While pursuing his doctorate in computer science, Metcalfe took a job with MIT's
Project MAC after Harvard refused permission for him to connect the university to the then-new
ARPAnet. At MAC, Metcalfe was responsible for building some of the hardware that would link MIT's
minicomputers with ARPAnet. Metcalfe made ARPAnet the topic of his
doctoral thesis, but Harvard initially rejected it. Metcalfe decided how to improve his thesis while working at
Xerox PARC, where he read a paper about the
ALOHA network at the
University of Hawaiʻi. He identified and fixed some of the bugs in the AlohaNet model, then added that work to his revised thesis. It was then accepted by Harvard, which granted his PhD. Metcalfe was working at PARC in 1973 when he and
David Boggs invented
Ethernet, initially as a standard for connecting computers over short distances. He later recalled that Ethernet was born on May 22, 1973, the day he circulated a memo titled "Alto Ethernet" which contained a rough schematic of how it would work. "That is the first time Ethernet appears as a word, as does the idea of using
coax as
ether, where the participating stations, like in AlohaNet or ARPAnet, would inject their packets of data, they'd travel around at megabits per second, there would be collisions, and retransmissions, and back-off," Metcalfe explained. Boggs argued that another date was the birth of Ethernet: November 11, 1973, the first day the system actually functioned. a manufacturer of
computer networking equipment, in his
Palo Alto apartment. In 1980 he received the
ACM Grace Hopper Award for his contributions to the development of local networks, specifically Ethernet. In 1990, the 3Com board of directors appointed
Éric Benhamou as
CEO instead of Metcalfe, who then left the company. He became a
venture capitalist in 2001 and subsequently a
general partner at
Polaris Venture Partners. Metcalfe was a keynote speaker at the 2016 Congress of Future Science and Technology Leaders and, in 2019, he presented the
Bernard Price Memorial Lecture in South Africa. In June 2022, Metcalfe returned to MIT by joining the
Computer Science and Artificial Intelligence Laboratory as a research affiliate and computational engineer, working with the MIT
Julia Lab. ==Awards==