_(2).jpg)
Radia Perlman
1951–present · Computer Scientist and Network Engineer
An American computer scientist and network engineer whose work on Ethernet bridging and network routing made large computer networks more robust and scalable.
“Music is very similar to a network in that there are all these different instruments playing their own parts, and somehow it fits together wonderfully.”
Why is this scientist famous?
Designed the Spanning Tree Protocol, which prevents forwarding loops in bridged Ethernet networks and allowed Ethernet networks to grow far larger and more reliably.
Radia's story
A Childhood in Logic
Radia Joy Perlman was born on 18 December 1951 in Portsmouth, Virginia, and grew up in New Jersey. Both her parents were engineers — her father worked on radar systems, and her mother was a mathematician and computer programmer at a time when very few women entered those fields. Despite this technical household, Radia was not the kind of child who dismantled radios or built machines. She was drawn to puzzles, logic, and abstract reasoning. She attended the Massachusetts Institute of Technology, where she earned a bachelor's degree in mathematics in 1973 and a master's in mathematics in 1976. At the Massachusetts Institute of Technology (MIT), she became interested in how computers could be used to teach young children, helping develop a system called TORTIS that let pre-schoolers control a small robot turtle using physical buttons and command cards.
MIT and the Path to Networking
Perlman studied mathematics at MIT and also worked on educational computing, including the TORTIS system for very young children. She later moved into computer networking and became known for work on routing, bridging and network security. She completed her MIT doctorate in computer science in 1988; her doctoral research examined routing in networks that might contain faulty or malicious components.
The Spanning Tree Protocol
In the mid-1980s, while working at Digital Equipment Corporation (DEC), Perlman was handed a problem that would define her career. Network bridges — devices that connect two segments of a local network — were prone to forming loops, where data circulated endlessly and brought the network to a halt. Building larger bridged networks was nearly impossible because of this. Perlman was asked to design a protocol that could detect and disable loops automatically, using a constant amount of memory on each device regardless of how large the network was. She solved the problem in a matter of days. Her Spanning Tree Protocol (STP) allowed bridges to communicate with each other, map the network's topology, and block redundant paths — all without human intervention. The protocol was published in 1985 and became an IEEE standard in 1990. STP and its descendants became widely implemented in Ethernet switches and bridges.
Beyond STP
Perlman did not stop with STP. She recognised that her original protocol had limitations — it was slow to recover when the network topology changed, and it blocked paths that could have been used productively. Decades later, she was a key designer of TRILL (Transparent Interconnection of Lots of Links), a more sophisticated protocol that addressed these problems while preserving the simplicity that made STP so successful. She also made pioneering contributions to link-state routing protocols, the foundations of how routers share information about the network. After leaving DEC in 1993, she worked at Novell, Sun Microsystems, and Intel, and she has taught at Harvard and the University of Washington. She holds over 100 patents.
What did they discover?
Spanning Tree Protocol (1985)
An algorithm that allows network bridges to automatically detect and disable loops in a local area network, preventing data from circulating endlessly. STP became an IEEE standard and STP and its descendants became widely implemented in Ethernet switches and bridges.
TRILL Protocol
A successor to STP that allows multiple paths to be used simultaneously, improving network performance and resilience. Perlman was a key designer of TRILL to fix the limitations she identified in her original Spanning Tree Protocol.
TORTIS Educational System
An early hands-on programming system for preschool children. TORTIS used button boxes and picture-marked command cards in a slot-machine interface so children could control a small Logo turtle robot without typing computer code.
Amazing facts
She has sometimes been called the 'Mother of the Internet', a title she has rejected because the internet was created through the work of many people.
She devised the core spanning-tree algorithm while working at Digital Equipment Corporation in the mid-1980s and published the algorithm in 1985.
Her father was an engineer who worked on radar systems, and her mother was a mathematician and computer programmer.
As a child, she was not interested in taking things apart or building gadgets; she was drawn to abstract logic and mathematics.
Her PhD thesis from MIT addressed how to route data in networks where some nodes might be malicious — work that remains foundational to network security.
She was a key designer of TRILL to fix limitations in her original Spanning Tree Protocol.
She also helped develop TORTIS, an educational system that taught pre-schoolers programming concepts using button boxes and picture-coded command cards to control a turtle robot.
She holds over 100 issued patents in networking and computing.
Timeline
Born in Portsmouth, Virginia
Earned SB in Mathematics from MIT
Earned MS in Mathematics from MIT
Published her spanning-tree algorithm for extended local-area networks while working at Digital Equipment Corporation
Earned PhD in Computer Science from MIT
Spanning Tree Protocol became an IEEE standard (802.1D)
Left DEC to work at Novell and later Sun Microsystems
Inducted into the Internet Hall of Fame
Awards & honours
Related Super Scientists
Grace Hopper
1906–1992 · Computer Scientist & Naval Admiral
Developing one of the earliest compilers and pioneering word-based programming languages that helped make computers easier to program.
Ada Lovelace
1815–1852 · Mathematician
Publishing influential 1843 Notes on Charles Babbage's Analytical Engine, including a detailed algorithm for calculating Bernoulli numbers and a visionary description of uses beyond arithmetic.
Alan Turing
1912–1954 · Mathematician & Computer Scientist
Making foundational contributions to theoretical computer science and artificial intelligence, and playing a major role in Allied codebreaking during the Second World War.