https://spectrum.ieee.org/ethernet-ieee-milestone


Ethernet is Still Going Strong After 50 Years

The technology has become the standard LAN worldwide

By JOANNA GOODRICH  16th NOV 2023


The Xerox Palo Alto Research Center in California has spawned many pioneering 
computer technologies including the Alto—the first personal computer to use a 
graphical user interface—and the first laser printer.

The PARC facility also is known for the invention of Ethernet, a networking 
technology that allows high-speed data transmission over coaxial cables.

Ethernet has become the standard wired local area network around the world, and 
it is widely used in businesses and homes. It was honored this year as an IEEE 
Milestone, a half century after it was born.

Connecting PARC’s Alto computers

Ethernet’s development began in 1973, when Charles P. Thacker—who was working 
on the design of the Alto computer—envisioned a network that would allow Altos 
to communicate with each other, as well as with laser printers and with PARC’s 
gateway to the ARPANET.

PARC researcher Robert M. Metcalfe, an IEEE Fellow, took on the challenge of 
creating the technology. Metcalfe soon was joined by computer scientist David 
Boggs.

Metcalfe and Boggs had two criteria: The network had to be fast enough to 
support their laser printer, and it had to connect hundreds of computers within 
the same building.

The Ethernet design was inspired by the Additive Links On-line Hawaii Area 
network (ALOHAnet), a radio-based system at the University of Hawai’i. 
Computers transmitted packets, prefaced by the addresses of the recipients, 
over a shared channel as soon as they had information to send. If two messages 
collided, the computers that had sent them would wait a random interval and try 
again.

Metcalfe outlined his proposal, then called the Alto Aloha Network, in a 
now-famous memo to his colleagues. Using coaxial cables rather than radio waves 
would allow faster transmission of data and limit interference.

The cables also meant that users could join or exit the network without having 
to shut off the entire system, Metcalfe said in a 2004 oral history conducted 
by the IEEE History Center.

“There was something called a cable television tap, which allows one to tap 
into a coax without cutting it,” Metcalfe said. “Therefore, [Boggs and I] chose 
coax as our means of communication. In [the] memo, I described the principles 
of operation—very distributed, no central control, a single piece of ‘ether.’”

Metcalfe and Boggs designed the first version of what is now known as Ethernet 
in 1973. It sent data at up to 2.94 megabits per second and was “fast enough to 
feed the laser printer and easy to send through the coax,” Metcalfe told the 
IEEE History Center.

A 9.5-millimeter thick and stiff coaxial cable was laid in the middle of a hall 
in the PARC building. The 500-meter cable had 100 transceiver nodes attached to 
it with N connectors, known as vampire taps.

Each of the taps—small boxes with a hard shell—had two probes that “bit” 
through the cable’s outer insulation to contact its copper core. Thus new nodes 
could be added while existing connections were live.

Each vampire tap had a D-type connector socket in it, consisting of a plug with 
nine pins that matched to a socket with nine jacks. The sockets allowed Alto 
computers, printers, and file servers to attach to the network.

To enable the devices to communicate, Metcalfe and Boggs created the first 
high-speed network interface card (NIC)—a circuit board that is connected to a 
computer’s motherboard. It included what is now known as an Ethernet port.

The researchers changed the name from the original Alto Aloha Network, to 
Ethernet, to make it clearer that the system could support any computer. It 
reflected a comment Thacker had made early on, that “coaxial cable is nothing 
but captive ether,” PARC researcher Alan Kay recalled.

Metcalfe, Boggs, Thacker, and Butler W. Lampson were granted a U.S. patent in 
1978 for their invention.

They continued to develop the technology and, in 1980, PARC released Ethernet 
that ran at 10 Mb/s. The update was done in collaboration with researchers at 
Intel and the Digital Equipment Corp. (DEC) to create a version of Ethernet for 
broad industry use, according to the Milestone entry.

Becoming an IEEE standard

Ethernet became commercially available in 1980 and quickly grew into the 
industry LAN standard. To provide computer companies with a framework for the 
technology, in June 1983 Ethernet was adopted as a standard by the IEEE 802 
Local Area Network Standards Committee.


Currently, the IEEE 802 family consists of 67 published standards, with 49 
projects under development. The committee works with standards agencies 
worldwide to publish certain IEEE 802 standards as international guidelines.

A plaque recognizing the technology will be displayed outside the PARC 
facility. It will read:

Ethernet wired LAN was invented at Xerox Palo Alto Research Center (PARC) in 
1973, inspired by the ALOHAnet packet radio network and the ARPANET. In 1980 
Xerox, DEC, and Intel published a specification for 10 Mbps Ethernet over 
coaxial cable that became the IEEE 802.3-1985 Standard. Later augmented for 
higher speeds, and twisted-pair, optical, and wireless media, Ethernet became 
ubiquitous in home, commercial, industrial, and academic settings worldwide.

Administered by the IEEE History Center and supported by donors, the Milestone 
program recognizes outstanding technical developments around the world. The 
IEEE Santa Clara Valley Section sponsored the nomination.



READER COMMENTS

Richard Bennett  23 NOV, 2023

I don't want to rain on anybody's parade, but the only thing today' Ethernet 
has in common with PARC Ethernet is the name. We don't rely on a single-speed 
coaxial cable backbone and we don't use CSMA/CD. Instead of putting a radio 
network inside a cable, we decided that we should put active electronics at 
both ends of each network port. This allowed us to isolate faults and 
mix-and-match speeds and cables. It also enabled full duplex communication 
without any nasty collisions. 10BASE-T broke new ground.


Laurence Parry 18 NOV, 2023

As a measure of its success, I recently bought both an Ethernet cable and a 
port. The latter, however, was 1Gb; while I have a 2.5Gb motherboard, I doubt 
I'll reach the cable's 40Gb in my lifetime. After all, 8K 120Hz HEVC uses at 
most 250Mbps. WiFi 6+ can handle that, without cables.

Much revenue is in the datacenter at speeds of 100Mbit+ but there were 200M 
1/2.5Gb ports shipped in Q2; mostly 1Gb. Let's hope 5Gb comes faster than 
2.5Gb, or the home market may swiftly degrade. Many laptops already go without.

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