Some background: new leadership at ARPANET demanded all hosts to switch from the old protocol (NCP) to the new one developed by Cerf and Kahn (TCP). This change caught many by surprise, and the migration was a long and painful one for teams. "The transition from NCP to TCP was done in a great rush...occupying virtually everyone's time 100% in the year 1982. Nobody was ready" (Janet Abbate, Inventing the Internet, MIT Press 1999)