Judy Estrin: Networking Entrepreneur

But things didn't turn out quite as expected.

Estrin decided to leave college after earning a master's degree and later went on to launch four successful Silicon Valley companies, becoming an architect of modern networking technology,in areas including networking hardware, network-based computing, thin clients and multimedia,and, along with her husband Bill Carrico, one of the high-tech industry's most prominent entrepreneurs.

Estrin and Carrico started Bridge Communications, Network Computing Devices (NCD) and Precept Software. They currently run Packet Design, a Mountain View, Calif.-based company that develops Internet infrastructure technology.

Estrin's entrepreneurial spirit wasn't evident early on, however. As a child, she displayed a talent for math, and her parents hoped she would seek a career in academia, said her mother, Thelma.

"We would have loved for her to follow in our footsteps and get her Ph.D.," she said. "But it was clear after her first job that she had a strong interest in the business side of technology."

At age 12, Estrin met networking guru Vint Cerf, one of the founding fathers of the Internet, through her father, Gerry, who was Cerf's thesis adviser. Later, while studying for her master's degree in electrical/computer engineering at Stanford University, Estrin worked in Cerf's lab at the college as part of the team that developed the TCP/IP protocols.

"Judy is a very good engineer," said Cerf, who is now senior vice president of Internet architecture and technology at WorldCom, Clinton, Miss. "But she has been able to translate technical concepts and ideas into practical business models."

After finishing her master's at Stanford, Estrin took a job at semiconductor firm Zilog. It was there that she realized her interest in business.

"I think my parents are pretty proud of me and what I've accomplished," said Estrin, who turns 47 this month. "But it was a surprise to all of us that I ended up going into business."

Because Zilog was a small company, Estrin,then an engineer,was exposed to customers and their needs. "That's where I learned that I wasn't interested in technology for technology's sake but in technology as applied to solving problems," she said.

Zilog also was where Estrin met Carrico, now 51, who also played a role in her career shift. "Bill gave me exposure to the business aspect and was my mentor in the early stages of my career and then became my partner and husband," she said.

At a time when Silicon Valley was a man's world, Estrin and Carrico began their entrepreneurial partnership, starting router company Bridge Communications in 1981, three years before Cisco Systems surfaced. Bridge was highly successful, and Estrin and Carrico took the company public in 1985. In 1987, Bridge merged with 3Com in a $235 million deal.

Estrin and Carrico had planned to stay with 3Com, "but in mergers, things don't often happen the way you think they will," she said. "So we ended up leaving."

That led the couple to their next venture, Unix terminal vendor Network Computing Devices, which went public in 1992. In 1994, when NCD approached $140 million in sales, Estrin and Carrico left to take some time off,but not for long.

In 1995, they launched Precept Software, which developed Internet video technology. Precept was sold to Cisco in 1998 for about $84 million in stock, and under the deal, Estrin became CTO at Cisco, where she stayed for two years.

Though Estrin said her Cisco experience was valuable, her action-oriented personality made her itch to become more involved in company operations.

"I contributed a lot and got a lot out of it, but it was really hard to go from running your own show to a CTO where, as opposed to getting things done, you manage through influence," she said. "One of the reasons I like start-ups is because I like both breadth and scope. But I also like diving into the details. At a large company, if you want the breadth and to make the decisions, you can't possibly dive in deep because there's too much going on."

During her stint at Cisco, Estrin and Carrico formulated the idea for their fourth start-up, Packet Design, which was founded in April 2000. Estrin and Cisco Chief Scientist Van Jacobson had often discussed the state of the Internet and what they began to call its "architectural vacuum," she said.

"The market had been growing so fast that much of the industry was focused on putting Band-Aids on problems as opposed to looking at what the underlying scalability issues were with the Internet and where we needed to take it," Estrin said.

With a mission to focus on long-term solutions for the Internet, Estrin sowed the seeds for Packet Design, a venture that she and her husband decided to take a different route.

"We didn't want to start another product company in April 2000 because we knew we were at the peak of the stock market bubble," she said. "And we didn't want to start a company that another company would acquire in a couple of years."

Launched with $24 million in funding from backers including Foundation Capital, former Netscape CEO Jim Barksdale and Sun Microsystems Chief Scientist Bill Joy, Packet Design was formed with the goal of remaining a small, private company focused on developing technology rather than selling product. Calling Packet Design a "perpetual start-up," Estrin said the company's aim is to spin off product companies once solutions are developed or to license technology to other vendors.

Packet Design in some cases may sell technology directly to service providers to develop a market and get customer feedback, but the company will never sell products in high volume, said Estrin.

Though declining to specify what Packet Design is working on, Estrin did reveal a few areas of focus for the company.

"The basic architecture of IP and the Internet is the right one, but we're starting to run up against some limitations of the current routing technology," she said. "Whether it's because of the convergence of voice and data or the sheer size and the number of connections, we need some changes to the current routing technology."

Security and mobility for wireless LANs is another area Packet Design focused on in its first year. The result: the company's first spin-off, Vernier Networks, which recently launched a Layer 3-based solution that allows network managers to control access and use of their wireless LANs at the user level, said Vernier CEO Doug Klein. Current 802.11b solutions are based on Layer 2 technology, which doesn't enable access control at the user level, he said. Vernier's user-based authentication and access control also lets network managers assign specific rights to each user.

"Like we did with Vernier, we're working on technology that takes the current infrastructure and makes it better," Estrin said.

With three successful start-ups under her belt and significant wealth, Estrin could have kicked back, relaxed and watched from the sidelines instead of starting another company. But that wasn't in her nature, she said.

"Lots of people ask me why I don't retire. The answer is simple: I enjoy doing this. I am passionate about the technology. I enjoy building things, building teams and leading people. Clearly, at this point I do this because it gives me satisfaction and not because I'm building a career or need to do it financially," Estrin said. "What do you do when you retire? You do what you like to do. So I'm doing what I like to do."

Gerry Estrin describes his daughter as a "remarkably powerful woman and a wonderful leader" with the ability to work with people and products and to anticipate trends. "She has built companies at the forefront of the technology," he said.

Cerf agreed. "Judy has become a very successful businesswoman, but she hasn't changed a great deal," he said. "She's still very straightforward, and she's not afraid to raise an issue or ask the tough questions."

Her training for the tough questions probably came at the dinner table in the Estrin household, said Cerf. In a dining room filled with books, the Estrin family always had vigorous debates at the dinner table, he recalled.

"Nary an evening would go by without someone cracking a book and starting a discussion," Cerf said.

Estrin's willingness to voice her opinions reflects her leadership style, said Klein, who met her in 1988 as a co-founder of NCD and later worked with her at Packet Design prior to becoming president of Vernier.

"[Estrin is] very straightforward,no politics and no B.S.," Klein said. "She is very concerned that you're working to solve the right problem. She will listen to you, but there will be heated debates. And she's never reluctant to remind you that it's not a democracy."

And despite her family's history of debating, Estrin didn't challenge Klein's description of her leadership style.

"I expect a lot from the people who work for me," she said. "I have strong opinions. I am not hands-off; I'm very involved. I also really care about the people who work for me."