April 22, 2011, 5:44 PM — Dr. Alexander Pasik, Chief Information Officer, IEEE, interviews Radia Perlman, IEEE Fellow and inventor of the Spanning Tree Protocol
You are an IEEE Fellow and well-known to anyone in the networking field, especially for inventing the first spanning tree protocol. What have you been working on recently?
Ironically, one of the things I've been working on these days is replacing the spanning tree with a new technology, being standardized in IETF, called "TRILL" (Transparent Interconnection of Lots of Links). While spanning tree-based Ethernet was popular because of its simplicity and ability to self-configure, it didn't make optimal use of bandwidth, and was, for subtle geeky reasons, somewhat fragile. TRILL will fix these problems, but do it in a way that is completely compatible with everything.
What advice would you give to fellow engineers?
Start out with finding the right problem to solve. This is a combination of "what customers are asking for", "what customers don't even know they want yet" and "what can be solved with something simple to understand and manage". And, try to think about and understand various approaches, and the tradeoffs between various choices.
Many network protocol designers learned the field from your books, and keep a copy on their bookshelves. What changes do you think need to be made to the way engineers and computer scientists are taught?
I get frustrated with how networking is taught in many places. Rather than approaching it as a science, students are merely told to memorize the specifications of the existing deployed devices. Instead, I believe students should be taught the concepts, such as "how would one acquire a network address without being configured", and then study a bunch of different approaches that could exist, or have existed in other protocols. I believe that understanding design tradeoffs and alternatives will be far more beneficial than memorizing the details of one protocol suite, and will enable the students to think critically, and will increase their ability to design new things.
You have transformed the technology industry several times; with the spanning tree that transformed Ethernet, with link state routing, and with TRILL. Is your love for technology what inspires your work?
Actually, I hate technology! There are some people who love gadgets, love using them, love taking them apart and tinkering with the insides. When my daughter was in high school she told her friends proudly that her mother "had a PhD from MIT and knew all about computer science". Then I'd have her friends calling me up and saying "when I try to configure a printer I get this error message." I had to explain to my daughter that, yeah, although I'm considered an expert at this esoteric thing called network protocol design, I wasn't likely to be able to help her friends at anything practical.
But the world would be a better place if more engineers, like me, hated technology.
The stuff I design, if I'm successful, nobody will ever notice. Things will just work, and be self-managing. Though, I've learned that some people like to configure things, so I usually design in knobs for them to play with, and perhaps improve things, but any setting of the knobs will still work correctly.
When engineers [who] just love this stuff design something, we wind up with a system that asks an innocent person attempting to install email, "Do you want POP or IMAP?" One common comment engineers make is that we need "more user training". That's just wrong. Instead of expecting humans to adapt to an interface slapped together by engineers, engineers should strive to create a system that is designed for humans in their natural form.
About Dr. Radia Perlman
Dr. Radia Perlman is an IEEE Fellow, a software designer and network engineer. She invented the spanning-tree protocol, which is fundamental to modern Ethernet, and scalable and robust link state routing technology that is crucial to the operation of today's Internet.
She joined Intel Corporation in spring 2010 as an Intel Fellow and is responsible for ensuring Intel Labs' leadership in network and security. Prior to her position at Intel, Dr. Perlman worked as a Fellow at Sun Microsystems. Holding more than 100 issued patents, Dr. Perlman invented many fundamental technology innovations in computer networking. In addition to inventing the spanning tree protocol and IS-IS while working for Digital Equipment Corporation, Dr. Perlman recently developed TRILL, an emerging standard for data center interconnection that can replace today's spanning tree Ethernet.
Dr. Perlman is the author of a textbook on networking and coauthor of a textbook on network security. She has been recognized with numerous industry awards including an honorary doctorate from KTH Royal Institute of Technology in Sweden, the Usenix Association lifetime achievement award, the SIGCOMM lifetime achievement award, Silicon Valley Inventor of the year and the Women of Vision Award for Innovation.
Dr. Perlman attended MIT, where she received her Ph.D. in computer science. Her thesis was the seminal work in network routing resistant to malicious failures of switches. She also developed a child-friendly version of the educational robotics language LOGO, called TORTIS (Toddler's Own Recursive Turtle Interpreter System), which helps teach young children about computer programming.
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