Stephen D Crocker ("Steve") was the leader of the Network Working Group that developed the Network Control Protocol (NCP). I was part of that team but Steve deserves the credit for leading it. It was experience with the NCP on the ARPANET and the differences between ARPANET and the less reliable Packet Radio and Packet Satellite networks that led Bob Kahn and me to conclude that we needed additional functionality at the TCP layer. One the third iteration of the TCP design, Danny Cohen, Jon Postel and David Reed argued successfully to split IP from TCP so as to support unsequenced, real-time delivery. This led to UDP and the notions of streaming audio and video and other real-time streams.

Vint Cerf’s Facebook profile includes a picture of him wearing his favorite t-shirt: it reads “IP on Everything.”