The Genius Behind Ethernet: Unveiling Its Inventor

Discover the Inventor and History of Ethernet Technology in Our Latest Article. Unveil the Genius Behind Its Invention.
The Genius Behind Ethernet Unveiling Its Inventor

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On April 7, 1946, a baby boy was born to an ordinary family in Brooklyn, New York, just a year after the end of World War II. The father of the baby boy was a technician at a gyroscope factory, while his mother was a homemaker. For this family, who had just gone through tumultuous times of war, the birth of their child brought great joy.

The couple had high hopes for their son, hoping that he would excel and become a top engineer, a highly esteemed profession at the time. Their hopes were not in vain, as the boy, named Metcalfe, showed exceptional talent in his studies as he grew older. In 1964, he graduated from high school and was accepted into the most prestigious engineering institution in the US, the Massachusetts Institute of Technology (MIT).

Metcalfe’s parents could not have imagined that their child would not only become a top engineer but also go on to found a Fortune 500 company. His great invention, which changed the lives of countless people and had a profound impact on the IT industry, was none other than Ethernet technology. Metcalfe went on to found the renowned tech company, 3Com and proposed Metcalfe’s Law.

Robert Melancton Metcalfe, the inventor of Ethernet technology, founder of 3Com, and proposer of Metcalfe’s Law, is the embodiment of the American Dream, and his story is one of perseverance, talent, and innovation.


▮ Fledgling Scholar’s Initial Struggle: Doctoral Thesis Rejected

In 1969, at the age of 23, Metcalfe graduated from the Massachusetts Institute of Technology with degrees in Electrical Engineering and Business Management. A year later, he received a Master’s degree in Computer Science from Harvard University and continued to pursue a Ph.D. at the same institution.

While pursuing his Ph.D., Metcalfe secured a job at the MAC project group at MIT. This group was well-known for its research in operating systems, computing theory, and artificial intelligence.

In the same year, the U.S. Department of Defense launched ARPANET, the precursor to the internet, which connected the large computers of four prestigious universities.

Metcalfe saw the potential of this development and proposed to Harvard and MIT that their own large computer systems should also be connected to ARPANET (as he was both a Harvard graduate student and a research scientist at MIT).

While Harvard arrogantly rejected his proposal, MIT agreed.

Soon, Metcalfe successfully built the network interface, connecting MIT’s large computer to ARPANET.

Drawing on his own design and research (establishing a high-speed network interface and protocol software between ARPANET IMP and PDP-10 time-sharing minicomputers), he wrote a Ph.D. thesis and submitted it to Harvard’s degree committee.

However, in June 1972, Metcalfe’s thesis defense failed because the committee found his thesis lacked “mathematical” and “theoretical” rigor.

The setbacks didn’t just come from Harvard. During his involvement in the ARPANET project, Metcalfe led 10 officials from American Telephone and Telegraph (AT&T) on a tour of the ARPANET demonstration. Unfortunately, the system crashed during the presentation.

Metcalfe wrote in recollection, “I looked up in agony and saw them snickering at the unreliability of packet switching… I will never forget that. To them, it confirmed that circuit switching (the technology used in traditional telephone systems) would continue to exist and that packet switching was an unreliable toy that would never have much impact on the business world.”

These successive setbacks left Metcalfe feeling a bit disheartened. Soon after, he received a warm invitation from Bob Taylor, the director of the Xerox Palo Alto Research Center (PARC), and one of the founders of ARPANET, to join the lab and complete his own research. Metcalfe readily accepted.

The PARC lab in Palo Alto is famously known as PARC.


PARC laboratory gave birth to many great inventions, such as laser printers, the mouse, graphical user interfaces (GUI), bitmap graphics, and more. Many of the innovations that made Apple computers stand out came from PARC.

▮ Chance Encounter with a Colleague Sparks Inspiration and Leads to Project Success

After arriving at PARC, Metcalfe quickly began his work. At the time, PARC was trying to design the world’s first personal computer (later known as the Alto). Metcalfe’s task was to design a networking interface for this computer that would allow them to be connected to each other. The biggest challenge in building a multi-user terminal computer network was how to coordinate the access of different computer hosts to the network.


In the early 1960s, computer scientist Leonard Kleinrock proposed using queuing theory from mathematics to coordinate data flow in a network by simulating traffic congestion and people queuing up. ARPANET adopted this theory and proved its effectiveness.

In 1971, Norman Abramson, a professor at the University of Hawaii, established a wireless network called ALOHAnet (ALOHA is a common Hawaiian greeting), which used a more “radical” approach than ARPANET.

In ALOHAnet, data was transmitted in the form of tiny data packets. It did not try to avoid conflicts between packets. Instead, any user whose message was lost due to a conflict could simply retry sending the packet at a random time interval.


It’s like two people talking. If both start talking at the same time, they will immediately stop. Later, they will restart the conversation. After several attempts, there will always be a situation where one person doesn’t talk, and the problem is solved.

It can be noticed that the strategy of ALOHAnet has an obvious flaw: it wastes resources. This approach is useful in low-traffic situations, but when the network becomes crowded, collisions will become frequent and transmission efficiency will drop significantly.

After reading Norman Abramson’s paper, Metcalfe was inspired. Soon, he improved the model of ALOHAnet and proposed a new model.

In the new model, computer hosts independently adjust the waiting time for transmission retries based on the frequency of collisions. If the number of collisions is low, they will quickly retry; if the network is congested, they will drop out to maintain overall communication efficiency.

Metcalfe’s new model filled the gap in his own paper. Finally, in May 1973, he passed the defense of his doctoral thesis at Harvard University and obtained his doctorate degree. (It is worth mentioning that Harvard University did not publish his paper, but MIT did, which made Metcalfe very upset.)

In his research project, Metcalfe also introduced the new model.

On May 22, 1973, Metcalfe distributed a memo called “Alto Ethernet,” formally proposing the concept of Ethernet.

In the memo, Metcalfe drew a diagram of the working principle of Ethernet. He proposed, “Participating sites, such as AlohaNet or ARPAnet, inject their packets, which propagate at a speed of one megabit per second, with collisions, retransmissions, and backoffs.”


Metcalfe’s Ethernet vision combined Norman Abramson’s random retry mechanism, his own adjustments to the system clock, and other improvements to the ALOHAnet model to reduce the impact of collisions.

Some of these theoretical innovations were developed by other researchers, but Metcalfe was the first to integrate them into practical network design.

As for the origin of the name “Ethernet,” it’s worth explaining. Before the discovery of electromagnetic waves, people proposed the existence of a medium called “ether,” which was thought to be ubiquitous (light was believed to be transmitted through it). Later, it was discovered that ether doesn’t actually exist.

Metcalfe adopted the name “Ethernet,” treating it as a medium for transmission. He also acquired a nickname, “Ether Daddy.”

In June 1973, Metcalfe was granted permission to build a prototype Ethernet with 100 nodes.

To complete the complex work of logic design, circuit board construction, microcode programming, and more, Metcalfe enlisted the help of Stanford graduate student David R. Boggs.


Metcalfe (left) and Boggs (right)

On November 11, 1973, thanks to the efforts of Metcalfe and Boggs, the world’s first Ethernet prototype system was officially born. At that time, the transmission speed of this Ethernet reached 2.94 megabits per second, which was about 10,000 times faster than previous terminal networks.

▮ Founding 3Com and Promoting the Popularization of Ethernet

After the development of Ethernet technology, Metcalfe strongly recommended Xerox to commercialize the technology. However, the response from Xerox’s management was slow and they didn’t take any action for six years. In 1979, Metcalfe couldn’t take it anymore and left the PARC laboratory. He decided to start his own company to promote the adoption of Ethernet technology. This company later became the famous communication network enterprise, 3Com.


The name “3Com” comes from the three letters: “computer,” “communication,” and “compatibility,” which reflect Metcalfe’s desire to improve computer communication compatibility.

After 3Com was founded, the company greatly improved the commercial viability of Ethernet by selling network software, Ethernet transceivers, and Ethernet cards for small computers and workstations.

In 1980, through Metcalfe’s facilitation, the world’s second-largest computer company, Digital Equipment Corporation (DEC), semiconductor company Intel, and large system supplier Xerox formed a technical alliance and launched the DIX (named after the first letter of each company) Ethernet standard.

Soon after, in 1983, IEEE established a working group and launched the IEEE 802.3 standard, which is a variant of the DIX standard.

The earliest 802.3 standard was 10BASE5, which had a throughput of only 10 Mbps and used thick coaxial cable, as well as a carrier sense multiple access with collision detection (CSMA/CD) access control method.

In addition to Ethernet, IBM and General Motors also introduced their own network standards. IBM’s token ring technology, in particular, competed fiercely with Ethernet. Ultimately, after 20 years of competition, Ethernet emerged victorious, and the token ring was phased out.

▮ Retirement and Transition after Achieving Fame and Success

Throughout the 1980s, Metcalfe worked on promoting the adoption of Ethernet. On March 21, 1984, 3Com went public, and Metcalfe’s company was successful.

In the mid-1980s, Metcalfe proposed a critical observation: “The value of a network is proportional to the square of the number of nodes in the network.” This observation is now known as “Metcalfe’s Law” and is essential for understanding network effects and the development of the Internet economy.

In 1990, Metcalfe left 3Com and became a commentator and technology columnist. During this time, Metcalfe made several mistakes, and some of his strange statements often made him the target of media ridicule.

In 1995, Metcalfe predicted that the Internet would face a “catastrophic collapse” the following year. He promised to “eat his words” if he was wrong. In the end, he did indeed make a mistake, and in 1997, at the Sixth International World Wide Web Conference, he printed out his article, blended it with some liquid, and ate the resulting slurry in front of the audience, admitting his error.

Metcalfe’s other incorrect predictions included that Linux would be killed by Windows 2000, that wireless networks would be abandoned in the mid-1990s, and that Windows and Linux would be unable to handle video traffic by 2006.

In 1984, 3Com, the company co-founded by Bob Metcalfe, went public. Throughout the 1980s, Metcalfe worked to popularize Ethernet, and in the mid-1980s, he proposed “Metcalfe’s Law,” which states that the value of a network is proportional to the square of the number of nodes in the network. This law has been important in understanding network effects and the development of the Internet economy.

Metcalfe left 3Com in 1990 and became a commentator and technology columnist. He made some strange statements during this time that often made him the subject of media ridicule. In 1995, Metcalfe predicted that the internet would suffer a “catastrophic collapse” the following year, and he promised to eat his words if he was wrong. He was proven wrong, and in 1997, he brought a printed copy of his article to the Sixth International World Wide Web Conference, put it in a blender with some liquid, and ate the resulting paste as the audience cheered.

Metcalfe’s other incorrect predictions included that Linux would be killed off by Windows 2000, wireless networks would be abandoned in the mid-1990s, and that Windows and Linux would be unable to handle video by 2006.

In 2001, Metcalfe left the media industry and founded Polaris Venture Partners, a venture capital firm. In 2011, he became a professor at the University of Texas at Austin. In 2022, more than 50 years after he first worked there, Metcalfe returned to MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) as a researcher.

During this time, 3Com also went through some ups and downs. In 1999, the company’s revenue reached a peak of $5.7 billion, but the dot-com bubble soon burst, and 3Com fell from grace, with its market value plummeting. In November 2009, Hewlett-Packard acquired 3Com for $2.7 billion in cash, and the company exited the stage of history.

In his later years, Metcalfe received numerous awards for his significant contributions to Ethernet. In 1996, he was awarded the IEEE Medal of Honor. In 2003, he received the National Medal of Technology and the Marconi Prize. In 2007, he was inducted into the National Inventors Hall of Fame.

Most recently, on March 22, 2023, 76-year-old Metcalfe was awarded the 2022 Turing Award by the Association for Computing Machinery (ACM), with a prize of $1 million from Google. Jeff Dean, senior vice president at Google for Research and AI, said in an official statement from the ACM, “Today, there are roughly 7 billion network ports worldwide. Ethernet is everywhere, and we take it for granted. However, it’s easy to forget that without Bob Metcalfe’s invention and effort (that is, every computer needing to be networked), our interconnected world wouldn’t be what it is today.”

Words in the end

Jeff Dean is right. Ethernet technology is the cornerstone of people’s data communication networks. As the father of Ethernet, Metcalfe’s contribution was enormous.

Today, Ethernet remains the main standard for wired network communication worldwide. Its data processing speed has increased from 2.94Mbps, 10Mbps, all the way up to 400Gbps, 800Gbps, and even 1.6Tbps.


802.3, a familiar number to us, will accompany us for a long time until the day it is replaced.

Well, that’s all for today’s article. Thank you for reading patiently. If you think it’s well-written, please share and support it! Thank you!


  1. “Ethernet inventor Bob Metcalfe wins Turing Award,” The Paper;
  2. “Turing Award presented to father of Ethernet!” Synced Review;
  3. “50th anniversary of Ethernet: Ethernet father wins Turing Award and 2023 roadmap released,” SDNLAB;
  4. Wikipedia entry.
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