<P> In March 1970, the ARPANET reached the East Coast of the United States, when an IMP at BBN in Cambridge, Massachusetts was connected to the network . Thereafter, the ARPANET grew: 9 IMPs by June 1970 and 13 IMPs by December 1970, then 18 by September 1971 (when the network included 23 university and government hosts); 29 IMPs by August 1972, and 40 by September 1973 . By June 1974, there were 46 IMPs, and in July 1975, the network numbered 57 IMPs . By 1981, the number was 213 host computers, with another host connecting approximately every twenty days . </P> <P> In 1973 a transatlantic satellite link connected the Norwegian Seismic Array (NORSAR) to the ARPANET, making Norway the first country outside the US to be connected to the network . At about the same time a terrestrial circuit added a London IMP . </P> <P> In 1975, the ARPANET was declared "operational". The Defense Communications Agency took control since ARPA was intended to fund advanced research . </P> <P> In September 1984 work was completed on restructuring the ARPANET giving U.S. military sites their own Military Network (MILNET) for unclassified defense department communications . Controlled gateways connected the two networks . The combination was called the Defense Data Network (DDN). Separating the civil and military networks reduced the 113 - node ARPANET by 68 nodes . The MILNET later became the NIPRNet . </P>

What was the major question that arpanet wanted to solve