rfc1017.txt

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   In the future, the internetwork should be transparent communications
   between users and resources, and provide the additional network
   services required to make use of that communications.  A user should
   be able to access whatever resources are available just as if the
   resource is in the office.  The same high level of service should
   exist independent of which network one happens to be on.  In fact,
   one should not even be able to tell that the network is there!

   It is also important that people be able to work effectively while at
   home or when traveling.  Wherever one may happen to be, it should be



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RFC 1017          Requirements for Scientific Research       August 1987


   possible to "plug into" the internetwork and read mail, access files,
   control remote instruments, and have the same kind of environment one
   is used to at the office.

   Services to locate required facilities and take advantage of them
   must also be available on the network.  These range from the basic
   "white" and "yellow" pages, providing network locations (addresses)
   for users and capabilities, through to distributed data bases and
   computing facilities.  Eventually, this conglomeration of computers,
   workstations, networks, and other computing resources will become one
   gigantic distributed "world computer" with a very large number of
   processing nodes all over the world.

2.  NETWORK CONNECTIVITY

   By network connectivity, we mean the ability to move packets from one
   point to another.

   Note that an implicit assumption in this paper is that packet
   switched networks are the preferred technology for providing a
   scientific computer network.  This is due to the ability of such
   networks to share the available link resources to provide
   interconnection between numerous sites and their ability to
   effectively handle the "bursty" computer communication requirement.

   Note that this need not mean functional interoperability, since the
   endpoints may be using incompatible protocols.  Thus, in this
   section, we will be addressing the use of shared links and
   interconnected networks to provide a possible path.  In the next
   section, the exploitation of these paths to achieve functional
   connectivity will be addressed.

   In this section, we discuss the need for providing these network
   paths to a wide set of users and resources, and the characteristics
   of those paths.  As in other sections, this discussion is broken into
   two major categories.  The first category are those goals which we
   believe to be achievable with currently available technology and
   implementations.  The second category are those for which further
   research is required.

Near Term Objectives

   Currently, there are a large number of networks serving the
   scientific community, including Arpanet, MFEnet, SPAN, NASnet, and
   the NSFnet backbone.  While there is some loose correlation between
   the networks and the disciplines they serve, these networks are
   organized more based on Federal funding.  Furthermore, while there is
   significant interconnectivity between a number of the networks, there



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RFC 1017          Requirements for Scientific Research       August 1987


   is considerable room for more sharing of these resources.

   In the near term, therefore, there are two major requirement areas;
   providing for connectivity based on discipline and user community,
   and providing for the effective use of adequate networking resources.

Discipline Connectivity

   Scientists in a particular community/discipline need to have access
   to many common resources as well as communicate with each other.  For
   example, the quantum physics research community obtains funding from
   a number of Federal sources, but carries out its research within the
   context of a scientific discourse.  Furthermore, this discourse often
   overlaps several disciplines.  Because networks are generally
   oriented based on the source of funding, this required connectivity
   has in the past been inhibited.  NSFnet is a major step towards
   satisfying this requirement, because of its underlying philosophy of
   acting as an interconnectivity network between supercomputer centers
   and between state, regional, and therefore campus networks.  This
   move towards a set of networks that are interconnected, at least at
   the packet transport level, must be continued so that a scientist can
   obtain connectivity between his/her local computing equipment and the
   computing and other resources that are needed, independently of the
   source of funds.

   Obviously, actual use of those resources will depend on obtaining
   access permission from the appropriate controlling organization.  For
   example, use of a supercomputer will require permission and some
   allocation of computing resources.  The lack of network access should
   not, however, be the limiting factor for resource utilization.

Communication Resource Sharing

   The scientific community is always going to suffer from a lack of
   adequate communication bandwidth and connections.  There are
   requirements (e.g. graphic animation from supercomputers) that
   stretch the capabilities of even the most advanced long-haul
   networks.  In addition, as more and more scientists require
   connection into networks, the ability to provide those connections on
   a network-centric basis will become more and more difficult.

   However, the communication links (e.g. leased lines and satellite
   channels) providing the underlying topology of the various networks
   span in aggregate a very broad range of the scientific community
   sites.  If, therefore, the networks could share these links in an
   effective manner, two objectives could be achieved:

      The need to add links just to support a particular network



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RFC 1017          Requirements for Scientific Research       August 1987


      topology change would be decreased, and

      New user sites could be connected more readily.

   Existing technology (namely the DARPA-developed gateway system based
   on the Internet Protocol, IP) provides an effective method for
   accomplishing this sharing.  By using IP gateways to connect the
   various networks, and by arranging for suitable cost-sharing, the
   underlying connectivity would be greatly expanded and both of the
   above objectives achieved.

Expansion of Physical Structure

   Unfortunately, the mere interconnectivity of the various networks
   does not increase the bandwidth available.  While it may allow for
   more effective use of that available bandwidth, a sufficient number
   of links with adequate bandwidth must be provided to avoid network
   congestion.  This problem has already occurred in the Arpanet, where
   the expansion of the use of the network without a concurrent
   expansion in the trunking and topology has resulted in congestion and
   consequent degradation in performance.

   Thus, it is necessary to augment the current physical structure
   (links and switches) both by increasing the bandwidth of the current
   configuration and by adding additional links and switches where
   appropriate.

Network Engineering

   One of the major deficiencies in the current system of networks is
   the lack of overall engineering.  While each of the various networks
   generally is well supported, there is woefully little engineering of
   the overall system.  As the networks are interconnected into a larger
   system, this need will become more severe.  Examples of the areas
   where engineering is needed are:

   Topology engineering-deciding where links and switches should be
   installed or upgraded.  If the interconnection of the networks is
   achieved, this will often involve a decision as to which networks
   need to be upgraded as well as deciding where in the network those
   upgrades should take place.

   Connection Engineering-when a user site desires to be connected,
   deciding which node of which network is the best for that site,
   considering such issues as existing node locations, available
   bandwidth, and expected traffic patterns to/from that site.

   Operations and Maintenance-monitoring the operation of the overall



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RFC 1017          Requirements for Scientific Research       August 1987


   system and identifying corrective actions when failures occur.

Support of Different Types of Service

   Several different end user applications are currently in place, and
   these put different demands on the underlying structure.  For
   example, interactive remote login requires low delay, while file
   transfer requires high bandwidth.  It is important in the
   installation of additional links and switches that care be given to
   providing a mix of link characteristics.  For example, high bandwidth
   satellite channels may be appropriate to support broadcast
   applications or graphics, while low delay will be required to support
   interactive applications.

Future Goals

   Significant expansion of the underlying transport mechanisms will be
   required to support future scientific networking.  These expansions
   will be both in size and performance.

Bandwidth

   Bandwidth requirements are being driven higher by advances in
   computer technology as well as the proliferation of that technology.
   As high performance graphics workstations work cooperatively with
   supercomputers, and as real-time remote robotics and experimental
   control become a reality, the bandwidth requirements will continue to
   grow.  In addition, as the number of sites on the networks increase,
   so will the aggregate bandwidth requirement.  However, at the same
   time, the underlying bandwidth capabilities are also increasing.
   Satellite bandwidths of tens of megabits are available, and fiber
   optics technologies are providing extremely high bandwidths (in the
   range of gigabits).  It is therefore essential that the underlying
   connectivity take advantage of these advances in communications to
   increase the available end-to-end bandwidth.

Expressway Routing

   As higher levels of internet connectivity occur there will be a new
   set of problems related to lowest hop count and lowest delay routing
   metrics. The assumed internet connectivity can easily present
   situations where the highest speed, lowest delay route between two
   nodes on the same net is via a route on another network.  Consider
   two sites one either end of the country, but both on the same
   multipoint internet, where their network also is gatewayed to some
   other network with high speed transcontinental links.  The routing
   algorithms must be able to handle these situations gracefully, and
   they become of increased importance in handling global type-of-



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RFC 1017          Requirements for Scientific Research       August 1987


   service routing.

3.  NETWORK SPECIFICATIONS

    To achieve the end-to-end user functions discussed in section 2, it
    is not adequate to simply provide the underlying connectivity
    described in the previous section.  The network must provide a
    certain set of capabilities on an end-to-end basis.  In this
    section, we discuss the specifications on the network that are
    required.

Near Term Specifications

   In the near term, the requirements on the networks are two-fold.
   First is to provide those functions that will permit full
   interoperability, and second the internetwork must address the
   additional requirements that arise in the connection of networks,
   users, and resources.

Interoperability

   A first-order requirement for scientific computer networks (and
   computer networks in general) is that they be interoperable with each
   other, as discussed in the above section on connectivity.  A first