Systems

ARPANET

AR-puh-net

Also Known As Advanced Research Projects Agency Network

Citation Formats

General Reference

Computing Atlas. "ARPANET." Accessed August 30, 2026. https://computing.interactiveatlas.org/systems/arpanet.

APA Style

Computing Atlas. (n.d.). ARPANET. Retrieved August 30, 2026, from https://computing.interactiveatlas.org/systems/arpanet

BibTeX

@misc{computingatlas-arpanet,
  author = {Computing Atlas},
  title = {ARPANET},
  year = {2026},
  url = {https://computing.interactiveatlas.org/systems/arpanet},
  note = {Accessed August 30, 2026}
}

ARPANET, the Advanced Research Projects Agency Network, was an experimental computer network funded by the US Department of Defense, whose first node went live at UCLA in 1969, connecting four university research sites by the end of that year. It was the first network to use packet switching, breaking messages into independently routed pieces, at wide scale, and the protocols and lessons learned running it directly shaped the design of the modern internet that eventually replaced it.

Facts

Year

1969 1

Significance

The first large scale packet switched network, and the direct ancestor of the modern internet. 1

Cross-Tradition Connections

Associated With

Client-Server Model

Source Wikipedia: Client-server model

Distributed Computing

Source Wikipedia: Distributed Computing

Packet Switching

Davies's packet switching concepts and designs were incorporated into the ARPANET.

Source Wikipedia: Packet Switching

Robert Kahn

Robert Kahn worked at Bolt Beranek and Newman on the Interface Message Processor subnetwork that connected ARPANET's early nodes, before his later work with Vint Cerf on TCP/IP.

Source Wikipedia: Robert Kahn

TCP/IP

The ARPANET migrated from NCP to TCP/IP, completed on the 1 January 1983 flag day.

Source Wikipedia: Internet Protocol Suite

In Field

Computer Networking

Source Computer History Museum

Predecessor Of

The Internet

Source Computer History Museum

Sources

1. Computer History Museum

Computer History MuseumView the Source

Wikipedia: ARPANET

Wikimedia FoundationLead section

Quote, Lead section

The Advanced Research Projects Agency Network (ARPANET) was the first wide-area packet-switched network with distributed control and one of the first computer networks to implement the TCP/IP protocol suite.

View the Source

Wikipedia: Packet Switching

Wikimedia FoundationAssociated With: Packet Switching, History section

Quote, Associated With: Packet Switching, History section

Immediately after SOSP, he [Roberts] incorporated Davies' concepts and designs for packet switching to enable the data communications on the network.

View the Source

Wikipedia: Internet Protocol Suite

Wikimedia FoundationAssociated With: TCP/IP, Adoption section

Quote, Associated With: TCP/IP, Adoption section

The migration of the ARPANET from NCP to TCP/IP was officially completed on flag day January 1, 1983, when the new protocols were permanently activated.

View the Source

Wikipedia: Robert Kahn

Wikimedia FoundationAssociated With: Robert KahnView the Source

Wikipedia: Client-server model

Wikimedia FoundationAssociated With: Client-Server Model, History section

Quote, Associated With: Client-Server Model, History section