The International Network Working Group (INWG) was a group of prominent

computer science Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, ...

researchers in the 1970s who studied and developed standards and protocols for interconnection of

computer network A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or b ...

s. 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 Internetworking is the practice of interconnecting multiple computer networks. Typically, this enables any pair of hosts in the connected networks to exchange messages irrespective of their hardware-level networking technology. The resulting sys ...

. INWG became a subcommittee of the

International Federation for Information Processing The International Federation for Information Processing (IFIP) is a global organisation for researchers and professionals working in the field of computing to conduct research, develop standards and promote information sharing. Established in 19 ...

(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 The Transmission Control Protocol (TCP) is one of the main communications protocol, protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, th ...

and

Internet Protocol The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP ...

(TCP/IP) that emerged later.

History

Founding and IFIP affiliation

The International Network Working Group was formed by Steve Crocker,

Louis Pouzin Louis Pouzin (born 20 April 1931) is a French computer scientist and Internet pioneer. He directed the development of the CYCLADES computer network in France the early 1970s, which implemented a novel design for packet communication. He was the ...

, Donald Davies, and Peter Kirstein in June 1972 in Paris at a networking conference organised by Pouzin. Crocker saw that it would be useful to have an international version of the Network Working Group, which developed the Network Control Program for the

ARPANET 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 tec ...

. At the International Conference on Computer Communication (ICCC) in Washington D.C. in October 1972, Vint Cerf was approved as INWG's Chair on Crocker's recommendation. The group included American researchers representing the ARPANET and the Merit network, the French

CYCLADES 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 i ...

and RCP networks, and British teams working on the NPL network, EPSS, and

European Informatics Network In telecommunications, packet switching is a method of grouping data into short messages in fixed format, i.e. '' packets,'' that are transmitted over a digital network. Packets consist of a header and a payload. Data in the header is used b ...

. During early 1973, Pouzin arranged affiliation with the

(IFIP). INWG became IFIP Working Group 1 under Technical Committee 6 (Data Communication) with the title "International Packet Switching for Computer Sharing" (WG6.1). This standing, although informal, enabled the group to provide technical input on packet networking to CCITT and

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

. Its purpose was to study and develop "international standard protocols for internetworking". INWG published a series numbered notes, some of which were also RfCs.

Gateways/routers

The idea for a router (called a '' gateway'' at the time) initially came about through INWG. These gateway devices were different from most previous packet switching schemes in two ways. First, they connected dissimilar kinds of networks, such as serial lines and

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, campus, or building, and has its network equipment and interconnects locally managed. LANs facilitate the distribution of da ...

s. Second, they were connectionless devices, which had no role in assuring that traffic was delivered reliably, leaving that function entirely to the hosts. This particular idea, the end-to-end principle, had been pioneered in the CYCLADES network.

Proposal for an international end-to-end protocol

INWG met in New York in June 1973. Attendees included Cerf, Bob Kahn, Alex McKenzie, Bob Metcalfe, Roger Scantlebury, John Shoch and Hubert Zimmermann, among others. They discussed a first draft of an ''International Transmission Protocol'' (ITP). Zimmermann and Metcalfe dominated the discussions; Zimmermann had been working with Pouzin on the CYCLADES network while Metclafe, Shoch and others at Xerox PARC had been developing the idea of

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

and the PARC Universal Packet (PUP) for internetworking. Notes from the meetings were recorded by Cerf and McKenzie, which was circulated after the meeting (INWG 28). There was a follow-up meeting in July. Gerard LeLann and G. Grossman made contributions after the June meeting. Building on this work, in September 1973, Kahn and Cerf presented a paper, ''Host and Process Level Protocols for Internetwork Communication,'' at the next INWG meeting at the

University of Sussex The University of Sussex is a public university, public research university, research university located in Falmer, East Sussex, England. It lies mostly within the city boundaries of Brighton and Hove. Its large campus site is surrounded by the ...

in England (INWG 39). Their ideas were refined further in long discussions with Davies, Scantlebury, Pouzin and Zimmerman. Pouzin circulated a paper on ''Interconnection of Packet Switching Networks'' in October 1973 (INWG 42), in which he introduced the term '' catenet'' for an interconnected network. Zimmerman and Michel Elie wrote a ''Proposed Standard Host-Host Protocol for Heterogenous Computer Networks: Transport Protocol'' in December 1973 (INWG 43). Pouzin updated his paper with ''A Proposal for Interconnecting Packet Switching Networks'' in March 1974 (INWG 60), published two months later in May. Zimmerman and Elie circulated a ''Standard host-host protocol for heterogeneous computer networks'' in April 1974 (INWG 61). Pouzin published ''An integrated approach to network protocols'' in May 1975. Kahn and Cerf published a significantly updated and refined version of their proposal in May 1974, ''A Protocol for Packet Network Intercommunication''. A later version of the paper acknowledged several people including members of INWG and attendees at the June 1973 meeting. It was updated in INWG 72/RFC 675 in December 1974 by Cerf, Yogen Dalal and Carl Sunshine, which introduced the term ''internet'' as a shorthand for ''internetwork''. INWG-arch

Two competing proposals had evolved, the early Transmission Control Program (TCP), originally proposed by Kahn and Cerf, and the CYCLADES transport station (TS) protocol, proposed by Pouzin, Zimmermann and Elie. There were two sticking points: whether there should be fragmentation of datagrams (as in TCP) or standard-sized datagrams (as in TS); and whether the data flow was an undifferentiated stream or maintained the integrity of the units sent. These were not major differences. After "hot debate", McKenzie proposed a synthesis in December 1974, ''Internetwork Host-to-Host Protocol'' (INWG 74), which he refined the following year with Cerf, Scantlebury and Zimmerman (INWG 96). After reaching agreement with the wider group, a ''Proposal for an international end to end protocol'', was published by Cerf, McKenzie, Scantlebury, and Zimmermann in 1976. It was presented to the CCITT and ISO by Derek Barber, who became INWG chair earlier that year. Although the protocol was adopted by networks in Europe, it was not adopted by the CCITT, ISO nor the ARPANET. The CCITT went on to adopt the

X.25 X.25 is an ITU-T standard protocol suite for Packet switched network, packet-switched data communication in wide area network, wide area networks (WAN). It was originally defined by the CCITT, International Telegraph and Telephone Consultative Co ...

standard in 1976, based on

virtual circuit A virtual circuit (VC) is a means of transporting data over a data network, based on packet switching and in which a connection is first established across the network between two endpoints. The network, rather than having a fixed data rate reser ...

s. ARPA began testing TCP in 1975 at Stanford, BBN and University College London. Ultimately, ARPA developed the

Internet protocol suite The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are ...

, including the

as connectionless layer and the

as a reliable connection-oriented service, which reflects concepts in Pouzin's CYCLADES project.

Email

Ray Tomlinson is well known as the creator of network mail (i.e.,

email Electronic mail (usually shortened to email; alternatively hyphenated e-mail) is a method of transmitting and receiving Digital media, digital messages using electronics, electronic devices over a computer network. It was conceived in the ...

) in INWG Protocol note 2 (a separate series of INWG notes), in September 1974. Derek Barber proposed an electronic mail protocol in 1979 in INWG 192 and implemented it on the European Informatics Network. This was referenced by Jon Postel in his early work on Internet email, published in the Internet Experiment Note series.

Later

Alex McKenzie served as chair from 1979-1982 and Secretary beginning in 1983. Carl Sunshine, who had worked with Vint Cerf and Yogen Dalal at Stanford on the first TCP specification, subsequently served as INWG chair until 1987, when Harry Rudin took over. Later international work led to the

OSI model The Open Systems Interconnection (OSI) model is a reference model developed by the International Organization for Standardization (ISO) that "provides a common basis for the coordination of standards development for the purpose of systems inter ...

in 1984, of which many members of the INWG became advocates. During the '' Protocol Wars'' of the late 1980s and early 1990s, engineers, organizations and nations became polarized over the issue of which standard, the OSI model or the Internet protocol suite would result in the best and most robust computer networks. ARPA partnerships with the telecommunication and computer industry led to widespread private sector adoption of the Internet protocol suite as a communication protocol. The INWG continued to work on protocol design and formal specification until the 1990s when it disbanded as the

Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...

grew rapidly. Nonetheless, issues with the Internet Protocol suite remain and alternatives have been proposed building on INWG ideas such as Recursive Internetwork Architecture.

Legacy

The work of INWG was a significant step in the creation of the Transmission Control Program and ultimately the Internet.

Members

The group had about 100 members, including the following: * Derek Barber * B. Barker * Vint Cerf * W. Clipsham * Donald Davies * Rémi Despres * V. Detwiler * Frank Heart * Alex McKenzie * Louis Pouzin * O. Riml * Harry Rudin * K. Samuelson * K. Sandum * Roger Scantlebury * B. Sexton * P. Shanks * C.D. Shepard * Carl Sunshine * J. Tucker * Barry Wessler * Hubert Zimmerman

Notes

References

Primary sources

In chronological order: * Cerf, Vinton (editor) (June 1973), ''International Transmission Protocol'', IFIP WG6.1, INWG 28. * Cerf, Vinton; Kahn, Robert (September 1973), ''Host and Process Level Protocols for Internetwork Communication'', IFIP WG6.1, INWG 39. * Pouzin, Louis (October 1973), ''Interconnection of Packet Switching Networks'', IFIP WG6.1, INWG 42. * Zimmermann, Hubert; Elie, Michel (December 1973), ''Proposed Standard Host-Host Protocol for Heterogenous Computer Networks: Transport Protocol'', IFIP WG6.1, INWG 43. * Pouzin, Louis (March 1974), ''A Proposal for Interconnecting Packet Switching Networks'', IFIP WG6.1, INWG 60. * Zimmermann, Hubert; Elie, Michel (April 1974), ''Transport Protocol: Standard Host-Host Protocol for Heterogeneous Computer Networks'', IFIP WG6.1, INWG 61. * * Pouzin, Louis (May 1974), ''A Proposal for Interconnecting Packet Switching Networks'', Proceedings of EUROCOMP, Brunel University, pp. 1023-36. * McKenzie, Alex (December 1974), ''Internetwork Host-to-Host Protocol'', IFIP WG6.1, INWG 74. * * Cerf, Vinton; McKenzie, Alex; Scantlebury, Roger; Zimmermann, Hubert (July 1975), ''Proposal for an Internetwork End-to-End Protocol'', IFIP WG6.1, INWG 96. *

External links

International Packet Network Working Group (INWG)
Charles Babbage Institute Archives, University of Minnesota Archival Collection Communications protocols Network protocols