ARPANET (Advanced Research Projects Agency Network)

ARPANET was the first operational packet-switching network and a precursor to the modern Internet. It was developed in 1969 by the United States Department of Defense’s Advanced Research Projects Agency (ARPA) to enable secure and reliable communication between research institutions.

The initial ARPANET connected four university computers:

  1. University of California, Los Angeles (UCLA)
  2. Stanford Research Institute (SRI)
  3. University of California, Santa Barbara (UCSB)
  4. University of Utah

ARPANET introduced the concept of packet switching, which allowed data to be broken into packets, transmitted independently, and reassembled at the destination — a foundational principle still used in networking today.

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