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Network Working Group                                            K. OwenRequest for Comments:  828                                          IFIP                                                             August 1982DATA COMMUNICATIONS:  IFIP'S INTERNATIONAL "NETWORK" OF EXPERTS     (This report has been written for IFIP by Kenneth Owen, former                Technology Editor of The Times, London)[ This RFC is distributed to inform the ARPA Internet community of theactivities of the IFIP technical committee on Data Communications, andto encourage participation in those activities. ]A vital common thread which runs through virtually all current advancesin implementing and operating computer-based systems is that of datacommunications.  The interconnection of the various elements of completesystems in new ways has become the driving force behind a substantialresearch and development effort.In both national and international systems, a variety of new options hasbeen opening up in recent years.  Increasingly the development of thesenew systems involves people and groups from a variety ofbackgrounds--the computer industry, the telecommunications industry, thenational telecommunications authorities and the national andinternational standards bodies.In an area where the formerly distinct technologies of computing andtelecommunications have so clearly converged, the new technologypresents both opportunities and problems.  And this convergence oftechnologies demands an "interconnection" also between the variousgroups mentioned above.For different purposes, and in different parts of the world, thespecific technological solutions will vary, though drawing on the samebasic research and development.  Global, regional, national and localsystems are all involved.  Systems are being designed at a time when thetechnology itself is continuing to advance rapidly and there are manyuncertainties in choosing the best directions fo follow.  Nonetheless,international standards must be developed and agreed.This background -- of interacting elements of a complex, rapidlyadvancing technology -- lies behind the work of Technical Committee 6(TC 6) of the International Federation for Information Processing(IFIP).  IFIP's membership consists of the appropriate nationalprofessional organizations, one per country, and its aims include thepromotion of information science and technology and the advancement ofinternational cooperation in this field.The broad field of information processing is subdivided for IFIPpurposes into a number of specialist areas, each of which is covered by                                   1

RFC 828                                                      August 1982one of the Federation's technical committees.  TC 6 aims to promote theexchange of information about data communication; to bridge some of thegaps that exist between users, telecommunications administrations andthe manufactures of computers and equipment; and to cultivate workingcontacts with other relevant international bodies.Chairman of the committee is Professor Andre Danthine of the Universityof Liege, Belgium.  "The main interest of TC 6", he says, "is to have areal exchange of technical information, on an international basis, intwo ways which are completely intermixed."  In essence these two aspectsreflect the respective needs of people in the developed and thedeveloping nations.In the developed countries where the technology is advancing mostrapidly, the basic need is for a full information exchange between theresearchers and the professional practitioners.  The research willinclude work which draws on voice and video communication; and thepractitioners will come from the traditional computer andtelecommunications industries (now competing with each other in thisarea) and from the new "telematics" industry.This interchange of ideas between experts in the developed nations iscomplemented by the second category of the work of TC 6:  theinterchange of information with the developing countries.  "One of mymain objectives as a technical committee chairman", says ProfessorDanthine, "is to try to keep a balance between meeting the needs of theexpert, and the responsibility of the expert to explain the state of theart to people in the developing nations."These "state of the art" or review conferences are an important part ofthe TC 6 programme.  Each of IFIP's technical committees is made up ofnational representatives (plus working group chairmen, whose work isdescribed later in this article); and the strength of the TC 6membership is such that, when necessary, the committee can mountcomprehensive "state of the art" conference programmes with speakersdrawn from its own ranks.  In this role the committee is a technical"travelling circus" -- one in which, as for IFIP activities generally,the performers receive no fees.The technical committee plans its overall programme of events and actsas the driving mechanism for the TC 6 activity, Professor Danthine pontsout, but the programme is normally implemented by the committee'svarious specialist working groups as appropriate.  The TC 6 workinggroups are not small subcommittees in the conventional sense of theterm; each is a specialist community of perhaps 200 people who keep intouch by mail (including electronic mail).The working groups embrace a range of activities.  First, there is the                                   2

RFC 828                                                      August 1982basic, routine process of information dissemination between members.Each working group has a distribution system by which papers, reportsand notes can be "broadcast" to the group membership.  This is muchwider in scope and more flexible than the mechanism of meetings; it canbe used to report research results, for example, prior to formalpublication.Secondly, the working groups hold informal discussion "workshops" atwhich a particular group of specialists will try to work towards aconsensus.  Often timed to take place at a very early stage in thedevelopment of a significant new technique or area of interest, thesemeetings attempt to clarify the relevant terminology and methodologythat will be needed in moving towards a full understanding of thesubject area.A third activity is to hold relatively small "working conferences" -- anIFIP term which defines a meeting of invited experts, at which eachparticipant presents a formal paper.  The proceedings are subsequentlypublished to disseminate the results to the scientific world in general.To gain a wider interaction than is possible at a working conference,TC 6 pursues a fourth type of information exchange, that of the"in-depth symposium".  This, as its name implies, is a highly technicalopen conference on a well-defined topical subject, designed to attractas large an attendance as possible.  For TC 6 the in-depth symposium isan annual event.Professor Danthine stresses the broad range of technology and ofinterests that is represented on his technical committee.  And hestresses that it is technology rather than science that interests hismembers."We have very few people engaged in pure research in the sense thattheir work is not application-oriented.  Even those who work in protocolverification have some application in mind.  They try to find formalmethods in a way which may be characterized as basic applied research.On the other hand, when advances are happening rapidly in computerscience, something which is theoretical becomes useful very quickly."                                   3

RFC 828                                                      August 1982LOCAL NETWORKSWithin data communications, no subject has aroused more general interestin recent years than that of local computer networks, triggered by theradical possibilities opened up by the Xerox Ethernet system.  WithinTC 6, the subject of local computer networks is addressed by workinggroup WG 6.4, chaired by Greg Hopkins of Ungerman-Bass (while RobertMetcalfe, inventor of Ethernet, is the United States representative onthe technical committee).Local networks show all the signs of being a "bandwagon" subject at thepresent time, with many people and organizations running to jump aboard.The concept is not new; local networks were implemented in Canada, theUnited States and Britain in the 1960s.  But the appearance of Ethernetstarted the bandwagon rolling.  The message of Ethernet basically wasthat new kinds of network structure existed, quite different from thoseof large-area networks, which were appropriate to very high speeds oftransmission and rather limited geographical areas; and that by usingthese high-speed networks one could reorganize the way that oneinterconnected all parts of a computing system in a particular ofice, orlaboratory, or factory.The aims of WG 6.4 are "to organize interest and promote the exchange ofinformation on networks of locally distributed digital computers" and"to develop recommendations for international standardization of localcomputer networking technology".  A good example of what this means inpractice was the international symposium on local computer networks,organized by WG 6.4 for TC 6, which attracted more than 500 delegates toFlorence earlier this year.This was TC 6's "in-depth" event for 1982, covering such topics as VLSItechniques, network reliability, voice distribution, LCN design andapplications, performance evaluation, protocols, gateways and standards.Aspects of Ethernet, "slotted" ring networks such as the Cambridge Ring,and "token" rings (pioneered in Canada in the mid-1960s and now thesubject of renewed interest) were discussed in detail.  One of theinteresting developments reported at Florence concerned work on anadvanced token ring at IBM's research laboratories at Ruschlikon,Zurich, Switzerland.The relative characteristics of the Ethernet and ring categories oflocal networks are still very much a matter for technical debate.  Andthe so-called broadband networks are a third competing category;carrying far more information (at the cost of losing some logicalsimplicity), they offer the prospect of combining cable television withinteractive computer-based services.Thus the present time is one of intense marketing activity by the                                   4

RFC 828                                                      August 1982proponents of the respective technologies--and so a time when thefullest international exchange of information on technical developmentsis particularly important.As interpreted by WG 6.4 local computer networks are "local" in thatthey are concerned with communication over distances between ten metresand 10,000 metres.  Their "computers" are the devices which require andprovide the transmission of data in terminals and in large centralprocessing systems.The "networks" may employ a variety of transmission media, includingtwisted pairs, coaxial cable, fibre optics and local radio.  Those ofmost interest to WG 6.4 will use data rates above 100 kilobits persecond.  Among the major topics tackled by the group are the role ofprotocols in local computer networks and the interconnection of localcomputer networks with remote networks.MESSAGINGInternational computer message systems and services form another rapidlydeveloping topic, Messages may be processed, stored and transmittedbetween users who may be within the jurisdiction of separate carriers,computer systems and/or computer networks.  Technical, economic andpolitical issues must be resolved if a viable international computermessage service is to develop.  Within TC 6, this is the concern ofworking group WG 6.5, chaired by Ronald Uhlig of Bell-Northern Research,Ottawa, Canada.This working group concentrates on standards for data structures,addressing, and higher-level protocols to effect internatioanalcomputer-mediated message services, Such services could have an impacton existing international postal and communication agreements, and onthe economics of the worldwide communication system.  Results of thegroup's work are made available to users, manufacturers, commoncarriers, PTTs, ISO and CCITT.One of the most comprehensive moves by TC 6 and WG 6.5 to influence thedevelopment of international computer-based message services was thepublication of a set of policy recommendations which came out of aworking-group workshop in Bonn in 1980 and was confirmed by thetechnical committee.  These concerned the right to operate suchservices; restrictions on transborder data flow; and tariff issues.Organizations should be free to operate their own computer-based messageservices and to interconnect these services for messages betweenorganizations through public networks, TC 6 stated.  (The aim here wasto preserve the basic freedom to communicate without entering into the                                   5

RFC 828                                                      August 1982more controversial subject of third-party traffic, which is regardeddifferently in different countries.)No restriction should be placed on the transmission across borders ofmessages between persons.  If restrictions were placed on the nature ofcomputer-based messages transmitted across a country's borders (theforbidding of encipherment, for example), then the conditions should notbe more severe than those placed on letter post.  (It was appreciatedthat restrictions on the flow of data across borders could be regardedas necessary to prevent the circumvention of national privacy laws bythe use of databases abroad but, the committee argued, the remedy shouldbe to rationalize the data privacy laws, not to restrict the data flow.)On tarriff principles, TC 6 recommended that tariff levels should notdiscriminate against computer-based message services, whether public orprivate; there should be no heavy extra charge for internationalmessages; the principles of charging should not discourage the sensible,expected pattern of usage; and charges for preparation and sending ofmessages should be separated.  (Here the background danger was thatpublic-service tariffs might be manipulated to achieve unfairobjectives, such as discouraging the use of new services or exploiting amonopoly.)Policy aspects such as these represent one of three main themes whichare pursued within WG 6.5 in a formal structure of sub-groups.  Theother two themes are the systems environment (overall systems issues ofcomputer messaging) and the user environment (the user interface and allother aspects of user involvement).  European and North Americansub-groups work in parallel in each of these two subject areas."We started out with the realization that computer messge systems werecoming along very rapidly, with many different systems appearing indifferent parts of the world, and we could see the day coming whenpeople wree going to want all these systems to talk to each other", saysRonald Uhlig.  "That wasn't going to happen unless we started to getpeople together.  The first ones of the type we're talking about were onthe Arpanet in the United States.  For TC 6, computer messaging was thesubject of the 1981 in-depth symposium which was held in Ottawa."An important concept of mail messaging has emerged from WG 6.5's work onsystems environment.  This divides computer messages from the systemspoint of view into two parts, known respectively as the message transferagent and the user agent.The user agent acts on behalf of the individual user.  When the userwishes to send a message he initially enters the user agent function.The "agent" is probably software, but the concept is broad.  The useragent might be in a terminal, in a concentrator, in a PBX or in the                                   6

RFC 828                                                      August 1982network.  It interacts with the user and handles everything up to thepoint of composing the message.The user then gives the user agent instructions to send the message.  Atthat point the message is in effect placed inside an electronicenvelope, and "posted" to a message transfer agent.  The message maypass from one messge transfer agent to another before finally passing tothe receiving user agent which handles functions concerned with readingthe message, filing it, etc.The work of WG 6.5's systems environment group led to the formalconsideration of message-handling standards by a study group of CCITT.The CCITT group is concentrating at present on devising standards fo theprotocols for the transfer of messages between message transfer agents."Once that becomes standardized", says Ronald Uhlig, "you've taken amajor step towards allowing anybody's message system to communicate withanybody else's.  Next we want to concentrate on obtaining some consensusfor standards on compatible sets of functions in user agents.  You canhave many different kinds of user agents--those which will accept onlytext messages, or voice messages, for example."Another important development within WG 6.5 which is just getting underway is concerned with messaging for developing nations.  Here there aretwo dimensions -- national and international.  The international problemis how to enable scientists (and in particular computer scientists) inthe developing nations to keep in touch with their colleagues in themore advanced countries.  An international message system could be thesolution.Within individual developing countries there is the possibility of usingcomputer-based messaging as a superior type of internal telegramservice.  People sending telegrams would go to a local post office todictate their messages.  Post offices would be linked in a messagesystem, and at the receiving office the message would be printed out andthen hand-delivered.Dr. S. Ramani of India and Professor Liane Tarouco of Brazil areco-chairmen of WG 6.5's new subgroup on messaging for developingnations.  Dr. Ramani has suggested that India might launch a smallsatellite into a relatively low earth orbit, to be used for thetransmission of messages within developing countries (and possiblyinternationally).Another subgroup within WG 6.5, it has been suggested, might be formedto discuss messaging for the hearing impaired.  This has been approvedin principle, but has not yet generated sufficient active interest forit to move ahead.                                   7

RFC 828                                                      August 1982Thus working groups 6.4 and 6.5 have an active, continuing programme inwell-defined subject areas.  TC 6's other two working groups, 6.1 and6.3, are each in a state of flux at present as they review their scopein order to respond to changing needs.PROTOCOLSWG 6.1 has been concerned up to now with "international packet switchingfor computer sharing".  Formed in 1973 from the nucleus of an existingnon-IFIP international network working group (which itself had grown outof a United States network working group within the Arpanet community),it played a key role in the development of communication protocols forcomputer networks.The working group defined its original scope as follows.  The groupwould study the problems of the interworking of packet-switched computernetworks planned in various countries.  The group's ultimate goal was todefine the technical characteristics of facilities and operatingprocedures which would make it possible and attractive to interconnectsuch networks.  In pursuit of this goal, the group would attempt todefine and publish guidelines for the interconnection ofpacket-switching networks.  Where possible, it would test the guidelineswith experimental interconnections between cooperating networks.Thus, the mainstream of WG 6.1 activity has been in the area ofprotocols, an area where the emphasis has now shifted from theinvestigative research and discussion of IFIP to the follow-on work ofthe international standards bodies.  In 1978 an in-depth symposium oncomputer network protocols was held in Liege.  In 1979 an in-depthsymposium on flow control in complex data networks was held in Paris;the subject of flow control and overall network design is now regardedas having largely moved out of the research area and into the area ofcommercial exploitation.  In 1981 a workshop on formal description andverification techniques was held at the National Physical Laboratory,Teddington, England.For the outside scientific community, WG 6.1 has thus been the focus forsignificant research and information exchange.  Within TC 6 it has alsoplayed a significant role as the parent of subgroups which have gone onto develop into working groups in their own right.  For the future, itis the intention that WG 6.1 should continue this latter "umbrella"role, probably under a general "architecture and protocols for networks"title, with specific new areas being hived off into subgroups asappropriate.One such subgroup of the new 6.1 could well be concerned with satellitesystems.  At first sight it might appear a little late for a group suchas TC 6 to begin to turn its attention to an established communication                                   8

RFC 828                                                      August 1982medium such as satellite systems, but the committee has in mindsignificant new variations on the satellite theme."Satellites have been used up to now almost entirely to providetelephone channels", says Dr. Donald Davies of the National PhysicalLaboratory, England, who is the recently elected vice-chairman of TC 6."What we want to do now is to develop satellite systems that will mixvoice and vision and data in such a way as to get the most use out ofthe channel.  You can very often get the best use of the channel bymixing different types of traffic in this way.  But you get theseadvantages only if you're prepared to design the multiplexing systemaround the requirements."Satellite Business Systems does this already to a certain extent.  ButI believe that new types of multiplexing schemes will be developed forsatellites which will make the future generation of mixed-mediasatellites much more powerful.""Then there's the question:  if you do have a satellite systemintegrated with a surface network, and then perhaps with a number oflocal networks, how do you set up the hierarchy of protocols to connectall that together, in a way that actually works conveniently?  That's anunsolved problem.""We know how to make a satellite into a sort of substitute telephoneline, but what we don't know is how to make one of these rather moreintelligent satellite systems work in nicely with the local network.That's one of the functions of the Universe project in the UK."Another possible new topic which could come under the WG 6.1 umbrella isthat of data security, which is the area of research in which Dr. Daviesis working at NPL.  It presents a difficult technical problem, the needfor standards, and above all a need to anaylze the user's requirements.Dr. Davies points out that ring networks, Ethernet systems and satellitesystems all use broadcast transmissions, with obvious dangers of datainsecurity.HUMAN FACTORSWorking Group 6.3, whose title is "Human-computer interaction", is alsobeing reviewed at present for rather different reasons.  The group wasformed in 1975, re-formed in 1981, and has been concerned withdeveloping a science and technology of the interaction between peopleand computers.  It was concerned in particular with computer users,especially those who were not computer professionals, and with how toimprove the human-computer relationship for them.Identified areas for study included the problems people have with                                   9

RFC 828                                                      August 1982computers; the impact of computers on individuals and organizations; thedeterminants of utility, usability and acceptability; the appropriateallocation of tasks between computers and people; modelling the user asan aid to better system design; and harmonizing the computer to thecharacteristics and needs of the user.Clearly the scope of 6.3 was deliberately set wide, with a tendencytowards general principles rather than particular systems.  But it wasrecognized that progress would be achieved only through specific studieson practical issues--for example, on interface design standards, commandlanguage consistency, documentation, appropriateness of alternativecommunication media and human factors guidelines for dialogue design.Chairman of WG 6.3 in recent years has been Professor Brian Shackel ofLoughborough University of Technology, UK, who played the leading rolein re-forming the group in 1981.The scope of 6.3 in fact goes beyond the scope of any single technicalcommittee.  It is close to that of TC 9, for example, whose subject isthe relationship between computers and society; and of TC 8, which isconcerned with information systems.  Activities which cut acrossboundaries in this way can be organized jointly by working groups from anumber of TCs, but in the case of WG 6.3 the future status of the groupis now the subject of an ad hoc review.THE FUTURELooking ahead, Professor Danthine sums up:  "I think that the mostimportant developments that are ahead of us will involve local networks,the digital PBX, and the concept of the Integrated Services DigitalNetwork (ISDN).  It will be interesting to see what will finally comeout of the various pressures, coming from different directions, for thesame market.  Some of the directions are technology-driven; some aremarketing-driven.  It is not at all clear what will happen."The role of TC 6 -- or rather the working groups -- is to act as aforum where experts can advocate, and assess, the various alternatives.We do not restrict ourselves to the view of any one sector -- thetelecommunications authorities, say, or the manufacturers.  We are muchmore open-minded, and exposed to the opinions of people who are notnecessarily from our own domain of work."One area in which TC 6 is seeking a fuller methodology and understandingis that of office automation.  "It is surprising to see that, at thepresent time, we are only at the beginning of a real understanding ofoffice work," says Professor Danthine, "We have no model."Thus, following the modelling work which TC 6 did in protocols, systemarchitectures and messaging systems, the committee chairman says, "we                                   10

RFC 828                                                      August 1982are now doing some modelling work in terms of office automation, inorder to understand what the problems are.  Very often a solutionappears for a problem which is not understood -- that is, not completelydefined.  That happens more often than you might think in computerscience."The next two years will be important ones for data communication:  1983is World Communication Year, and 1984 will be important because of theCCITT Integrated Services Digital Network standards which are expectedto be announced then.  These standards will indicate thetelecommunication authorities' plans for their own "local networks" (bywhich they mean the distribution systems at local level from thetelephone exchange out to the homes, offices and factories).At present this local distribution is by multicore cable.  In future itwill be by glass fibres coupled with complex electronics at the variousnodes.  At the moment nobody knows what these nodes will look like, norwhat the actual mode of transmission will be.  If the CCITT standardsare announced in 1984 they will affect everybody concerned with "localnetworks" in the computing sense.  They will influence the design of thelocal computer networks of the late eighties.These various threads of development in data communication are reflectedin TC 6's programme of meetings for 1982-85.  Planned events include aninternational conference on data communications (a "state of the art"review) in Johannesburg, South Africa, in September 1982; a workingconference on interconnected personal computing systems in Tromso,Norway, in 1983; an in-depth symposium on satellite and computercommunications in Paris, France, in 1983; and a working conference ondata communications in ISDN in Israel in 1985.  TC 6 is also active inproviding speakers for the sixth International Conference on ComputerCommunication (ICCC '82)  in September 1982 in London, England.------------------------------------------------------------------------Published by the IFIP Secretariat, 3 rue du Marche, CH-1204GENEVA,Switzerland, August 1982.For further information, please contact your National Computer Societyor the IFIP Secretariat.                                   11