1 Answer


  • ARPANET stands for Advanced Research Projects Agency Network (ARPANET).
  • It was the world’s first fully operational packet switching computer network.
  • It was built to accommodate research equipment on packet switching technology and to allow resource sharing.
  • ARPANET became popular among academicians and research scholars for collaboration through electronic mail and other services.
  • It is also called a predecessor of the modern Internet.
  • Because many of the protocols used by computer networks today were developed for ARPANET.
  • Such as the TCP/IP reference model was used earlier by ARPANET, before being used on the Internet.
  • Therefore, it is considered the forerunner of the modern internet.
  • Before ARPANET, the networks were the telephone networks that operated on the circuit switching principle.
  • But this circuit-switched network was too vulnerable, the loss of even one line or switch would terminate all the conversations.
  • To overcome this problem ARPANET was built with the concept of a packet switching network consisting of the subnet and host computers.
  • The subnet was a datagram subnet and each subnet consists of mini-computers called Interface Message Processors (IMPs).
  • Each node of the network used to have an IMP and a host connected by a short wire
  • The host could send messages of up to 8063 bits to its IMP which would break them into packets and forward them independently toward the destination.
  • The subnet was the first electronic store-and-forward type packet-switched network.
  • So each packet was stored before it was forwarded.
  • Therefore, the software for ARPANET was split into two parts namely subnet and host.
  • The TCP/IP model and protocol were invented specifically to handle communication over internetwork because more and more networks were getting connected to ARPANET.
  • ARPANET is considered a version of WAN.
  • In 1983 the management of ARPANET was handed over to the Defense Communications Agency (DCA) which separated the military portion into a separate MILNET.
  • By 1990 the ARPANET was shut down and dismantled, however, MILNET continues to operate.

Benefits of ARPANET:

  • ARPANET was first built to service even in a Nuclear Attack by the US.
  • It allows collaborations through Emails.
  • It improves the process of transfer of files and data of defense.

Limitations of ARPANET:

  • Increased number of LAN connections resulted in difficulty handling.
  • It was unable to cope-up with advancements in technology.


  • DARPANET meaning is Defense ARPANET.
  • The United States government network merged with the ARPANET to form the DARPA Internet.
  • This was during the height of the Cold War.
  • The U.S. military was interested in creating computer networks that could continue to function after having portions removed, such as in the case of a nuclear strike.
  • This eventually gave rise to the Internet.
  • In 1972, the name of the department changed to the Defense Advanced Research Projects Agency (DARPA), and so many assume that the name of the network also changed to DARPANET.
Please log in to add an answer.