Internetworking: The First Three-Network Transmission

The word "Internet" refers to different kinds of networks joined together. Many people trace the Internet's origins to the ARPANET of the late 1960s, but that was just a single, closed network. Internetworking made its formal debut in 1977 with the first connection across three dissimilar networks. SRI played a major role in this critical milestone in the development of the modern Internet and wireless networking.

On November 22 of that year, the antenna of an SRI van cruising the streets of the San Francisco Bay Area transmitted data between SRI International in Menlo Park and the University of Southern California (USC) in Los Angeles via London, England, across three types of networks: packet radio, satellite, and the ARPANET. Packet radio — the first mobile digital radio — foreshadowed Wi-Fi and other kinds of wireless technology.

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

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

Terminal Interface Unit and TCP Client
Built by SRI; 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 the packet radio and to satellite networks

TCP Server
In a Digital Equipment Corporation TENEX host located at USC's Information Sciences Institute

Packet Satellite Network
Network between England, Sweden, and the U.S.; implemented by Linkabit and others

Packet Radio Network
Designed and implemented by BBN, Collins Radio, SRI, and the 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 celebrated the historic demonstration that led to the Internet we know and use today. A panel presentation moderated by Gina Smith, The New York Times best-selling author of iWoz and a well-known technology and science journalist, featured the recollections and perspectives of seven computer industry pioneers and luminaries who participated in the historic event. Their names and affiliations at that time include:

• Vint Cerf, Defense Advanced Research Projects Agency (DARPA)
• Jim Garrett, Collins Radio
• Irwin Jacobs, Linkabit
• Bob Kahn, DARPA
• Donald Nielson, SRI
• Paal Spilling, Norwegian Defense Research Establishment
• Virginia Strazisar Travers, BBN