 Robert E. Kahn of DARPA and ARPANET recruited Vinton Cerf of Stanford University to work with him on the problem.By 1973, they had worked out a fundamental reformulation, where the differences between network protocols were hidden by using a common internetwork protocol, and instead of the network being responsible for reliability, as in the ARPANET, the hosts became responsible.Cerf credits Hubert Zimmermann and Louis Pouzin (designer of the CYCLADES network), and his graduate students Judy Estrin, Richard Karp, Yogen Dalal and Carl Sunshine with important work on this design.