The First Three-Network Transmission, 1977

Schematic of the 1977 demonstration event. (Click on it for a larger version.)
SRI's mobile packet radio van, from which the first three-network transmission was originated.
View photos from the November 7, 2007 anniversary event.

1977 marked a critical milestone in the development of the modern Internet and wireless networking. While many people trace the Internet's origins to the ARPANET of the late 1960s, the word "internet" means joining different kinds of individual networks together. Internetworking made its formal debut with the first connection across three dissimilar networks in 1977. SRI played a major role.

In the fall of that year, an unmarked step van filled with futuristic equipment, SRI engineers, and sometimes fully uniformed generals quietly cruised the streets of the San Francisco Bay Area. Only an oddly shaped antenna gave any hint of its purpose. A singular event occurred on November 22, when data flowed seamlessly through the van between SRI International in Menlo Park and the University of Southern California in Los Angeles via London, England, across three types of networks: Packet Radio, Satellite, and the ARPANET. Packet radio, being the first mobile digital radio, also foreshadowed WiFi and other kinds of wireless access.

In addition to the SRI van, which served as a mobile research laboratory, a broad set of technologies played an important role in the 1977 event:

Packet Radio
Built by Collins Radio Group (now Rockwell Collins)

Terminal Interface Unit and TCP Client
Built by SRI International; contains a modified Telnet terminal handler and one of the first versions of TCP, started at Stanford University and completed at SRI

Gateways
Designed and implemented by BBN for connecting the ARPANET to both the Packet Radio and Satellite Networks

TCP Server
In a Digital Equipment Corporation TENEX host located at University of Southern California's Information Sciences Institute

Packet Satellite Network
Implemented by Linkabit Corporation and others between England, Sweden, and the United States

Packet Radio Network
Designed and implemented by BBN, Collins Radio, SRI, and University of California, Los Angeles, with system integration and technical direction by SRI

ARPANET
First major packet-switched network consisting of landlines in the U.S. with overseas nodes in Norway and England

30th Anniversary Celebration

On November 7, 2007, the Computer History Museum and the Web History Center presented a special celebration of this historic demonstration that led to the Internet we know and use today. A panel presentation featured recollections and perspectives from seven computer-industry pioneers and luminaries who participated in the historical event (their affiliation at the time is listed here):

• Vint Cerf, DARPA
• Jim Garrett, Collins Radio Company
• Irwin Jacobs, Linkabit
• Bob Kahn, DARPA
• Donald Nielson, SRI International
• Paal Spilling, Norwegian Defense Research Establishment
• Virginia Strazisar Travers, BBN

Gina Smith, New York Times best-selling author of iWoz and a well-known technology and science journalist, moderated the panel.

Press coverage of the November 7, 2007 event

• How a Bread Truck Invented the Internet, The Register, November 12, 2007
• 'Internet van' helped drive evolution of the Web, ZDNet News, November 8, 2007

Read the Computer History Museum/Web History Center press release about the event.