radia perlman radia joy perlman born 1951 is an american computer programmer and network engineer she is most famous for her invention of the spanningtree protocol stp which is fundamental to the operation of network bridges while working for digital equipment corporation she also made large contributions to many other areas of network design and standardization such as linkstate routing protocols more recently she has invented the trill protocol to correct some of the shortcomings of spanningtrees she is currently employed by dell emc early life perlman grew up near asbury park new jersey 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 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 handson type person it never occurred to me to take anything apart i assumed id either get electrocuted or id break something education as an undergraduate at mit perlman learned programming for a physics class she was given her first paid job in 1971 as parttime programmer for the logo lab at the then mit artificial intelligence laboratory programming system software such as debuggers working under the supervision of seymour papert she developed a childfriendly version of the educational robotics language logo called tortis toddlers own recursive turtle interpreter system during research performed in 197476 young childrenthe youngest aged 3 years programmed a logo educational robot called a turtle perlman has been described as a pioneer of teaching young children computer programming 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 when studying at mit in the late 60s she was one among the 50 or so women students in a class of about 1000 students to begin with mit only had one womens dorm limiting the number of women students that could study when the mens dorms at mit became coed perlman moved out of the womens 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 career 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 perlman is the author of a textbook on networking and coauthor of another on network security she holds more than 100 issued patents spanning tree protocol perlman invented the spanning tree algorithm and the spanning tree protocol stp while working as a consulting engineer at the digital equipment corporation dec in 1984 she was tasked with developing a straightforward protocol which 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 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 not reach their destination flooding the network perlman utilised 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 perlmans concerns that it took the spanning tree protocol about a minute to react when changes in the network topology occurred in which time a loop could bring down the network it was standardised as 8021d by the institute of electrical and electronics engineers ieee perlman said that the benefits of the protocol amount to the fact that you dont have to worry about topology when changing the way a lan is interconnected perlman has however criticised that changes were made in the course of the standardisation of the protocol from the paper an algorithm for distributed computation of a spanning tree in an extended lan algorhyme i think that i shall never see a graph more lovely than a tree a tree whose crucial property is loopfree 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 perlman was the principal designer of the decnet iv and v protocols which are part of the decnet network protocol suite for peertopeer network architectures 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 open system interconnection routing protocol idrp which allows routers in packet switching networks to communicate with one another across broadcast domains at dec she also oversaw the transition from distance vector to linkstate routing protocols linkstate routing protocols had the advantage that they adapted to changes in the network topology faster and decs linkstate routing protocol was second only to the linkstate routing protocol of the advanced research projects agency network arpanet while working on the decnet project perlman also helped to improve the intermediatesystem to intermediatesystem routing protocol known as isis so that it could route the internet protocol ip appletalk and the internetwork packet exchange ipx protocol the open shortest path first ospf protocol relied in part on perlmans research on faulttolerant broadcasting of routing information perlman subsequently worked as network engineer for sun microsystems now oracle she specialised on network and security protocols and while working for oracle obtained more than 50 patents awards national inventors hall of fame induction 2016 internet hall of fame induction 2014 sigcomm award 2010 usenix lifetime achievement award 2006 recipient of the first anita borg institute women of vision award for innovation in 2005 silicon valley intellectual property law association inventor of the year 2003 honorary doctorate royal institute of technology june 28 2000 twice named as one of the 20 most influential people in the industry by data communications magazine in the 20th anniversary issue january 15 1992 and the 25th anniversary issue january 15 1997 perlman is the only person to be named in both issues fellow of the association for computing machinery class of 2016 bibliography perlman radia 1999 interconnections bridges routers switches and internetworking protocols 2 ed addisonwesley professional computing series isbn9780201634488 perlman radia kaufman charlie speciner mike 2002 network security private communication in a public world 2 ed ptr prentice hall isbn9780130460196 wikimedia commons has media related to radia perlman inventor of the week archive at mit spanning tree algorithm vteinternet hall of famepioneers2012 paul baran vint cerf danny cohen steve crocker donald davies elizabeth j feinler charles herzfeld robert kahn peter t kirstein leonard kleinrock john klensin jon postel louis pouzin lawrence roberts 2013 david clark david farber howard frank kanchana kanchanasut j c r licklider bob metcalfe jun murai kees neggers nii quaynor glenn ricart robert taylor stephen wolff werner zorn 2014 douglas engelbart susan estrada frank heart dennis jennings rolf nordhagen radia perlman global connectors2012 randy bush kilnam chon al gore nancy hafkin geoff huston brewster kahle daniel karrenberg toru takahashi tan tin wee 2013 karen banks gihan dias anriette esterhuysen steve goldstein teus hagen ida holz qiheng hu haruhisa ishida barry leiner george sadowsky 2014 dai davies demi getschko masaki hirabaru erik huizer steve huter abhaya induruwa dorcas muthoni mahabir pun srinivasan ramani michael roberts ben segal douglas van houweling 2017 nabil bukhalid ira fuchs shigeki goto mike jensen ermanno pietrosemoli tadao takahashi florencio utreras jianping wu innovators2012 mitchell baker tim bernerslee robert cailliau van jacobson lawrence landweber paul mockapetris craig newmark ray tomlinson linus torvalds phil zimmermann 2013 marc andreessen john perry barlow francois fluckiger stephen kent annemarie eklund lwinder henning schulzrinne richard stallman aaron swartz jimmy wales 2014 eric allman eric bina karlheinz brandenburg john cioffi hualin qian paul vixie 2017 jaap akkerhuis yvonne marie andres alan emtage ed krol tracy laquey parker craig partridge authority control worldcat identities acm dl 81100008303 bne xx5405959 bnf cb124400913 data dblp 872370 gnd 172561426 isni 0000 0001 1596 6252 lccn n91097789 mgp 86235 ndl 00515489 snac w6rd2gp9 sudoc 033543364 viaf 12400871 