Network Working Group                                            V. Cerf
Request for Comments: 1167                                          CNRI
                                                               July 1990


Status of this Memo

   The memo provides a brief outline of a National Research and
   Education Network (NREN).  This memo provides information for the
   Internet community.  It does not specify any standard.  It is not a
   statement of IAB policy or recommendations.

   Distribution of this memo is unlimited.


   This contribution seeks to outline and call attention to some of the
   major factors which will influence the form and structure of a
   National Research and Education Network (NREN).  It is implicitly
   assumed that the system will emerge from the existing Internet.


   The author gratefully acknowledges support from the National Science
   Foundation, The Defense Advanced Research Projects Agency, the
   Department of Energy and the National Aeronautics and Space
   Administration through cooperative agreement NCR-8820945.  The author
   also acknowledges helpful comments from colleagues Ira Richer, Barry
   Leiner, Hans-Werner Braun and Robert Kahn.  The opinions expressed in
   this paper are the personal opinions of the author and do not
   represent positions of the U.S. Government, the Corporation for
   National Research Initiatives or of the Internet Activities Board.
   In fact, the author isn't sure he agrees with everything in the
   paper, either!


   The expression "national research and education network" is taken to
   mean "the U.S. National Research and Education Network" in the
   material which follows.  It is implicitly assumed that similar
   initiatives may arise in other countries and that a kind of Global
   Research and Education Network may arise out of the existing
   international Internet system.  However, the primary focus of this
   paper is on developments in the U.S.

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RFC 1167                          NREN                         July 1990


   1. The NREN in the U.S. will evolve from the existing Internet base.
   By implication, the U.S. NREN will have to fit into an international
   environment consisting of a good many networks sponsored or owned and
   operated by non-U.S. organizations around the world.

   2. There will continue to be special-purpose and mission-oriented
   networks sponsored by the U.S. Government which will need to link
   with, if not directly support, the NREN.

   3. The basic technical networking architecture of the system will
   include local area networks, metropolitan, regional and wide-area
   networks.  Some nets will be organized to support transit traffic and
   others will be strictly parasitic.

   4. Looking towards the end of the decade, some of the networks may be
   mobile (digital, cellular).  A variety of technologies may be used,
   including, but not limited to, high speed Fiber Data Distribution
   Interface (FDDI) nets, Distributed-Queue Dual Bus (DQDB) nets,
   Broadband Integrated Services Digital Networks (B-ISDN) utilizing
   Asynchronous Transfer Mode (ATM) switching fabrics as well as
   conventional Token Ring, Ethernet and other IEEE 802.X technology.
   Narrowband ISDN and X.25 packet switching technology network services
   are also likely play a role along with Switched Multi-megabit Data
   Service (SMDS) provided by telecommunications carriers.  It also
   would be fair to ask what role FTS-2000 might play in the system, at
   least in support of government access to the NREN, and possibly in
   support of national agency network facilities.

   5. The protocol architecture of the system will continue to exhibit a
   layered structure although the layering may vary from the present-day
   Internet and planned Open Systems Interconnection structures in some

   6. The system will include servers of varying kinds required to
   support the general operation of the system (for example, network
   management facilities, name servers of various types, email, database
   and other kinds of information servers, multicast routers,
   cryptographic certificate servers) and collaboration support tools
   including video/teleconferencing systems and other "groupware"
   facilities.  Accounting and access control mechanisms will be

   7. The system will support multiple protocols on an end to end basis.
   At the least, full TCP/IP and OSI protocol stacks will be supported.
   Dealing with Connectionless and Connection-Oriented Network Services
   in the OSI area is an open issue (transport service bridges and

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RFC 1167                          NREN                         July 1990

   application level gateways are two possibilities).

   8. Provision must be made for experimental research in networking to
   support the continued technical evolution of the system.  The NREN
   can no more be a static, rigid system than the Internet has been
   since its inception.  Interconnection of experimental facilities with
   the operational NREN must be supported.

   9. The architecture must accommodate the use of commercial services,
   private and Government-sponsored networks in the NREN system.

   Apart from the considerations listed above, it is also helpful to
   consider the constituencies and stakeholders who have a role to play
   in the use of, provision of and evolution of NREN services.  Their
   interests will affect the architecture of the NREN and the course of
   its creation and evolution.


   The Users

      Extrapolating from the present Internet, the users of the system
      will be diverse.  By legislative intent, it will include colleges
      and universities, government research organizations (e.g.,
      research laboratories of the Departments of Defense, Energy,
      Health and Human Services, National Aeronautics and Space
      Administration), non-profit and for-profit research and
      development organizations, federally funded research and
      development centers (FFRDCs), R&D activities of private
      enterprise, library facilities of all kinds, and primary and
      secondary schools.  The system is not intended to be discipline-

      It is critical to recognize that even in the present Internet, it
      has been possible to accommodate a remarkable amalgam of private
      enterprise, academic institutions, government and military
      facilities.  Indeed, the very ability to accept such a diverse
      constituency turns on the increasing freedom of the so-called
      intermediate-level networks to accept an unrestricted set of
      users.  The growth in the size and diversity of Internet users, if
      it can be said to have been constrained at all, has been limited
      in part by usage constraints placed on the federally-sponsored
      national agency networks (e.g., NSFNET, NASA Science Internet,
      Energy Sciences Net, High Energy Physics Net, the recently
      deceased ARPANET, Defense Research Internet, etc.).  Given the
      purposes of these networks and the fiduciary responsibilities of
      the agencies that have created them, such usage constraints seem
      highly appropriate.  It may be beneficial to search for less

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RFC 1167                          NREN                         July 1990

      constraining architectural paradigms, perhaps through the use of
      backbone facilities which are not federally-sponsored.

      The Internet does not quite serve the public in the same sense
      that the telephone network(s) do (i.e., the Internet is not a
      common carrier), although the linkages between the Internet and
      public electronic mail systems, private bulletin board systems
      such as FIDONET and commercial network services such as UUNET,
      ALTERNET and PSI, for example, make the system extremely
      accessible to a very wide variety of users.

      It will be important to keep in mind that, over time, an
      increasing number of institutional users will support local area
      networks and will want to gain access to NREN by that means.
      Individual use will continue to rely on dial-up access and, as it
      is deployed, narrow-band ISDN.  Eventually, metropolitan area
      networks and broadband ISDN facilities may be used to support
      access to NREN.  Cellular radio or other mobile communication
      technologies may also become increasingly popular as access tools.

   The Service Providers

      In its earliest stages, the Internet consisted solely of
      government-sponsored networks such as the Defense Department's
      ARPANET, Packet Radio Networks and Packet Satellite Networks.
      With the introduction of Xerox PARC's Ethernet, however, things
      began to change and privately owned and operated networks became
      an integral part of the Internet architecture.

      For a time, there was a mixture of government-sponsored backbone
      facilities and private local area networks.  With the introduction
      of the National Science Foundation NSFNET, however, the
      architecture changed again to include intermediate-level networks
      consisting of collections of commercially-produced routers and
      trunk or access lines which connected local area network
      facilities to the government-sponsored backbones.  The
      government-sponsored supercomputer centers (such as the National
      Aerospace Simulator at NASA/AMES, the Magnetic Fusion Energy
      Computing Center at Lawrence Livermore Laboratory and the half-
      dozen or so NSF-sponsored supercomputer centers) fostered the
      growth of communications networks specifically to support
      supercomputer access although, over time, these have tended to
      look more and more like general-purpose intermediate-level

      Many, but not all, of the intermediate-level networks applied for
      and received seed funding from the National Science Foundation.
      It was and continues to be NSF's position, however, that such

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RFC 1167                          NREN                         July 1990

      direct subsidies should diminish over time and that the
      intermediate networks should become self-sustaining.  To
      accomplish this objective, the intermediate-level networks have
      been turning to an increasingly diverse user constituency (see
      section above).

      The basic model of government backbones, consortium intermediate
      level nets and private local area networks has served reasonably
      well during the 1980's but it would appear that newer
      telecommunications technologies may suggest another potential
      paradigm.  As the NSFNET moves towards higher speed backbone
      operation in the 45 Mb/s range, the importance of carrier
      participation in the enterprise has increased.  The provision of
      backbone capacity at attractive rates by the inter-exchange
      carrier (in this case, MCI Communications Corporation) has been
      crucial to the feasibility of deploying such a high speed system.

      As the third phase of the NREN effort gets underway, it is
      becoming increasingly apparent that the "federally-funded
      backbone" model may and perhaps even should or must give way to a
      vision of commercially operated, gigabit speed systems to which
      the users of the NREN have access.  If there is federal subsidy in
      the new paradigm, it might come through direct provision of
      support for networking at the level of individual research grant
      or possibly through a system of institutional vouchers permitting
      and perhaps even mandating institution-wide network planning and
      provision.  This differs from the present model in which the
      backbone networks are essentially federally owned and operated or
      enjoy significant, direct federal support to the provider of the

      The importance of such a shift in service provision philosophy
      cannot be over-emphasized.  In the long run, it eliminates
      unnecessary restrictions on the use and application of the
      backbone facilities, opening up possibilities for true ubiquity of
      access and use without the need for federal control, except to the
      extent that any such services are considered in need of
      regulation, perhaps.  The same arguments might be made for the
      intermediate level systems (metropolitan and regional area access
      networks).  This does NOT mean that private networks ranging from
      local consortia to inter-continental systems will be ruled out.
      The economics of private networking may still be favorable for
      sufficiently heavy usage.  It does suggest, however, that
      achieving scale and ubiquity may largely rely on publicly
      accessible facilities.

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RFC 1167                          NREN                         July 1990

   The Vendors

      Apart from service provision, the technology available to the
      users and the service providers will come largely from commercial
      sources.  A possible exception to this may be the switches used in
      the gigabit testbed effort, but ultimately, even this technology
      will have to be provided commercially if the system is to achieve
      the scale necessary to serve as the backbone of the NREN.

      An important consequence of this observation is that the NREN
      architecture should be fashioned in such a way that it can be
      constructed from technology compatible with carrier plans and
      available from commercial telecommunications equipment suppliers.
      Examples include the use of SONET (Synchronous Optical Network)
      optical transmission technology, Switched Multimegabit Data
      Services offerings (metropolitan area networks), Asynchronous
      Transmission Mode (ATM) switches, frame relays, high speed,
      multi-protocol routers, and so on.  It is somewhat unclear what
      role the public X.25 networks will play, especially where narrow
      and broadband ISDN services are available, but it is also not
      obvious that they ought to be written off at this point.  Where
      there is still research and development activity (such as in
      network management), the network R&D community can contribute
      through experimental efforts and through participation in
      standards-making activities (e.g., ANSI, NIST, IAB/IETF, Open


   It seems clear that the current Internet and the anticipated NREN
   will have to function in a highly distributed fashion.  Given the
   diversity of service providers and the richness of the constituent
   networks (as to technology and ownership), there will have to be a
   good deal of collaboration and cooperation to make the system work.
   One can see the necessity for this, based on the existing voice
   network in the U.S.  with its local and inter-exchange carrier (IEC)
   structure.  It should be noted that in the presence of the local and
   IEC structure, it has proven possible to support private and virtual
   private networking as well.  The same needs to be true of the NREN.

   A critical element of any commercial service is accounting and
   billing.  It must be possible to identify users (billable parties,
   anyway) and to compute usage charges.  This is not to say that the
   NREN component networks must necessarily bill on the basis of usage.
   It may prove preferable to have fixed access charges which might be
   modulated by access data rate, as some of the intermediate-level
   networks have found.  It would not be surprising to find a mixture of
   charging policies in which usage charges are preferable for small

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RFC 1167                          NREN                         July 1990

   amounts of use and flat rate charges are preferred for high volume

   It will be critical to establish a forum in which operational matters
   can be debated and methods established to allow cooperative operation
   of the entire system.  A number of possibilities present themselves:
   use of the Internet Engineering Task Force as a basis, use of
   existing telecommunication carrier organizations, or possibly a
   consortium of all service providers (and private network operators?).
   Even if such an activity is initiated through federal action, it may
   be helpful, in the long run, if it eventually embraces a much wider

   Agreements are needed on the technical foundations for network
   monitoring and management, for internetwork accounting and exchange
   payments, for problem identification, tracking, escalation and
   resolution.  A framework is needed for the support of users of the
   aggregate NREN.  This suggests cooperative agreements among network
   information centers, user service and support organizations to begin
   with.  Eventually, the cost of such operations will have to be
   incorporated into the general cost of service provision.  The federal
   role, even if it acts as catalyst in the initial stages, may
   ultimately focus on the direct support of the users of the system
   which it finds it appropriate to support and subsidize (e.g., the
   research and educational users of the NREN).

   A voucher system has been proposed, in the case of the NREN, which
   would permit users to choose which NREN service provider(s) to
   engage.  The vouchers might be redeemed by the service providers in
   the same sort of way that food stamps are redeemed by supermarkets.
   Over time, the cost of the vouchers could change so that an initial
   high subsidy from the federal government would diminish until the
   utility of the vouchers vanished and decisions would be made to
   purchase telecommunications services on a pure cost/benefit basis.


   The initial technical architecture should incorporate commercial
   service provision where possible so as to avoid the creation of a
   system which is solely reliant on the federal government for its
   support and operation.  It is anticipated that a hybrid system will
   develop but, for example, it is possible that the gigabit backbone
   components of the system might be strictly commercial from the start,
   even if the lower speed components of the NREN vary from private, to
   public to federally subsidized or owned and operated.

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RFC 1167                          NREN                         July 1990


   The idea of creating a National Research and Education Network has
   captured the attention and enthusiasm of an extraordinarily broad
   collection of interested parties.  I believe this is in part a
   consequence of the remarkable range of new services and facilities
   which could be provided once the network infrastructure is in place.
   If the technology of the NREN is commercially viable, one can readily
   imagine that an economic engine of considerable proportions might
   result from the widespread accessibility of NREN-like facilities to
   business sector.

Security Considerations

   Security issues are not discussed in this memo.

Author's Address

   Vinton G. Cerf
   Corporation for National Research Initiatives
   1895 Preston White Drive, Suite 100
   Reston, VA 22091

   EMail: vcerf@NRI.Reston.VA.US

   Phone: (703) 620-8990

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