Undergoing constant research and development in the early-to mid-1970s,ARPAnet served as the test bed for the development of TCP/IP( the protocols that make the Internet possible ).

• ARPA网作为开发TCP/IP(一种使互连网成为可能的协议)的试验台,在70年代的早期到中期就进行了不断的研究和开发。