<P> In 1975, BBN introduced IMP software running on the Pluribus multi-processor . These appeared in a few sites . In 1981, BBN introduced IMP software running on its own C / 30 processor product . </P> <P> In 1983, TCP / IP protocols replaced NCP as the ARPANET's principal protocol, and the ARPANET then became one subnet of the early Internet . </P> <P> The original IMPs and TIPs were phased out as the ARPANET was shut down after the introduction of the NSFNet, but some IMPs remained in service as late as July 1990 . </P> <P> The ARPANET Completion Report, jointly published by BBN and ARPA, concludes that: </P>

The darpanet or arpanet hardware is still in place today