SATNET, also known as the Atlantic Packet Satellite Network, was an early satellite network that formed an initial segment of the Internet. It was implemented by BBN Technologies under the direction of ARPA.
The first heterogeneous computer network was implemented in 1973, connecting the ARPANET to University College London. This evolved into SATNET. The first Transmission Control Program demonstration, linking SATNET, the ARPANET, and PRNET took place on November 22, 1977.
SATNET had its origins in Larry Roberts' 1970 proposal for a link between the ARPANET and the National Physical Laboratory (NPL) network. The NPL network was developed by Donald Davies, one of two independent inventors of the concept of packet switching. ARPA had an existing 2.4 kilobit/second link to NORSAR (used for seismic research), which at the time passed through a satellite station in the UK, then continued via cable to Norway. [1]
Peter T. Kirstein's research group at University College London (UCL) was chosen instead of NPL in 1971 to connect the ARPANET. Funding was finally approved in 1973, by which time the trans-Atlantic connectivity had changed: the NORSAR link now crossed the Atlantic via the Nordic satellite station in Tanum, Sweden, then continued via cable to Norway. [2] Two ARPANET Terminal Interface Processors (TIPs) were installed in Norway and connected to the ARPANET via satellite in June and September 1973. The UCL connection via a terrestrial circuit to Norway became operational in July 1973 at 9.6 kilobits/second. At this point, UCL was connected to the ARPANET, forming the first heterogeneous interconnected network in the world. UCL later provided a gateway for an interconnection with the SRCnet, the forerunner of the UK's JANET network. [1]
In that same year, Larry Roberts proposed that it would be possible to use a satellite's 64 kilobit/second link as a medium shared by multiple satellite earth stations within the beam's footprint.
This proposal was implemented by Bob Kahn, and resulted in SATNET. Key participants in SATNET included BBN Technologies, COMSAT, the Linkabit Corporation, [3] UCLA, University College London, the Norwegian Defence Research Establishment and the Royal Signals and Radar Establishment in Britain. By the late 1970s, SATNET connected research sites in the US, UK, Norway, Germany, and Italy. [4]
In 1973, Bob Kahn considered the interconnection of the ARPANET with other networks. He enlisted Vint Cerf, who was teaching at Stanford. The problem was that the ARPANET, SATNET, and radio-based PRNET all had different interfaces, packet sizes, labelling, conventions and transmission rates. Linking them together was very difficult. In response, Kahn and Cerf set about designing a net-to-net connection protocol. Cerf led the newly formed International Network Working Group (INWG). In September 1973, the two gave their first paper on the new Transmission Control Program at an INWG meeting at the University of Sussex in England. Their proposal, published the next year, incorporated concepts developed by Louis Pouzin and Hubert Zimmermann, designers of the CYCLADES network. [5] [6]
The first Transmission Control Program demonstration, linking SATNET, the ARPANET, and PRNET took place on November 22, 1977. As a result of this work, SATNET played a central role in the creation of the Internet protocol suite.
Peter Kirstein chaired the International Cooperation Board (ICB), formed by Cerf in 1979, to coordinate activities to develop packet satellite research. [7] [8]
SATNET was assigned the 4.x.x.x/8 IPv4 address range in the List of assigned /8 IPv4 address blocks.
In later years, J. C. R. Licklider remembered the difficulty in arranging such satellite links during his second ARPA tour: [9]
When I was [at ARPA in 1974-1975], we were trying to set up a satellite link with Britain, and to deal with British General Post Office, or whatever that's called, was just a totally different experience to me from anything else. They wanted us to buy insurance covering their whole plant, practically, in case our IMPs set fire, or something, to their equipment. It was really weird. Their worst fear was that somebody in Europe would call up, through some kind of a network, to a British Telephone installation, and get through it into the Atlantic link and get to the United States, and somehow bypass the fifteen cent toll, and, "Christ," I said, "this is just a research and development thing. If we can make it work, if it really turns out to be a great idea, we can figure out about rates and stuff." We wanted to extend an Arpanet link -- we needed in a desperate way to extend the Arpanet link to Stuttgart, and to some American military base down there -- I forget the name of it -- and they would never let us have the one little link.
The history of the Internet has its origin in the efforts of scientists and engineers to build and interconnect computer networks. The Internet Protocol Suite, the set of rules used to communicate between networks and devices on the Internet, arose from research and development in the United States and involved international collaboration, particularly with researchers in the United Kingdom and France.
Internetworking is the practice of interconnecting multiple computer networks, such that any pair of hosts in the connected networks can exchange messages irrespective of their hardware-level networking technology. The resulting system of interconnected networks is called an internetwork, or simply an internet.
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP). Early versions of this networking model were known as the Department of Defense (DoD) model because the research and development were funded by the United States Department of Defense through DARPA.
Stephen D. Crocker is an American Internet pioneer. In 1969, he created the ARPA "Network Working Group" and the Request for Comments series. He served as chair of the board of the Internet Corporation for Assigned Names and Numbers (ICANN) from 2011 through 2017.
A datagram is a basic transfer unit associated with a packet-switched network. Datagrams are typically structured in header and payload sections. Datagrams provide a connectionless communication service across a packet-switched network. The delivery, arrival time, and order of arrival of datagrams need not be guaranteed by the network.
In telecommunications, packet switching is a method of grouping data into packets that are transmitted over a digital network. Packets are made of a header and a payload. Data in the header is used by networking hardware to direct the packet to its destination, where the payload is extracted and used by an operating system, application software, or higher layer protocols. Packet switching is the primary basis for data communications in computer networks worldwide.
The end-to-end principle is a design framework in computer networking. In networks designed according to this principle, guaranteeing certain application-specific features, such as reliability and security, requires that they reside in the communicating end nodes of the network. Intermediary nodes, such as gateways and routers, that exist to establish the network, may implement these to improve efficiency but cannot guarantee end-to-end correctness.
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. Both technologies became the technical foundation of the Internet. The ARPANET was established by the Advanced Research Projects Agency of the United States Department of Defense.
Donald Watts Davies, was a Welsh computer scientist and Internet pioneer who was employed at the UK National Physical Laboratory (NPL).
The CYCLADES computer network was a French research network created in the early 1970s. It was one of the pioneering networks experimenting with the concept of packet switching and, unlike the ARPANET, was explicitly designed to facilitate internetworking.
Larry Roberts was an American computer scientist and Internet pioneer.
Peter Thomas Kirstein was a British computer scientist who played a role in the creation of the Internet. He made the first internetworking connection on the ARPANET in 1973, by providing a link to British academic networks, and was instrumental in defining and implementing TCP/IP alongside Vint Cerf and Bob Kahn.
NORSAR is a foundation established in 1968 as part of the Norwegian-US agreement for the detection of earthquakes and nuclear explosions. The name derives from the foundation's original project, the Norwegian Seismic Array.
The NPL network, or NPL Data Communications Network, was a local area computer network operated by a team from the National Physical Laboratory (NPL) in London that pioneered the concept of packet switching.
The Packet Radio Network (PRNET) was a set of early, experimental mobile ad hoc networks whose technologies evolved over time. It was funded by the Advanced Research Projects Agency (ARPA). Major participants in the project included BBN Technologies, Hazeltine Corporation, Rockwell International's Collins division, and SRI International.
Roger Anthony Scantlebury is a British computer scientist and Internet pioneer who worked at the National Physical Laboratory (NPL) and later at Logica.
The International Network Working Group (INWG) was a group of prominent computer science researchers in the 1970s who studied and developed standards and protocols for interconnection of computer networks. Set up in 1972 as an informal group to consider the technical issues involved in connecting different networks, its goal was to develop an international standard protocol for internetworking. INWG became a subcommittee of the International Federation for Information Processing (IFIP) the following year. Concepts developed by members of the group contributed to the Protocol for Packet Network Intercommunication proposed by Vint Cerf and Bob Kahn in 1974 and the Transmission Control Protocol and Internet Protocol (TCP/IP) that emerged later.
The Protocol Wars were a long-running debate in computer science that occurred from the 1970s to the 1990s, when engineers, organizations and nations became polarized over the issue of which communication protocol would result in the best and most robust networks. This culminated in the Internet–OSI Standards War in the 1980s and early 1990s, which was ultimately "won" by the Internet protocol suite (TCP/IP) by the mid-1990s when it became the dominant protocol suite through rapid adoption of the Internet.
David Corydon Walden was an American computer scientist and Internet pioneer who contributed to the engineering development of the ARPANET, a precursor of the modern Internet. He specifically contributed to the Interface Message Processor, which was the packet switching node for the ARPANET. Walden was a contributor to IEEE Computer Society's Annals of the History of Computing and was a member of the TeX Users Group.
The authors wish to thank a number of colleagues for helpful comments during early discussions of international network protocols, especially R. Metcalfe, R. Scantlebury, D. Walden, and H. Zimmerman; D. Davies and L. Pouzin who constructively commented on the fragmentation and accounting issues; and S. Crocker who commented on the creation and destruction of associations.
In the early 1970s Mr Pouzin created an innovative data network that linked locations in France, Italy and Britain. Its simplicity and efficiency pointed the way to a network that could connect not just dozens of machines, but millions of them. It captured the imagination of Dr Cerf and Dr Kahn, who included aspects of its design in the protocols that now power the internet.