Lawrence Roberts (scientist)

Lawrence Gilman Roberts (December 21, 1937 – December 26, 2018) was an American engineer who received the Draper Prize in 2001 "for the development of the Internet", and the Principe de Asturias Award in 2002.
As a program manager and later office director at the Advanced Research Projects Agency, Roberts and his team created the ARPANET using packet switching techniques invented by British computer scientist Donald Davies and American Paul Baran. The ARPANET, which was built by the Massachusetts-based company Bolt Beranek and Newman (BBN), was a predecessor to the modern Internet. He asked Leonard Kleinrock to apply mathematical models to simulate the performance of the network. Roberts later served as CEO of the commercial packet-switching network Telenet. 
Early life and education.
Roberts, who was known as Larry, was born and raised in Westport, Connecticut. He was the son of Elizabeth (Gilman) and Elliott John Roberts, both of whom had doctorates in chemistry. It is said that during his youth, he built a Tesla coil, assembled a television, and designed a telephone network built from transistors for his parents' Girl Scout camp.
Roberts attended the Massachusetts Institute of Technology (MIT), where he received his bachelor's degree (1959), master's degree (1960), and Ph.D. (1963), all in electrical engineering. His Ph.D. thesis "Machine Perception of Three-Dimensional Solids" is considered as one of the foundational works of the field of Computer Vision.
Career.
MIT.
After receiving his PhD, Roberts continued to work at the MIT Lincoln Laboratory. Having read the seminal 1961 paper of the "Intergalactic Computer Network" by J. C. R. Licklider, Roberts developed a research interest in time-sharing using computer networks.
ARPA.
In 1967, although at first reluctant, he was recruited by Robert Taylor in the ARPA Information Processing Techniques Office (IPTO) to become the program manager for the ARPANET. He asked Frank Westervelt to explore the initial design questions for a network. Roberts prepared a proposal that all host computers would connect to one another directly. Taylor and Wesley Clark disagreed with this design and Clark suggested the use of dedicated computers to create a message switching network, which were later called Interface Message Processors. 
At the Symposium on Operating System Principles that year, Roberts presented the plan based on Clark's message switching proposal. There he met a member of Donald Davies's team (Roger Scantlebury) who presented their research on packet switching and suggested it for use in the ARPANET. Roberts applied Davies's concepts of packet switching for the ARPANET, and sought input from Paul Baran. 
Roberts' plan for the ARPANET was the first wide area packet-switching network with distributed control, similar to Donald Davies' 1965 design. ARPA issued a request for quotation (RFQ) to build the system, which was awarded to Bolt, Beranek and Newman (BBN). Significant aspects of the networks's operation including routing, flow control, software design and network control were developed by the BBN IMP team. Roberts managed its implementation and contracted with Leonard Kleinrock in 1968 to carry out mathematical modelling of the packet-switched network's performance. Roberts engaged Howard Frank to consult on the topological design of the network. Frank made recommendations to increase throughput and reduce costs in a scaled-up network. When Robert Taylor was sent to Vietnam in 1969 and then resigned, Roberts became director of the IPTO. 
In 1970, he proposed to NPL's Donald Davies that the two organizations connect their networks via a satellite link. This original proposal proved infeasible, but in 1971 Peter Kirstein agreed to connect his research group at University College London (UCL) instead, which was later interconnected with the NPL network. Roberts proposed in 1973 that it would be possible to use a satellite's 64 kilobit/second link as a medium shared by multiple satellite earth stations within the beam's footprint. This was implemented later by Bob Kahn, and resulted in SATNET. 
The Purdy Polynomial hash algorithm was developed for the ARPANET to protect passwords in 1971 at the request of Roberts.
Roberts approached AT&T in the early 1970s about taking over the ARPANET to offer a public packet switched service but they declined.
Telenet.
In 1973, Roberts left ARPA to join BBN's effort to commercialize the nascent packet-switching technology in the form of Telenet, the first FCC-licensed public data network in the United States. He served as its CEO from 1973 to 1980. Roberts joined the international effort to standardize a protocol for packet switching based on virtual circuits shortly before it was finalized. Telenet converted to the X.25 protocol, which was adopted by PTTs across North America and Europe for public data networks in the mid-late 1970s. Roberts promoted this approach over the datagram approach in TCP/IP being pursued by ARPA, which he described as "oversold" in 1978. 
Later career.
In 1983 he joined DHL Corporation as President. At the time, he predicted bandwidths would go down driven by voice compression technology.
He was CEO of NetExpress, an Asynchronous Transfer Mode (ATM) equipment company, from 1983 to 1993. Roberts was president of ATM Systems from 1993 to 1998. He was chairman and CTO of Caspian Networks, but left in early 2004; Caspian ceased operation in late 2006.
, Roberts was the founder and chairman of Anagran Inc. Anagran continues work in the same area as Caspian: IP flow management with improved quality of service for the Internet.
Since September 2012, he was CEO of Netmax in Redwood City, California.
Personal life.
Roberts married and divorced four times. At the time of his death, his partner was physician Tedde Rinker. Roberts died at his California home from a heart attack on December 26, 2018.