Jerry P. Becker
Dept. of Curriculum & Instruction
Southern Illinois University
Carbondale, IL 62901-4610 USA
Fax: (618) 453-4244
Phone: (618) 453-4241 (office)
(618) 457-8903 (home)


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