American software designer and network engineer
Radia Joy Perlman
(
;
[1]
born December 18, 1951) is an American computer programmer and network engineer. She is a major figure in assembling the networks and technology to enable what we now know as the internet. She is most famous for her invention of the
Spanning Tree Protocol
(STP), which is fundamental to the operation of
network bridges
, while working for
Digital Equipment Corporation
, thus earning her nickname "Mother of the Internet".
[2]
Her innovations have made a huge impact on how networks self-organize and move data. She also made large contributions to many other areas of network design and standardization: for example, enabling today's
link-state routing protocols
, to be more robust, scalable, and easy to manage.
Perlman was elected a member of the
National Academy of Engineering
in 2019 for contributions to Internet routing and bridging protocols.
[3]
She holds over 100 issued patents. She was elected to the
Internet Hall of Fame
in 2014, and to the
National Inventors Hall of Fame
in 2016.
[4]
[5]
She received lifetime achievement awards from
USENIX
in 2006 and from the
Association for Computing Machinery
’s
SIGCOMM
in 2010.
[6]
[7]
More recently she has invented the
TRILL
protocol to correct some of the shortcomings of spanning trees, allowing Ethernet to make optimal use of bandwidth. As of 2022, she was a Fellow at
Dell Technologies
.
[8]
Early life
[
edit
]
Perlman was born in 1951
,
Portsmouth, Virginia
. She grew up in
Loch Arbour, New Jersey
.
[9]
She is Jewish.
[10]
Both of her parents worked as
engineers
for the US government. Her father worked on
radar
and her mother was a mathematician by training who worked as a
computer programmer
. During her school years Perlman found math and science to be “effortless and fascinating”, but had no problem achieving top grades in other subjects as well. She enjoyed playing the piano and
French horn
. While her mother helped her with her math homework, they mainly talked about literature and music. But she didn't feel like she fit underneath the stereotype of an "engineer" as she did not break apart computer parts.
[11]
Despite being the best science and math student in her school it was only when Perlman took a programming class in high school that she started to consider a career that involved computers. She was the only woman in the class and later reflected "I was not a hands-on type person. It never occurred to me to take anything apart. I assumed I'd either get electrocuted, or I'd break something".
[12]
She graduated from
Ocean Township High School
in 1969.
[13]
Education
[
edit
]
As an undergraduate at
MIT
Perlman learned programming for a physics class. She was given her first paid job in 1971 as part-time programmer for the
LOGO
Lab at the (then) MIT Artificial Intelligence Laboratory, programming
system software
such as
debuggers
.
[11]
Working under the supervision of
Seymour Papert
, she developed a child-friendly version of the educational robotics language LOGO, called TORTIS ("Toddler's Own Recursive Turtle Interpreter System"). During research performed in 1974?76, young children?the youngest aged 3½ years, programmed a LOGO educational robot called a Turtle. Perlman has been described as a pioneer of teaching young children computer programming.
[14]
Afterwards, she was inspired to make a new programming language that would teach much younger children similar to Logo, but using special "keyboards" and input devices. This project was abandoned because "being the only woman around, I wanted to be taken seriously as a 'scientist' and was a little embarrassed that my project involved cute little kids". MIT media project later tracked her down and told her that she started a new field called
tangible user interface
from the leftovers of her abandoned project.
[11]
As a math grad at MIT she needed to find an adviser for her thesis, and joined the MIT group at
BBN Technologies
. There she first got involved with designing
network protocols
.
[11]
Perlman obtained a B.S. and M.S. in Mathematics and a Ph.D. in
Computer Science
from
MIT
in 1988.
[15]
Her doctoral thesis on routing in environments where malicious network failures are present serves as the basis for much of the work that now exists in this area.
[2]
When studying at MIT in the late 60s she was one among the 50 or so women students, in a class of about 1,000 students. To begin with MIT only had one women’s dorm, limiting the number of women students that could study. When the men’s dorms at MIT became
coed
Perlman moved out of the women’s dorm into a mixed dorm, where she became the "resident female". She later said that she was so used to the gender imbalance, that it became normal. Only when she saw other women students among a crowd of men she noticed that "it kind of looked weird".
[11]
Career
[
edit
]
After graduation, she accepted a position with Bolt, Berenek, Newman (BBN), a government contractor that developed software for network equipment. While working for BBN, Perlman made an impression on a manager for Digital Equipment Corp and was offered a job, joining the firm in 1980. During her time working at Digital, she quickly produced a solution that did exactly what the team wanted it to; the Spanning Tree Protocol. It allows a network to deliver data reliably by making it possible to design the network with redundant links. This setup provides automatic backup paths if an active link fails, and disables the links that are not part of the tree. This leaves a single, active path between any pair of network nodes.
[2]
She is most famous for STP, which is fundamental to the operation of
network bridges
in many smaller networks. Perlman is the author of a textbook on networking called “Interconnections: Bridges, Routers, Switches, and Internetworking Protocols” and coauthor of another on network security called “Network Security: Private Communication in a Public World”, which is a now popular college textbook. Her contributions to network security include trust models for Public Key Infrastructure, data expiration, and distributed algorithms resilient despite malicious participants.
[16]
She left Digital in 1993 and joined
Novell
. Then, in 1997 she left Novell and joined
Sun Microsystems
. Over the course of her career she has earned over 200 patents, 40 of them while working for Sun Microsystems, where in 2007 she held the title of Distinguished Engineer.
[17]
She has taught courses at the
University of Washington
,
Harvard University
,
MIT
, and
Texas A&M
, and has been the keynote speaker at events all over the world. Perlman is the recipient of awards such as Lifetime Achievement awards from USENIX and the Association for Computing Machinery’s Special Interest Group on Data Communication (SIGCOMM).
[18]
Spanning Tree Protocol
[
edit
]
Perlman invented the spanning tree algorithm and protocol. While working as a consulting engineer at
Digital Equipment Corporation
(DEC) in 1984 she was tasked with developing a straightforward protocol that enabled
network bridges
to locate loops in a
local area network
(LAN). It was required that the protocol should use a constant amount of memory when implemented on the network devices, regardless of how large the network was. Building and expanding bridged networks was difficult because loops, where more than one path leads to the same destination, could result in the collapse of the network. Redundant paths in the network meant that a bridge could forward a frame in multiple directions. Therefore loops could cause
Ethernet frames
to fail to reach their destination, thus flooding the network. Perlman utilized the fact that bridges had unique 48 bit
MAC addresses
, and devised a network protocol so that bridges within the LAN communicated with one another. The algorithm implemented on all bridges in the network allowed the bridges to designate one
root bridge
in the network. Each bridge then mapped the network and determined the shortest path to the root bridge, deactivating other redundant paths. Despite Perlman's concerns that it took the spanning tree protocol about a minute to react when changes in the
network topology
occurred, during which time a loop could bring down the network, it was standardized as 802.1d by the
Institute of Electrical and Electronics Engineers
(IEEE). Perlman said that the benefits of the protocol amount to the fact that "you don't have to worry about topology" when changing the way a LAN is connected. Perlman has however criticized changes which were made in the course of the standardization of the protocol.
[19]
From the paper "An Algorithm for Distributed Computation of a Spanning Tree in an Extended LAN":
[1]
ⓒ 1985 ACM, copied from
ACM SIGCOMM Computer Communication Review Volume 15 Issue 4 Sept. 1985
with permission of the ACM.
- Algorhyme
- I think that I shall never see
- A graph more lovely than a tree.
- A tree whose crucial property
- Is loop-free connectivity.
- A tree which must be sure to span
- So packets can reach every LAN.
- First the root must be selected.
- By ID it is elected.
- Least cost paths from root are traced.
- In the tree these paths are placed.
- A mesh is made by folks like me
- Then bridges find a spanning tree.
Other network protocols
[
edit
]
Perlman was the principal designer of the
DECnet
IV and V protocols, and
IS-IS
,
[20]
the
OSI
equivalent of
OSPF
. She also made major contributions to the
Connectionless Network Protocol
(CLNP). Perlman has collaborated with
Yakov Rekhter
on developing
network routing
standards, such as the OSI Inter-Domain Routing Protocol (IDRP),
[21]
the OSI equivalent of
BGP
. At DEC she also oversaw the transition from
distance vector
to
link-state routing protocols
. Link-state routing protocols had the advantage that they adapted to changes in the network topology faster, and DEC's link-state routing protocol was second only to the link-state routing protocol of the
Advanced Research Projects Agency Network
(ARPANET). While working on the
DECnet
project Perlman also helped to improve the
intermediate-system to intermediate-system
routing protocol, known as
IS-IS
, so that it could route the
Internet Protocol
(IP),
AppleTalk
and the
Internetwork Packet Exchange
(IPX) protocol.
[19]
The
Open Shortest Path First
(OSPF) protocol relied in part on Perlman's research on fault-tolerant broadcasting of routing information.
[22]
Perlman subsequently worked as a network engineer for
Sun Microsystems
, now
Oracle
. She specialized in network and security protocols and while working for Oracle and obtained more than 50 patents.
[12]
Awards
[
edit
]
Bibliography
[
edit
]
- Perlman, Radia (1999).
Interconnections: Bridges, Routers, Switches, and Internetworking Protocols
(2 ed.).
Addison-Wesley
Professional Computing Series.
ISBN
978-0-201-63448-8
.
- Perlman, Radia; Kaufman, Charlie; Speciner, Mike; Perlner, Ray (2022).
Network Security: Private Communication in a Public World
(3 ed.).
Addison-Wesley
Professional.
ISBN
978-0-13-664360-9
.
References
[
edit
]
- ^
"Making Data Flow: The Radia Perlman Story"
.
National Inventors Hall of Fame
. May 9, 2016
. Retrieved
September 2,
2022
.
- ^
a
b
c
"Radia Perlman Spanning Tree Protocol"
.
NAE Website
. Retrieved
July 20,
2021
.
- ^
"Dr. Radia J. Perlman"
.
National Academy of Engineering
. Retrieved
June 30,
2023
.
- ^
"Radia Perlman"
.
Internet Hall of Fame
. Retrieved
June 30,
2023
.
- ^
"Radia Perlman: Robust Network Routing and Bridging"
. National Inventors Hall of Fame. 2016
. Retrieved
June 30,
2023
.
- ^
"Flame Award"
. USENIX. December 6, 2011
. Retrieved
June 30,
2023
.
- ^
"SIGCOMM Award Recipients"
. ACM SIGCOMM
. Retrieved
June 30,
2023
.
- ^
Kaufman, Charlie; Perlman, Radia; Speciner, Mike; Perlner, Ray (September 15, 2022).
Network Security: Private Communication in a Public World (Prentice Hall Series in Computer Networking and Distributed Systems) 3rd Edition
. Addison-Wesley.
ISBN
978-0136643609
.
- ^
"Music Winners Feted"
,
Red Bank Register
, December 27, 1968. Accessed September 20, 2021. "Mrs. Benjamin Nebman, 1308 Edgewood Ave., hosted a party in her home to honor her students Adrienne Wigdortz, Wanamassa, and Radia Perlman, Loch Arbour, who were two of the winners of the Monmouth Arts Foundation Merit Award for piano."
- ^
"Radia Perlman"
.
- ^
a
b
c
d
e
Salim, Nancy (October 18, 2010).
"Radia Perlman: Don't Call Me the Mother of the Internet"
.
The Atlantic
. Retrieved
March 20,
2018
.
- ^
a
b
Salim, Nancy (October 18, 2010). "Meet the Mother of the Internet".
IEEE Women in Engineering Magazine
.
4
(2): 10?12.
doi
:
10.1109/MWIE.2010.938214
.
S2CID
32207039
.
- ^
"College's Chamber Chorus Presents Oratorio Tuesday"
,
Red Bank Register
, December 12, 1968. Accessed September 20, 2021. "He will be accompanied by Radia Perlman, also an Ocean Township High School senior."
- ^
Leonel Morgado; et al. (2006). "Radia Perlman ? A pioneer of young children computer programming".
Current Developments in Technology-Assisted Education
: 1903?1908.
CiteSeerX
10.1.1.99.8166
.
- ^
"Radia Perlman"
.
MIT
. Archived from
the original
on December 8, 2007
. Retrieved
October 14,
2012
.
- ^
"Patents by Inventor Radia J. Perlman"
. Justia Patents
. Retrieved
August 29,
2013
.
- ^
"Radia Perlman Spanning Tree Protocol"
. mit
. Retrieved
August 29,
2013
.
- ^
"Radia Perlman | Internet Hall of Fame"
.
internethalloffame.org
. Retrieved
November 23,
2017
.
- ^
a
b
Juneau, Lucie (October 18, 1992). "Radia Perlman".
Network World
.
9
(41): 103.
ISSN
0887-7661
.
- ^
Eastlake, Donald.
"TRILL History"
.
IETF Datatracker
.
- ^
"Inter-Domain Routing Protocol"
.
ISO/IEC
.
- ^
Cisco.com.
"Open Shortest Path First"
.
- ^
"Internet Hall of Fame Pioneer Radia Perlman"
.
Internet Society
.
- ^
"2010 SIGCOM Lifetime Achievement Award given to Radia Perlman"
.
SIGCOMM
.
- ^
Fuller, Brian (October 18, 2005).
"Perlman, Samuelson, Tsao, honored for innovations"
.
EETimes
. UBM Electronics
. Retrieved
June 29,
2011
.
- ^
"Inventors of The Year"
, Silicon Valley Intellectual Property Law Association (SVIPLA). Retrieved 2 July 2013.
- ^
"IEEE Fellows 2008 | IEEE Communications Society"
.
- ^
Cacm Staff (March 2017), "ACM Recognizes New Fellows",
Communications of the ACM
,
60
(3): 23,
doi
:
10.1145/3039921
,
S2CID
31701275
.
External links
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