In telecommunications, packet switching is a method of grouping data that is transmitted over a digital network into packets. 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 application software. Packet switching is the primary basis for data communications in computer networks worldwide.
In the early 1960s, American computer scientist Paul Baran developed the concept Distributed Adaptive Message Block Switching, with the goal of providing a fault-tolerant, efficient routing method for telecommunication messages as part of a research program at the RAND Corporation, funded by the US Department of Defense. This concept contradicted then-established principles of pre-allocation of network bandwidth, exemplified by the development of telecommunications in the Bell System. The new concept found little resonance among network implementers until the independent work of British computer scientist Donald Davies at the National Physical Laboratory (United Kingdom) in 1965. Davies is credited with coining the modern term packet switching and inspiring numerous packet switching networks in the decade following, including the incorporation of the concept into the design of the ARPANET in the United States.
A simple definition of packet switching is:
The routing and transferring of data by means of addressed packets so that a channel is occupied during the transmission of the packet only, and upon completion of the transmission the channel is made available for the transfer of other traffic
Packet switching allows delivery of variable bit rate data streams, realized as sequences of packets, over a computer network which allocates transmission resources as needed using statistical multiplexing or dynamic bandwidth allocation techniques. As they traverse networking hardware, such as switches and routers, packets are received, buffered, queued, and retransmitted (stored and forwarded), resulting in variable latency and throughput depending on the link capacity and the traffic load on the network. Packets are normally forwarded by intermediate network nodes asynchronously using first-in, first-out buffering, but may be forwarded according to some scheduling discipline for fair queuing, traffic shaping, or for differentiated or guaranteed quality of service, such as weighted fair queuing or leaky bucket. Packet-based communication may be implemented with or without intermediate forwarding nodes (switches and routers). In case of a shared physical medium (such as radio or 10BASE5), the packets may be delivered according to a multiple access scheme.
Packet switching contrasts with another principal networking paradigm, circuit switching, a method which pre-allocates dedicated network bandwidth specifically for each communication session, each having a constant bit rate and latency between nodes. In cases of billable services, such as cellular communication services, circuit switching is characterized by a fee per unit of connection time, even when no data is transferred, while packet switching may be characterized by a fee per unit of information transmitted, such as characters, packets, or messages.
A packet switch has four components: input ports, output ports, routing processor, and switching fabric.
The concept of switching small blocks of data was first explored independently by Paul Baran at the RAND Corporation in the early 1960s in the US and Donald Davies at the National Physical Laboratory (NPL) in the UK in 1965.
In the late 1950s, the US Air Force established a wide area network for the Semi-Automatic Ground Environment (SAGE) radar defense system. Recognizing vulnerabilities in this network, the Air Force sought a system that might survive a nuclear attack to enable a response, thus diminishing the attractiveness of the first strike advantage by enemies (see Mutual assured destruction). Baran developed the concept of distributed adaptive message block switching in support of the Air Force initiative. The concept was first presented to the Air Force in the summer of 1961 as briefing B-265, later published as RAND report P-2626 in 1962, and finally in report RM 3420 in 1964. Report P-2626 described a general architecture for a large-scale, distributed, survivable communications network. The work focuses on three key ideas: use of a decentralized network with multiple paths between any two points, dividing user messages into message blocks, and delivery of these messages by store and forward switching.
Davies independently developed a similar message routing concept in 1965. He coined the term packet switching, and proposed building a commercial nationwide data network in the UK. He gave a talk on the proposal in 1966, after which a person from the Ministry of Defence (MoD) told him about Baran's work. Roger Scantlebury, a member of Davies' team met Lawrence Roberts at the 1967 Symposium on Operating Systems Principles and suggested it for use in the ARPANET. Davies had chosen some of the same parameters for his original network design as did Baran, such as a packet size of 1024 bits. In 1966, Davies proposed that a network should be built at the laboratory to serve the needs of NPL and prove the feasibility of packet switching. To deal with packet permutations (due to dynamically updated route preferences) and to datagram losses (unavoidable when fast sources send to a slow destinations), he assumed that "all users of the network will provide themselves with some kind of error control", thus inventing what came to be known the end-to-end principle. After a pilot experiment in 1969, the NPL Data Communications Network entered service in 1970.
Leonard Kleinrock conducted research into queueing theory for his doctoral dissertation at MIT in 1961-2 and published it as a book in 1964 in the field of message switching. In 1968, Lawrence Roberts contracted with Kleinrock at UCLA to carry out theoretical work to model the performance of the ARPANET, which underpinned the development of the network in the early 1970s. The NPL team also carried out simulation work on packet networks, including datagram networks.
The French CYCLADES network, designed by Louis Pouzin in the early 1970s, was the first to implement the end-to-end principle of Davies, and make the hosts responsible for the reliable delivery of data on a packet-switched network, rather than this being a service of the network itself. His team was thus first to tackle the highly complex problem of providing user applications with a reliable virtual circuit service while using a best effort network service, an early contribution to what will be Transmission Control Protocol (TCP).
In May 1974, Vint Cerf and Bob Kahn described the Transmission Control Program, an internetworking protocol for sharing resources using packet-switching among the nodes. The specifications of the TCP were then published in RFC 675 (Specification of Internet Transmission Control Program), written by Vint Cerf, Yogen Dalal and Carl Sunshine in December 1974. This monolithic protocol was later layered as the Transmission Control Protocol, TCP, atop the Internet Protocol, IP.
Beginning in the mid-1990s, Leonard Kleinrock sought to be recognized as the "father of modern data networking". However, Kleinrock's claims that his work in the early 1960s originated the concept of packet switching and that this work was the source of the packet switching concepts used in the ARPANET are disputed, including by Robert Taylor, Paul Baran, and Donald Davies. Baran and Davies are recognized by historians and the U.S. National Inventors Hall of Fame for independently inventing the concept of digital packet switching used in modern computer networking including the Internet.
Connectionless and connection-oriented modes
Packet switching may be classified into connectionless packet switching, also known as datagram switching, and connection-oriented packet switching, also known as virtual circuit switching. Examples of connectionless systems are Ethernet, Internet Protocol (IP), and the User Datagram Protocol (UDP). Connection-oriented systems include X.25, Frame Relay, Multiprotocol Label Switching (MPLS), and the Transmission Control Protocol (TCP).
In connectionless mode each packet is labeled with a destination address, source address, and port numbers. It may also be labeled with the sequence number of the packet. This information eliminates the need for a pre-established path to help the packet find its way to its destination, but means that more information is needed in the packet header, which is therefore larger. The packets are routed individually, sometimes taking different paths resulting in out-of-order delivery. At the destination, the original message may be reassembled in the correct order, based on the packet sequence numbers. Thus a virtual circuit carrying a byte stream is provided to the application by a transport layer protocol, although the network only provides a connectionless network layer service.
Connection-oriented transmission requires a setup phase to establish the parameters of communication before any packet is transferred. The signaling protocols used for setup allow the application to specify its requirements and discover link parameters. Acceptable values for service parameters may be negotiated. The packets transferred may include a connection identifier rather than address information and the packet header can be smaller, as it only needs to contain this code and any information, such as length, timestamp, or sequence number, which is different for different packets. In this case, address information is only transferred to each node during the connection setup phase, when the route to the destination is discovered and an entry is added to the switching table in each network node through which the connection passes. When a connection identifier is used, routing a packet requires the node to look up the connection identifier in a table.
Connection-oriented transport layer protocols such as TCP provide a connection-oriented service by using an underlying connectionless network. In this case, the end-to-end principle dictates that the end nodes, not the network itself, are responsible for the connection-oriented behavior.
Packet switching in networks
Packet switching is used to optimize the use of the channel capacity available in digital telecommunication networks, such as computer networks, and minimize the transmission latency (the time it takes for data to pass across the network), and to increase robustness of communication.
Packet switching is used in the Internet and most local area networks. The Internet is implemented by the Internet Protocol Suite using a variety of Link Layer technologies. For example, Ethernet and Frame Relay are common. Newer mobile phone technologies (e.g., GSM, LTE) also use packet switching. Packet switching is associated with connectionless networking because, in these systems, no connection agreement needs to be established between communicating parties prior to exchanging data.
X.25 is a notable use of packet switching in that, despite being based on packet switching methods, it provides virtual circuits to the user. These virtual circuits carry variable-length packets. In 1978, X.25 provided the first international and commercial packet switching network, the International Packet Switched Service (IPSS). Asynchronous Transfer Mode (ATM) also is a virtual circuit technology, which uses fixed-length cell relay connection oriented packet switching.
Technologies such as Multiprotocol Label Switching (MPLS) and the Resource Reservation Protocol (RSVP) create virtual circuits on top of datagram networks. MPLS and its predecessors, as well as ATM, have been called "fast packet" technologies. MPLS, indeed, has been called "ATM without cells". Virtual circuits are especially useful in building robust failover mechanisms and allocating bandwidth for delay-sensitive applications.
The history of packet-switched networks can be divided into three overlapping eras: early networks before the introduction of X.25 and the OSI model; the X.25 era when many postal, telephone, and telegraph (PTT) companies provided public data networks with X.25 interfaces; and the Internet era.
Research into packet switching at the National Physical Laboratory (NPL) began with a proposal for a wide-area network in 1965, and a local-area network in 1966. ARPANET funding was secured in 1966 by Bob Taylor, and planning began in 1967 when he hired Larry Roberts. The NPL network, ARPANET, and SITA HLN became operational in 1969. Before the introduction of X.25 in 1973, about twenty different network technologies had been developed. Two fundamental differences involved the division of functions and tasks between the hosts at the edge of the network and the network core. In the datagram system, operating according to the end-to-end principle, the hosts have the responsibility to ensure orderly delivery of packets. In the virtual call system, the network guarantees sequenced delivery of data to the host. This results in a simpler host interface but complicates the network. The X.25 protocol suite uses this network type.
AppleTalk is a proprietary suite of networking protocols developed by Apple in 1985 for Apple Macintosh computers. It was the primary protocol used by Apple devices through the 1980s and 1990s. AppleTalk included features that allowed local area networks to be established ad hoc without the requirement for a centralized router or server. The AppleTalk system automatically assigned addresses, updated the distributed namespace, and configured any required inter-network routing. It was a plug-n-play system.
AppleTalk implementations were also released for the IBM PC and compatibles, and the Apple IIGS. AppleTalk support was available in most networked printers, especially laser printers, some file servers and routers. AppleTalk support was terminated in 2009, replaced by TCP/IP protocols.
BNRNET was a network which Bell-Northern Research developed for internal use. It initially had only one host but was designed to support many hosts. BNR later made major contributions to the CCITT X.25 project.
The CYCLADES packet switching network was a French research network designed and directed by Louis Pouzin. First demonstrated in 1973, it was developed to explore alternatives to the early ARPANET design and to support network research generally. It was the first network to use the end-to-end principle and make the hosts responsible for reliable delivery of data, rather than the network itself. Concepts of this network influenced later ARPANET architecture.
DECnet is a suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers. It evolved into one of the first peer-to-peer network architectures, thus transforming DEC into a networking powerhouse in the 1980s. Initially built with three layers, it later (1982) evolved into a seven-layer OSI-compliant networking protocol. The DECnet protocols were designed entirely by Digital Equipment Corporation. However, DECnet Phase II (and later) were open standards with published specifications, and several implementations were developed outside DEC, including one for Linux.
DDX-1 was an experimental network from Nippon PTT. It mixed circuit switching and packet switching. It was succeeded by DDX-2.
The European Informatics Network (EIN), originally called COST 11, was a project beginning in 1971 to link networks in Britain, France, Italy, Switzerland and Euratom. Six other European countries also participated in the research on network protocols. Derek Barber directed the project and Roger Scantlebury led the UK technical contribution; both were from NPL. Work began in 1973 and it became operational in 1976 including nodes linking the NPL network and CYCLADES. The transport protocol of the EIN was the basis of the one adopted by the International Networking Working Group. EIN was replaced by Euronet in 1979.
The Experimental Packet Switched Service (EPSS) was an experiment of the UK Post Office Telecommunications based on the Coloured Book protocols defined by the UK academic community in 1975. It was the first public data network in the UK when it began operating in 1977. Ferranti supplied the hardware and software. The handling of link control messages (acknowledgements and flow control) was different from that of most other networks.
As General Electric Information Services (GEIS), General Electric was a major international provider of information services. The company originally designed a telephone network to serve as its internal (albeit continent-wide) voice telephone network.
In 1965, at the instigation of Warner Sinback, a data network based on this voice-phone network was designed to connect GE's four computer sales and service centers (Schenectady, New York, Chicago, and Phoenix) to facilitate a computer time-sharing service.
After going international some years later, GEIS created a network data center near Cleveland, Ohio. Very little has been published about the internal details of their network. The design was hierarchical with redundant communication links.
The Internetwork Packet Exchange (IPX) and Sequenced Packet Exchange (SPX) are Novell networking protocols from the 1980s derived from Xerox Network Systems' IDP and SPP protocols, respectively which date back to the 1970s. IPX/SPX was used primarily on networks using the Novell NetWare operating systems.
Merit Network, an independent nonprofit organization governed by Michigan's public universities, was formed in 1966 as the Michigan Educational Research Information Triad to explore computer networking between three of Michigan's public universities as a means to help the state's educational and economic development. With initial support from the State of Michigan and the National Science Foundation (NSF), the packet-switched network was first demonstrated in December 1971 when an interactive host-to-host connection was made between the IBM mainframe systems at the University of Michigan in Ann Arbor and Wayne State University in Detroit. In October 1972, connections to the CDC mainframe at Michigan State University in East Lansing completed the triad. Over the next several years, in addition to host-to-host interactive connections, the network was enhanced to support terminal-to-host connections, host-to-host batch connections (remote job submission, remote printing, batch file transfer), interactive file transfer, gateways to the Tymnet and Telenet public data networks, X.25 host attachments, gateways to X.25 data networks, Ethernet attached hosts, and eventually TCP/IP; additionally, public universities in Michigan joined the network. All of this set the stage for Merit's role in the NSFNET project starting in the mid-1980s.
In 1965, Donald Davies of the National Physical Laboratory (United Kingdom) designed and proposed a national data network based on packet switching. The proposal was not taken up nationally, but by 1967, a pilot experiment had demonstrated the feasibility of packet switched networks.
By 1969 Davies had begun building the NPL network to meet the needs of the multidisciplinary laboratory and prove the technology under operational conditions. By 1976, 12 computers and 75 terminal devices were attached, and more were added until the network was replaced in 1986. NPL, followed by ARPANET, were the first two networks to use packet switching, and were interconnected in the early 1970s.
Octopus was a local network at Lawrence Livermore National Laboratory. It connected sundry hosts at the lab to interactive terminals and various computer peripherals including a bulk storage system.
PARC Universal Packet (PUP or Pup) was one of the two earliest internetwork protocol suites; it was created by researchers at Xerox PARC in the mid-1970s. The entire suite provided routing and packet delivery, as well as higher level functions such as a reliable byte stream, along with numerous applications. Further developments led to Xerox Network Systems (XNS).
RCP was an experimental network created by the French PTT. It was used to gain experience with packet switching technology before the specification of TRANSPAC was frozen. RCP was a virtual-circuit network in contrast to CYCLADES which was based on datagrams. RCP emphasised terminal-to-host and terminal-to-terminal connection; CYCLADES was concerned with host-to-host communication. TRANSPAC was introduced as an X.25 network. RCP influenced the specification of X.25.
"The experimental packet-switched Nordic telecommunication network SCANNET was implemented in Nordic technical libraries in the 1970s, and it included first Nordic electronic journal Extemplo. Libraries were also among first ones in universities to accommodate microcomputers for public use in the early 1980s."
SITA is a consortium of airlines. Its High Level Network became operational in 1969 at about the same time as ARPANET. It carried interactive traffic and message-switching traffic. As with many non-academic networks, very little has been published about it.
Systems Network Architecture
Systems Network Architecture (SNA) is IBM's proprietary networking architecture created in 1974. An IBM customer could acquire hardware and software from IBM and lease private lines from a common carrier to construct a private network.
Telenet was the first FCC-licensed public data network in the United States. Telenet was incorporated in 1973 and started operations in 1975. It was founded by Bolt Beranek & Newman with Larry Roberts as CEO as a means of making packet switching technology public. He had tried to interest AT&T in buying the technology, but the monopoly's reaction was that this was incompatible with their future. It initially used ARPANET technology but changed the host interface to X.25 and the terminal interface to X.29. It went public in 1979 and was then sold to GTE.
Tymnet was an international data communications network headquartered in San Jose, CA that utilized virtual call packet switched technology and used X.25, SNA/SDLC, BSC and ASCII interfaces to connect host computers (servers) at thousands of large companies, educational institutions, and government agencies. Users typically connected via dial-up connections or dedicated async connections. The business consisted of a large public network that supported dial-up users and a private network business that allowed government agencies and large companies (mostly banks and airlines) to build their own dedicated networks. The private networks were often connected via gateways to the public network to reach locations not on the private network. Tymnet was also connected to dozens of other public networks in the U.S. and internationally via X.25/X.75 gateways. (Interesting note: Tymnet was not named after Mr. Tyme. Another employee suggested the name.)
Xerox Network Systems (XNS) was a protocol suite promulgated by Xerox, which provided routing and packet delivery, as well as higher level functions such as a reliable stream, and remote procedure calls. It was developed from PARC Universal Packet (PUP).
There were two kinds of X.25 networks. Some such as DATAPAC and TRANSPAC were initially implemented with an X.25 external interface. Some older networks such as TELENET and TYMNET were modified to provide a X.25 host interface in addition to older host connection schemes. DATAPAC was developed by Bell Northern Research which was a joint venture of Bell Canada (a common carrier) and Northern Telecom (a telecommunications equipment supplier). Northern Telecom sold several DATAPAC clones to foreign PTTs including the Deutsche Bundespost. X.75 and X.121 allowed the interconnection of national X.25 networks. A user or host could call a host on a foreign network by including the DNIC of the remote network as part of the destination address.
AUSTPAC was an Australian public X.25 network operated by Telstra. Started by Telecom Australia in the early 1980s, AUSTPAC was Australia's first public packet-switched data network, supporting applications such as on-line betting, financial applications—the Australian Tax Office made use of AUSTPAC—and remote terminal access to academic institutions, who maintained their connections to AUSTPAC up until the mid-late 1990s in some cases. Access can be via a dial-up terminal to a PAD, or, by linking a permanent X.25 node to the network.
Datanet 1 was the public switched data network operated by the Dutch PTT Telecom (now known as KPN). Strictly speaking Datanet 1 only referred to the network and the connected users via leased lines (using the X.121 DNIC 2041), the name also referred to the public PAD service Telepad (using the DNIC 2049). And because the main Videotex service used the network and modified PAD devices as infrastructure the name Datanet 1 was used for these services as well. Although this use of the name was incorrect all these services were managed by the same people within one department of KPN contributed to the confusion.
Deutsche Bundespost operated this national network in Germany. The technology was acquired from Northern Telecom.
Nine member states of the European Economic Community contracted with Logica and the French company SESA to set up a joint venture in 1975 to undertake the Euronet development, using X.25 protocols to form virtual circuits. It was to replace EIN and established a network in 1979 linking a number of European countries until 1984 when the network was handed over to national PTTs.
Hitachi designed a private network system for sale as a turnkey package to multi-national organizations. In addition to providing X.25 packet switching, message switching software was also included. Messages were buffered at the nodes adjacent to the sending and receiving terminals. Switched virtual calls were not supported, but through the use of "logical ports" an originating terminal could have a menu of pre-defined destination terminals. 
In 1978, X.25 provided the first international and commercial packet switching network, the International Packet Switched Service (IPSS).
JANET was the UK academic and research network, linking all universities, higher education establishments, publicly funded research laboratories. The X.25 network, which used the Coloured Book protocols, was based mainly on GEC 4000 series switches, and run X.25 links at up to 8 Mbit/s in its final phase before being converted to an IP based network. The JANET network grew out of the 1970s SRCnet, later called SERCnet.
Packet Switch Stream (PSS) was the UK Post Office (later to become British Telecom) national X.25 network with a DNIC of 2342. British Telecom renamed PSS under its GNS (Global Network Service) name, but the PSS name has remained better known. PSS also included public dial-up PAD access, and various InterStream gateways to other services such as Telex.
TRANSPAC was the national X.25 network in France. It was developed locally at about the same time as DATAPAC in Canada. The development was done by the French PTT and influenced by the experimental RCP network. It began operation in 1978, and served both commercial users and, after Minitel began, consumers.
VENUS-P was an international X.25 network that operated from April 1982 through March 2006. At its subscription peak in 1999, VENUS-P connected 207 networks in 87 countries.
Venepaq is the national X.25 public network in Venezuela. It is run by Cantv and allow direct connection and dial up connections. Provides nationalwide access at very low cost. It provides national and international access. Venepaq allow connection from 19.2 kbit/s to 64 kbit/s in direct connections, and 1200, 2400 and 9600 bit/s in dial up connections.
When Internet connectivity was made available to anyone who could pay for an ISP subscription, the distinctions between national networks blurred. The user no longer saw network identifiers such as the DNIC. Some older technologies such as circuit switching have resurfaced with new names such as fast packet switching. Researchers have created some experimental networks to complement the existing Internet.
The Computer Science Network (CSNET) was a computer network funded by the U.S. National Science Foundation (NSF) that began operation in 1981. Its purpose was to extend networking benefits, for computer science departments at academic and research institutions that could not be directly connected to ARPANET, due to funding or authorization limitations. It played a significant role in spreading awareness of, and access to, national networking and was a major milestone on the path to development of the global Internet.
Internet2 is a not-for-profit United States computer networking consortium led by members from the research and education communities, industry, and government. The Internet2 community, in partnership with Qwest, built the first Internet2 Network, called Abilene, in 1998 and was a prime investor in the National LambdaRail (NLR) project. In 2006, Internet2 announced a partnership with Level 3 Communications to launch a brand new nationwide network, boosting its capacity from 10 Gbit/s to 100 Gbit/s. In October, 2007, Internet2 officially retired Abilene and now refers to its new, higher capacity network as the Internet2 Network.
The National Science Foundation Network (NSFNET) was a program of coordinated, evolving projects sponsored by the National Science Foundation (NSF) beginning in 1985 to promote advanced research and education networking in the United States. NSFNET was also the name given to several nationwide backbone networks operating at speeds of 56 kbit/s, 1.5 Mbit/s (T1), and 45 Mbit/s (T3) that were constructed to support NSF's networking initiatives from 1985-1995. Initially created to link researchers to the nation's NSF-funded supercomputing centers, through further public funding and private industry partnerships it developed into a major part of the Internet backbone.
NSFNET regional networks
In addition to the five NSF supercomputer centers, NSFNET provided connectivity to eleven regional networks and through these networks to many smaller regional and campus networks in the United States. The NSFNET regional networks were:
- BARRNet, the Bay Area Regional Research Network in Palo Alto, California;
- CERFNET, California Education and Research Federation Network in San Diego, California, serving California and Nevada;
- CICNet, the Committee on Institutional Cooperation Network via the Merit Network in Ann Arbor, Michigan and later as part of the T3 upgrade via Argonne National Laboratory outside of Chicago, serving the Big Ten Universities and the University of Chicago in Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin;
- Merit/MichNet in Ann Arbor, Michigan serving Michigan, formed in 1966, still in operation as of 2016;
- MIDnet in Lincoln, Nebraska serving Arkansas, Iowa, Kansas, Missouri, Nebraska, Oklahoma, and South Dakota;
- NEARNET, the New England Academic and Research Network in Cambridge, Massachusetts, added as part of the upgrade to T3, serving Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont, established in late 1988, operated by BBN under contract to MIT, BBN assumed responsibility for NEARNET on 1 July 1993;
- NorthWestNet in Seattle, Washington, serving Alaska, Idaho, Montana, North Dakota, Oregon, and Washington, founded in 1987;
- NYSERNet, New York State Education and Research Network in Ithaca, New York;
- JVNCNet, the John von Neumann National Supercomputer Center Network in Princeton, New Jersey, serving Delaware and New Jersey;
- SESQUINET, the Sesquicentennial Network in Houston, Texas, founded during the 150th anniversary of the State of Texas;
- SURAnet, the Southeastern Universities Research Association network in College Park, Maryland and later as part of the T3 upgrade in Atlanta, Georgia serving Alabama, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virginia, sold to BBN in 1994; and
- Westnet in Salt Lake City, Utah and Boulder, Colorado, serving Arizona, Colorado, New Mexico, Utah, and Wyoming.
The National LambdaRail was launched in September 2003. It is a 12,000-mile high-speed national computer network owned and operated by the U.S. research and education community that runs over fiber-optic lines. It was the first transcontinental 10 Gigabit Ethernet network. It operates with high aggregate capacity of up to 1.6 Tbit/s and a high 40 Gbit/s bitrate, with plans for 100 Gbit/s. The upgrade never took place and NLR ceased operations in March 2014.
TransPAC, TransPAC2, and TransPAC3
TransPAC2 and TransPAC3, continuations of the TransPAC project, a high-speed international Internet service connecting research and education networks in the Asia-Pacific region to those in the US. TransPAC is part of the NSF’s International Research Network Connections (IRNC) program.
Very high-speed Backbone Network Service (vBNS)
The Very high-speed Backbone Network Service (vBNS) came on line in April 1995 as part of a National Science Foundation (NSF) sponsored project to provide high-speed interconnection between NSF-sponsored supercomputing centers and select access points in the United States. The network was engineered and operated by MCI Telecommunications under a cooperative agreement with the NSF. By 1998, the vBNS had grown to connect more than 100 universities and research and engineering institutions via 12 national points of presence with DS-3 (45 Mbit/s), OC-3c (155 Mbit/s), and OC-12c (622 Mbit/s) links on an all OC-12c backbone, a substantial engineering feat for that time. The vBNS installed one of the first ever production OC-48c (2.5 Gbit/s) IP links in February 1999 and went on to upgrade the entire backbone to OC-48c.
In June 1999 MCI WorldCom introduced vBNS+ which allowed attachments to the vBNS network by organizations that were not approved by or receiving support from NSF. After the expiration of the NSF agreement, the vBNS largely transitioned to providing service to the government. Most universities and research centers migrated to the Internet2 educational backbone. In January 2006, when MCI and Verizon merged, vBNS+ became a service of Verizon Business.
- Multi-bearer network
- Optical burst switching
- Packet radio
- Public switched data network
- Time-Driven Switching - a bufferless approach to packet switching
- Transmission delay
- Virtual private network
- Paul Baran, On Distributed Communications, Volume I–XI, Rand Corporation Research Report, August 1964
- Roberts, Dr. Lawrence G. (November 1978). "The Evolution of Packet Switching". Archived from the original on 24 March 2016. Retrieved 5 September 2017.
Almost immediately after the 1965 meeting, Donald Davies conceived of the details of a store-and-forward packet switching system
- Kirstein, Peter (28 July 1998). "Early Experiences with the ARPANET and INTERNET in the UK" (PDF). University College London. Archived from the original (PDF) on 10 August 2017. Retrieved 21 August 2017.
- Martin Weik - Fiber Optics Standard Dictionary Springer Science & Business Media 6 Dec 2012, 1219 pages, ISBN 1461560233 [Retrieved 2015-08-04]
- National Telecommunication Information Administration - Telecommunications: Glossary of Telecommunications Terms published by Government Institutes 1 Apr 1997, 480 pages, ISBN 1461732328, Volume 1037, Part 3 of Federal Standard [Retrieved 2015-08-04]
- Forouzan, Behrouz A.; Fegan, Sophia Chung (2007). Data Communications and Networking. Huga Media. ISBN 978-0-07-296775-3.
- Abbate, Jane (2000). Inventing the Internet. MIT Press. p. 37-8, 58-9. ISBN 978-0262261333.
- "Inductee Details - Donald Watts Davies". National Inventors Hall of Fame. Retrieved 6 September 2017; "Inductee Details - Paul Baran". National Inventors Hall of Fame. Retrieved 2020-05-09.
- Stewart, Bill (2000-01-07). "Paul Baran Invents Packet Switching". Living Internet. Retrieved 2008-05-08.
- Baran, Paul (May 27, 1960). "Reliable Digital Communications Using Unreliable Network Repeater Nodes" (PDF). The RAND Corporation: 1. Retrieved July 7, 2016. Cite journal requires
- Baran, Paul (1962). "RAND Paper P-2626".
- On Distributed Communications
- Baran, Paul (2002). "The beginnings of packet switching: some underlying concepts" (PDF). IEEE Communications Magazine. 40 (7): 42–48. doi:10.1109/MCOM.2002.1018006. ISSN 0163-6804.
Essentially all the work was defined by 1961, and fleshed out and put into formal written form in 1962. The idea of hot potato routing dates from late 1960.
- Monica, 1776 Main Street Santa; California 90401-3208. "Paul Baran and the Origins of the Internet". www.rand.org. Retrieved 2020-02-15.
- Davies, D. W. (17 March 1986), Oral History 189: D. W. Davies interviewed by Martin Campbell-Kelly at the National Physical Laboratory, Charles Babbage Institute University of Minnesota, Minneapolis, archived from the original on 29 July 2014, retrieved 21 July 2014
- Gillies, James; Cailliau, Robert (2000). How the Web was Born: The Story of the World Wide Web. Oxford University Press. p. 25. ISBN 978-0192862075.
- "A Digital Communication Network for Computers Giving Rapid Response at remote Terminals" (PDF). 1967. Retrieved 2020-09-15.
- C. Hempstead; W. Worthington (2005). Encyclopedia of 20th-Century Technology. Routledge. ISBN 9781135455514.
- Isaacson, Walter (2014). The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital Revolution. Simon and Schuster. p. 246. ISBN 9781476708690.
- Pelkey, James. "6.3 CYCLADES Network and Louis Pouzin 1971-1972". Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968-1988.
- Cerf, V.; Kahn, R. (1974). "A Protocol for Packet Network Intercommunication" (PDF). IEEE Transactions on Communications. 22 (5): 637–648. doi:10.1109/TCOM.1974.1092259. ISSN 1558-0857.
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.
- Cerf, Vinton; Dalal, Yogen; Sunshine, Carl (December 1974), RFC 675, Specification of Internet Transmission Control Protocol
- Hayward, G.; Gottlieb, A.; Jain, S.; Mahoney, D. (October 1987). "CMOS VLSI Applications in Broadband Circuit Switching". IEEE Journal on Selected Areas in Communications. 5 (8): 1231–1241. doi:10.1109/JSAC.1987.1146652. ISSN 1558-0008.
- Hui, J.; Arthurs, E. (October 1987). "A Broadband Packet Switch for Integrated Transport". IEEE Journal on Selected Areas in Communications. 5 (8): 1264–1273. doi:10.1109/JSAC.1987.1146650. ISSN 1558-0008.
- Gibson, Jerry D. (2018). The Communications Handbook. CRC Press. p. 34–4. ISBN 9781420041163.
- Isaacson, Walter (2014). The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital Revolution. Simon & Schuster. p. 244-5. ISBN 9781476708690.
This led to an outcry among many of the other Internet pioneers, who publicly attacked Kleinrock and said that his brief mention of breaking messages into smaller pieces did not come close to being a proposal for packet switching
- Alex McKenzie (2009), Comments on Dr. Leonard Kleinrock's claim to be "the Father of Modern Data Networking", retrieved April 23, 2015 "... there is nothing in the entire 1964 book that suggests, analyzes, or alludes to the idea of packetization."
- Trevor Harris, University of Wales (2009). "Who is the Father of the Internet?". Variety in Mass Communication Research.
Dr Willis H. Ware, Senior Computer Scientist and Research at the RAND Corporation, notes that Davies (and others) were troubled by what they regarded as in appropriate claims on the invention of packet switching
- Robert Taylor (November 22, 2001), "Birthing the Internet: Letters From the Delivery Room; Disputing a Claim", New York Times,
Authors who have interviewed dozens of Arpanet pioneers know very well that the Kleinrock-Roberts claims are not believed.
- Katie Hefner (November 8, 2001), "A Paternity Dispute Divides Net Pioneers", New York Times,
The Internet is really the work of a thousand people," Mr. Baran said. "And of all the stories about what different people have done, all the pieces fit together. It's just this one little case that seems to be an aberration.
- Donald Davies (2001), "A Historical Study of the Beginnings of Packet Switching", Computer Journal, British Computer Society, 44 (3): 152–162, doi:10.1093/comjnl/44.3.152,
I can find no evidence that he understood the principles of packet switching.[dead link]
- Scantlebury, Roger (25 June 2013). "Internet pioneers airbrushed from history". The Guardian. Retrieved 10 September 2017.
- "The real story of how the Internet became so vulnerable". Washington Post. Archived from the original on 2015-05-30. Retrieved 2020-02-18.
Historians credit seminal insights to Welsh scientist Donald W. Davies and American engineer Paul Baran
- "Inductee Details - Paul Baran". National Inventors Hall of Fame. Archived from the original on 6 September 2017. Retrieved 6 September 2017; "Inductee Details - Donald Watts Davies". National Inventors Hall of Fame. Archived from the original on 6 September 2017. Retrieved 6 September 2017.
- Interview with the author (of an MPLS-based VPN article) Archived 2007-09-29 at the Wayback Machine, G. Pildush
- Moore, Roger D. (August 2006). "This is a temporary index for a collection of papers about packet-switching in the 1970s". Retrieved 5 September 2017.
- Kirstein, Peter T. (1973). "A SURVEY OF PRESENT AMD PLANNED GENERAL PURPOSE EUROPEAN DATA AND COMPUTER NETWORKS". Retrieved 5 September 2017.
- National Research Council (U.S.). National Research Network Review Committee, Leonard Kleinrock; et al. (1988). Toward a National Research Network. National Academies. p. 40. ISBN 9780309581257.
- "A SURVEY OF THE CAPABILITIES OF 8 PACKET SWITCHING NETWORKS". 1975. Retrieved 5 September 2017.
Research in packet switching networks at the British National Physical Laboratory (NPL) predates ARPANET, having commenced in 1966.
- Taylor, Steve; Jim Metzler (2008). "Vint Cerf on why TCP/IP was so long in coming".
- "A History of Macintosh Networking" Archived 2006-10-16 at the Wayback Machine, Alan Oppenheimer, MacWorld Expo, January 2004
- Inside AppleTalk, Second Edition, Gursharan Sidhu, Richard Andrews and Alan Oppenheiner, Addison-Wesley, 1989, ISBN 0-201-55021-0
- Martel, C. C.; J. M. Cunningham; M. S. Grushcow. "THE BNR NETWORK: A CANADIAN EXPERIENCE WITH PACKET SWITCHING TECHNOLOGY". IFIP Congress 1974. pp. 10–14.
- "A Technical History of CYCLADES". Technical Histories of the Internet & other Network Protocols. Computer Science Department, University of Texas Austin. Archived from the original on 2013-09-01.
- "The Cyclades Experience: Results and Impacts", Zimmermann, H., Proc. IFIP'77 Congress, Toronto, August 1977, pp. 465–469
- Digital Equipment Corporation, Nineteen Fifty-Seven to the Present (PDF), Digital Equipment Corporation, 1978, p. 53, archived from the original (PDF) on 2017-06-30
- Wood, David C. (1975). "A Survey of the Capabilities of 8 Packet Switching Networks". Proceedings of Symposium on Computer Networks. Retrieved 2020-03-13.
- Barber, D L. (1975). "Cost project 11". ACM SIGCOMM Computer Communication Review. 5 (3): 12–15. doi:10.1145/1015667.1015669. S2CID 28994436.
- Scantlebury, Roger (1986). "X.25 - past, present and future". In Stokes, A. V. (ed.). Communications Standards: State of the Art Report. Pergamon. pp. 203–216. ISBN 978-1-4831-6093-1.
- "EIN (European Informatics Network)". Computer History Museum. Retrieved 2020-02-05.
- Abbate, Janet (2000). Inventing the Internet. MIT Press. p. 125. ISBN 978-0-262-51115-5.
- Davies, Donald Watts (1979). Computer networks and their protocols. John Wiley & Sons. pp. 464.
- Hardy, Daniel; Malleus, Guy (2002). Networks: Internet, Telephony, Multimedia: Convergences and Complementarities. Springer Science & Business Media. p. 505. ISBN 978-3-540-00559-9.
- Beauchamp, K. G. (2012-12-06). Interlinking of Computer Networks: Proceedings of the NATO Advanced Study Institute held at Bonas, France, August 28 – September 8, 1978. Springer Science & Business Media. p. 55. ISBN 978-94-009-9431-7.
- Davies, Howard; Bressan, Beatrice, eds. (2010). A history of international research networking: the people who made it happen. John Wiley & Sons. p. 2. ISBN 978-3527327102.
- Bright, Roy D.; Smith, Michael A. (1973). "EXPERIMENTAL PACKET SWITCHING PROJECT OF THE UK POST OFFICE". Proceedings of the NATO Advanced Study Institute on Computer Communication Networks. Sussex, United Kingdom: Noordhoff International Publishing. pp. 435–44.
- Pearson, DJ; Wilkin, D (1974). "Some Design Aspects of a public packet switching network". Proceedings of the 2nd ICCC 74. pp. 199–213.
- Schwartz, Mischa; Boorstyn, Rober R.; Pickholtz, Raymond L. (November 1972). "Terminal-Oriented Computer-Communication Networks". Proceedings of the IEEE. 60 (11): 1408–23. doi:10.1109/proc.1972.8912.
- Kirstein, Peter T. (1973). "A SURVEY OF PRESENT AND PLANNED GENERAL PURPOSE EUROPEAN DATA AND COMPUTER NETWORKS". Proceedings of the NATO Advanced Study Institute on Computer Communication Networks. Sussex, United Kingdom: Noordhoff International Publishing.
- "IPSANET Documents".
- "Maintaining IPX Compatibility During a Migration to TCP/IP on a NetWare Network", Rich Lee, Novell, 1 March 1998. Retrieved 3 September 2013.
- Merit receives administrative services under an agreement with the University of Michigan.
- John Mulcahy (1989), A Chronicle of Merit's Early History, Ann Arbor, Michigan: Merit Network, archived from the original on 2009-02-07
- Merit Network Timeline: 1970–1979, Ann Arbor, Michigan: Merit Network, archived from the original on 2016-01-01
- Merit Network Timeline: 1980–1989, Ann Arbor, Michigan: Merit Network, archived from the original on 2016-01-01
- K.G. Coffman; A.M. Odlyzco (22 May 2002). "Optics and Photonics". In I. Kaminow; T. Li (eds.). Optical Fiber Telecommunications IV-B: Systems and Impairments. Academic Press. ISBN 978-0080513195. Retrieved 2015-08-15.
- B. Steil; David G. Victor; Richard R. Nelson, eds. (1 Jan 2002). Technological Innovation and Economic Performance. Princeton University Press. ISBN 978-0691090917. Retrieved 2015-08-15.
- Scantlebury, R. A.; Wilkinson, P.T. (1974). "The National Physical Laboratory Data Communications Network". Proceedings of the 2nd ICCC 74. pp. 223–228.
- Ward, Mark (October 29, 2009). "Celebrating 40 years of the net". BBC News.
- "The National Physical Laboratory Data Communications Netowrk". 1974. Retrieved 5 September 2017.
- John S, Quarterman; Josiah C, Hoskins (1986). "Notable computer networks". Communications of the ACM. 29 (10): 932–971. doi:10.1145/6617.6618. S2CID 25341056.
The first packet-switching network was implemented at the National Physical Laboratories in the United Kingdom. It was quickly followed by the ARPANET in 1969.
- "Donald Davies". thocp.net. Archived from the original on 2020-11-05. Retrieved 2017-08-28.
- "Donald Davies". internethalloffame.org.
- Mendicino, Samuel F. (1972). "1970 OCTOPUS: THE LAWRENCE RADIATION LABORATORY NETWORK". Computer Networks. Englewood Cliffs, N.J.: Prentice-Hall Inc.: 95–100.
- Pehrson, David L. (1970). "AN ENGINEERING VIEW OF THE LRL OCTOPUS COMPUTER NETWORK".
- Fletcher, John G. (1975). "Principles of Design in the Octopus Computer network".
- Burnett, D.J.; Sethi, H.R. (1977). "Packet Switching at Philips Research Laboratories". Computer Networks. 1 (6): 341–348. doi:10.1016/0376-5075(77)90010-1.
- David R. Boggs; John F. Shoch; Edward A. Taft; Robert M. Metcalfe (April 1980). "Pup: An Internetwork Architecture". IEEE Transactions on Communications. 28 (4): 612–624. doi:10.1109/TCOM.1980.1094684. S2CID 62684407.
- "Discussion of Technical Choices made for Transpac" (PDF).
- Després, R. (1974). "RCP, THE EXPERIMENTAL PACKET-SWITCHED DATA TRANSMISSION SERVICE OF THE FRENCH PTT". Proceedings of ICCC 74. pp. 171–85.
- Bache, A.; Matras, Y. (1976). "Fundamental Choices in the Development of RCP, the Experimental Packet-Switching Data Transmission Service of the French PTT". Proceedings of ICCC 76. pp. 311–16.
- Bache, A.; L. Guillou; H. Layec; B. Long; Y. Matras (1976). "RCP, the Experimental Packet-Switched Data Transmission Service of the French PTT: History, Connections, Control". Proceedings of ICCC 76.
- Alarcia, G.; Herrera, S. (1974). "C.T.N.E.'s PACKET SWITCHING NETWORK. ITS APPLICATIONS". Proceedings of 2nd ICCC 74. pp. 163–170.
- Cuenca, L. (1980). "A PUBLIC PACKET SWITCHING DATA COMMUNICATIONS NETWORK: EIGHT YEARS OF OPERATING EXPERIENCE". Conference Record of ICC 80. IEEE. pp. 39.3.1–39.3.5.
- Lavandera, Luis (1980). "ARCHITECTURE, PROTOCOLS AND PERFORMANCE OF RETD". Conference Record of ICC 80. IEEE. pp. 28.4.1–28.4.5.
- Haarala, Arja-Riitta (2001). "Libraries as key players at the local level". doi:10.18452/1040. Cite journal requires
- Chretien, G.J.; Konig, W.M.; Rech, J.H. (1973). "The SITA Network". Proceedings of the NATO Advanced Study Institute on Computer Communication Networks. Sussex, United Kingdom: Noordhoff International Publishing. pp. 373–396.
- Sundstrom, R.J.; G.D. Schultz (1980). "1980 SNA'S First Six Years: 1974-1980". Proceedings of 5th ICCC 80. pp. 578–585.
- "Electronic post for switching data". Timothy Johnson. New Scientist. May 13, 1976
- Mathison, S.L. Roberts, L.G.; Walker, P.M., The history of telenet and the commercialization of packet switching in the U.S., Communications Magazine, IEEE, May 2012
- TYMES, LA ROY W. "TYMNET — A terminal oriented communication network". Proceedings of the SJCC 1971. 38. pp. 211–16.
- TYMES, LA ROY W. (April 1981). "Routing and Flow Control in TYMNET". IEEE Transactions on Communications. COM-29 (4): 392–98. doi:10.1109/tcom.1981.1095020.
- Xerox System Integration Standard - Internet Transport Protocols, Xerox, Stamford, 1981.
- "Chapter 12: Xerox Network Systems", AIX Version 4.3 Communications Programming Concepts, International Business Machines, October 1997.
- Andrew Colley (28 January 2004). "Telstra drops Austpac; reaches for finance market". Retrieved 21 December 2018.
- Maidasani, Dinesh (June 2009). Straight To The Point - Networking. Laxmi Publications Pvt Limited. ISBN 9788131805299.
- H.J. Steneker: Graduation Report on X.25 data services in GSM network Electrical Engineering - TUE, 16 May 1991. Chapter 3: page 20 and further, Retrieved 15 June 2011
- Parodi, Roberto (1992). Towards a New World in Computer Communication: Eleventh International Conference on Computer Communication, Genova, Italy, 1992 : Proceedings of the Conference. IOS Press. ISBN 978-90-5199-110-9.
- Telecommunications Directory. Gale Research. 2000. p. 593. ISBN 978-0-7876-3352-3.
- Gareth Locksley (1990). The Single European Market and the Information and Communication Technologies. Belhaven Press. p. 194. ISBN 978-1-85293-101-8.
- "Eircom Plc and the Department of Agriculture and Food; Mr Mark Henry and the Department of Agriculture and Food; Eircom Plc and the Department of Finance and Eircom Plc and Office of the Revenue Commissioners. - Office of the Information Commissioner". Retrieved 23 May 2017.[permanent dead link]
- Dunning, A.J. (1977-12-31). "Origins, development and future of the Euronet". Program. Emeraldinsight.com. 11 (4): 145–155. doi:10.1108/eb046759.
- Kerssens, Niels (2020). "Rethinking legacies in internet history: Euronet, lost (inter)networks, EU politics". Internet Histories. 4: 32–48. doi:10.1080/24701475.2019.1701919. ISSN 2470-1475.
- Tomaru, K.; T. Kato; S.I. Yamaguchi (1980). "A Private Packet Network and Its Application in A Worldwide Integrated Communication Network". Proceedings of ICCC '80. pp. 517–22.
- "1984-2014: 30 years of the Janet network" (PDF). Disc. Retrieved 23 September 2017.
- Wells, Mike (1988-11-01). "JANET-the United Kingdom Joint Academic Network". Serials. 1 (3): 28–36. doi:10.1629/010328. ISSN 1475-3308.
- "X.25 Virtual Circuits - Transpac in France - Pre-Internet Data Networking". doi:10.1109/MCOM.2010.5621965. S2CID 23639680. Cite journal requires
- Epstein, Nadine (1986-03-09). "Et Voila! Le Minitel". The New York Times.
- "KDDI to Close VENUS-P International Public Data Communications Service" Archived 2013-09-04 at archive.today, KDDI, 9 November 2005. Retrieved 3 September 2013.
- Mike C. Smith (7 September 2017). "What is Dedicated Internet Access?". Retrieved 21 December 2018.
- "The Internet—From Modest Beginnings". NSF website. Archived from the original on August 28, 2011. Retrieved September 30, 2011.
- Douglas Comer (October 1983). "History and overview of CSNET". Communications. 26 (10): 747–753. doi:10.1145/358413.358423. S2CID 11943330.
- "About Internet2", Retrieved on 2009-06-26
- "Optical networking: The next generation", Marguerite Reardon, CNET News, October 11, 2004
- "Speedy Internet2 gets 10x boost", Anick Jesdanun (AP), USAToday.com, October 11, 2007, Retrieved 26 June 2009.
- NSFNET: The Partnership That Changed The World, Web site for an event held to celebrate the NSFNET, November 2007
- "Retiring the NSFNET Backbone Service: Chronicling the End of an Era" Archived 2013-08-17 at the Wayback Machine, Susan R. Harris and Elise Gerich, ConneXions, Vol. 10, No. 4, April 1996
- "NSFNET: The Community", panel presentation slides, Doug Gale moderator, NSFNET: The Partnership That Changed The World, 29 November 2007
- "Merit–Who, What, and Why, Part One: The Early Years, 1964-1983" Archived 2013-04-23 at the Wayback Machine, Eric M. Aupperle, Merit Network, Inc., in Library Hi Tech, vol. 16, No. 1 (1998)
- "BBN to operate NEARnet", MIT News, 14 July 1993
- "About NorthWestNet", NorthWestNet User Services Internet Resource Guide, NorthWestNet Academic Computing Consortium, Inc., 24 March 1992 accessed 3 July 2012
- Michael Feldman (October 28, 2008). "National LambdaRail Opens for Business". HPCwire. Retrieved June 6, 2013.
- "About NLR" Archived 2013-09-04 at archive.today, National LambdaRail, 3 September 2013.
- "International TransPAC2 Inaugurated" Archived 2013-06-20 at archive.today, HPC Wire, 8 April 2005.
- "TransPAC website" Archived 2013-07-17 at the Wayback Machine. Retrieved 3 September 2013.
- "TransPAC3 - Asia-US High Performance International Networking", International Research Network Connections Program (IRNC), U.S. National Science Foundation, October 2011. Retrieved 3 September 2013.
- NSF Solicitation 93-52 Archived 2016-03-05 at the Wayback Machine - Network Access Point Manager, Routing Arbiter, Regional Network Providers, and Very High Speed Backbone Network Services Provider for NSFNET and the NREN(SM) Program, May 6, 1993
- "vBNS: not your father's Internet", John Jamison, Randy Nicklas, Greg Miller, Kevin Thompson, Rick Wilder, Laura Cunningham and Chuck Song, IEEE Spectrun, Volume 35 Issue 7 (July 1998), pp. 38-46.
- "MCI WorldCom Introduces Next Generation vBNS+ For All Higher Education And Research Organizations", Verizon Business News, June 23, 1999
- "Verizon and MCI Close Merger, Creating a Stronger Competitor for Advanced Communications Services", Verizon Business News, January 6, 2006
- vBNS+, at http://www.verizonbusiness.com Home > Solutions > Government > Federal Government > Contract Vehicles > FTS2001 Bridge > Products
- Paul Baran et al., On Distributed Communications, Volumes I-XI (RAND Corporation Research Documents, August, 1964)
- Paul Baran, On Distributed Communications: I Introduction to Distributed Communications Network (RAND Memorandum RM-3420-PR. August 1964)
- Paul Baran, On Distributed Communications Networks, (IEEE Transactions on Communications Systems, Vol. CS-12 No. 1, pp. 1–9, March 1964)
- D. W. Davies, K. A. Bartlett, R. A. Scantlebury, and P. T. Wilkinson, A digital communications network for computers giving rapid response at remote terminals (ACM Symposium on Operating Systems Principles. October 1967)
- R. A. Scantlebury, P. T. Wilkinson, and K. A. Bartlett, The design of a message switching Centre for a digital communication network (IFIP 1968)
- Lawrence Roberts, The Evolution of Packet Switching (Proceedings of the IEEE, November, 1978)
- Abbate, Janet (2000), Inventing the Internet, MIT Press, ISBN 9780262511155
- Hafner, Katie Where Wizards Stay Up Late (Simon and Schuster, 1996) pp 52–67
- Norberg, Arthur; O'Neill, Judy E. Transforming Computer Technology: Information Processing for the Pentagon, 1962-1982 (Johns Hopkins University, 1996)
- Wilkinson, Peter (Summer 2020), "Packet Switching and the NPL Network", Computer Resurrection: The Journal of the Computer Conservation Society (90), ISSN 0958-7403CS1 maint: date and year (link)
- Oral history interview with Paul Baran. Charles Babbage Institute University of Minnesota, Minneapolis. Baran describes his working environment at RAND, as well as his initial interest in survivable communications, and the evolution, writing and distribution of his eleven-volume work, "On Distributed Communications". Baran discusses his interaction with the group at ARPA who were responsible for the later development of the ARPANET.
- NPL Data Communications Network NPL video, 1970s
- Packet Switching History and Design, site reviewed by Baran, Roberts, and Kleinrock
- Paul Baran and the Origins of the Internet
- 20+ articles on packet switching in the 1970s
- "An Introduction to Packet Switched Networks", Phrack, 05/3/88