Leonard Bosack facts for kids

Leonard X. Bosack was born in 1952. He is famous for being a co-founder of Cisco Systems. Cisco is a big company that creates and sells technology for computers and networks.

Leonard Bosack helped make it possible for computers in different places to connect. He used a special system called a router. This was a new idea at the time. In 2009, he received the Computer Entrepreneur Award. This award recognized his work in starting Cisco and making routing technology popular. In 1990, he left Cisco. As of 2025, Bosack is the CEO of XKL LLC. This company works on new ways to send data using light.

Early Life and Education

Leonard Bosack was born in Pennsylvania in 1952. He went to La Salle College High School and finished in 1969. In 1973, he graduated from the University of Pennsylvania School of Engineering and Applied Science. After that, he worked as an engineer at Digital Equipment Corporation (DEC).

In 1979, he started studying computer science at Stanford University. While at Stanford, he helped connect all the university's computers. He worked on a special network router. This router allowed computers in different labs to share information. At Stanford, he met Sandra Lerner, who managed a computer lab. They got married in 1980. In 1984, they started Cisco together.

Starting Cisco Systems

In 1984, Leonard Bosack and his then-wife, Sandy Lerner, started Cisco Systems. Their goal was to sell a special computer device called the Advanced Gateway Server. This device was an improved version of a router built at Stanford. Bosack and Lerner built these routers in their home. They also tested them using Stanford's computer network.

They first asked Stanford if the university wanted to sell the routers. When Stanford said no, they decided to start their own company. They named it "Cisco," which came from the name of nearby San Francisco. It's a common story that they built the first router to send messages between their different offices at Stanford. However, this story is not true.

Cisco's first product was developed in their garage. They started selling it in 1986, mostly by word of mouth. In their first month, Cisco earned over $200,000 in contracts. The company created new technology, like special cards for routers and advanced routing protocols. This helped them become leaders in the market. Cisco became a public company in 1990. That same year, Bosack left the company. Bosack and Lerner received $170 million when they left Cisco. They divorced a few years later.

By 1996, Cisco's sales reached $5.4 billion. It became one of the biggest success stories in Silicon Valley. By 1998, the company was worth over $6 billion. It controlled more than three-quarters of the router business.

Key Achievements and Contributions

Besides co-founding Cisco Systems, Leonard Bosack helped make local area network (LAN) technology popular. He and his team at Stanford successfully connected 5,000 computers across a 16 square kilometer campus. This was a big deal because LAN technology was very new at the time. Their challenge was to make different computers work together. They created the first true LAN system.

Bosack also held important technical jobs at AT&T Bell Labs and Digital Equipment Corporation. After getting his master's degree from Stanford University, he became the Director of Computer Facilities for Stanford's Computer Science Department. He was also a key person in the early development of ARPAnet. ARPAnet was the beginning of what we now call the Internet.

More recently, Bosack has created new systems for fiber optic cables. These systems can send data incredibly fast. For example, they can send data over 1231 kilometers (about the distance between Chicago and New York City) in just 6.071 milliseconds. Bosack believes that by using the natural physics of fiber optic parts, data can be sent faster. His devices also use less power, take up less space, and need less cooling.

Charitable Work

Leonard Bosack and Sandy Lerner have a foundation that helps others. They funded it with 70% of the money they made from selling their Cisco stock. This foundation supports many projects. It helps with animal welfare and science research. For example, it has helped The Center for Conservation Biology at the University of Washington. The foundation also bought an old English manor house called Chawton House. This house used to belong to Jane Austen's brother. Now, it is a research center for women writers from the 18th and 19th centuries.