As a graduate student at the University of California Los Angeles (UCLA) in the 1960s, he was part of the team that developed the protocols for the ARPANET which were the foundation for today's Internet.[5] He said "While much of the development proceeded according to a grand plan, the design of the protocols and the creation of the RFCs was largely accidental."[nb 1] He was instrumental in forming a Network Working Group (NWG) in 1969 and was the instigator of the Request for Comment (RFC) series,[6] authoring the first RFC[7] and many more.[8] Crocker led other graduate students, including Jon Postel and Vint Cerf, in designing a host-host protocol known as the Network Control Program (NCP).[nb 2] They planned to use separate protocols, Telnet and the File Transfer Protocol (FTP), to run functions across the ARPANET.[nb 3][9][10] NCP codified the ARPANET network interface, making it easier to establish, and enabling more sites to join the network.[11][12]
While at UCLA Crocker taught an extension course on computer programming (for the IBM 7094mainframe computer). The class was intended to teach digital processing and assembly language programming to high school teachers, so that they could offer such courses in their high schools. A number of high school students were also admitted to the course, to ensure that they would be able to understand this new discipline. Crocker was also active in the newly formed UCLA Computer Club.
The Networking Working Group RFC's provided the context in which the IETF was created in 1986. He has been an IETF security area director, a member of the Internet Architecture Board, chair of the ICANN Security and Stability Advisory Committee, board member and chairman of ICANN, a board member of the Internet Society and numerous other Internet-related volunteer positions.
^RFCs began as informal technical notes, "requests for comments", of the Networking Working Group (NWG).
^Crocker said "NCP" later came to be used as the name for the protocol, but it originally meant the program within the operating system that managed connections. The protocol itself was known blandly only as the host-host protocol.'
^The NPL network team also envisaged the need for levels of data transmission in 1968. Both were early examples of the protocol layering concept incorporated in the OSI model.
^Cerf, V.; Kahn, R. (1974). "A Protocol for Packet Network Intercommunication"(PDF). IEEE Transactions on Communications. 22 (5): 637–648. doi:10.1109/TCOM.1974.1092259. ISSN1558-0857. The authors wish to thank a number of colleagues for helpful comments during early discussions of international network protocols, especially R. Metcalfe, R. Scantlebury, D. Walden, and H. Zimmerman; D. Davies and L. Pouzin who constructively commented on the fragmentation and accounting issues; and S. Crocker who commented on the creation and destruction of associations.