He left IBM to attend graduate school at the University of California, Los Angeles, where he earned his M.S. degree in 1970 and his PhD in 1972.[6][20] Cerf studied under Professor Gerald Estrin and worked in Professor Leonard Kleinrock's data packet networking group that connected the first two nodes of the ARPANET,[21] the first node[21] on the Internet, and "contributed to a host-to-host protocol" for the ARPANET.[22]
While at UCLA, Cerf met Bob Kahn, who was working on the ARPANET system architecture.[22] Cerf chaired the International Networking Working Group. He wrote the first TCP protocol with Yogen Dalal and Carl Sunshine, called Specification of Internet Transmission Control Program (RFC 675), published in December 1974.[23]
