 The Internet as we know it today was still in its infancy in the 1970s, and was mainly operated on telephone lines owned by AT&T which were leased by ARPA.At the time, AT&T did not take seriously the threat posed by packet switching; it actually turned down the opportunity to take over ARPANET.Other computer networks at the time were not really decentralized; for example, the private network Tymnet had central control computers called supervisors which controlled each other in an automatically determined hierarchy.