| Rfc | 1017 |
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| Title | Network requirements for scientific research: Internet task force on
scientific computing |
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| Author | B.M. Leiner |
|---|
| Date | August 1987 |
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| Format: | TXT, HTML |
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| Status: | UNKNOWN |
|---|
|
Network Working Group Barry M. Leiner
Request for Comments: 1017 RIACS
August 1987
Network Requirements for Scientific Research
Internet Task Force on Scientific Computing
STATUS OF THIS MEMO
This RFC identifies the requirements on communication networks for
supporting scientific research. It proposes some specific areas for
near term work, as well as some long term goals. This is an "idea"
paper and discussion is strongly encouraged. Distribution of this
memo is unlimited.
INTRODUCTION
Computer networks are critical to scientific research. They are
currently being used by portions of the scientific community to
support access to remote resources (such as supercomputers and data
at collaborator's sites) and collaborative work through such
facilities as electronic mail and shared databases. There is
considerable movement in the direction of providing these
capabilities to the broad scientific community in a unified manner,
as evidence by this workshop. In the future, these capabilities will
even be required in space, as the Space Station becomes a reality as
a scientific research resource.
The purpose of this paper is to identify the range of requirements
for networks that are to support scientific research. These
requirements include the basic connectivity provided by the links and
switches of the network through the basic network functions to the
user services that need to be provided to allow effective use of the
interconnected network. The paper has four sections. The first
section discusses the functions a user requires of a network. The
second section discusses the requirements for the underlying link and
node infrastructure while the third proposes a set of specifications
to achieve the functions on an end-to-end basis. The fourth section
discusses a number of network-oriented user services that are needed
in addition to the network itself. In each section, the discussion
is broken into two categories. The first addresses near term
requirements: those capabilities and functions that are needed today
and for which technology is available to perform the function. The
second category concerns long term goals: those capabilities for
which additional research is needed.
This RFC was produced by the IAB Task force a Scientific Computing,
which is chartered to investigate advanced networking requirements
that result from scientific applications. Work reported herein was
supported in part by Cooperative Agreement NCC 2-387 from the
National Aeronautics and Space Administration (NASA) to the
Universities Space Research Association (USRA).
1. NETWORK FUNCTIONS
This section addresses the functions and capabilities that networks
and particularly internetworks should be expected to support in the
near term future.
Near Term Requirements
There are many functions that are currently available to subsets of
the user community. These functions should be made available to the
broad scientific community.
User/Resource Connectivity
Undoubtedly the first order of business in networking is to provide
interconnectivity of users and the resources they need. The goal in
the near term for internetworking should be to extend the
connectivity as widely as possible, i.e. to provide ubiquitous
connectivity among users and between users and resources. Note that
the existence of a network path between sites does not necessarily
imply interoperability between communities and or resources using
non-compatible protocol suites. However, a minimal set of functions
should be provided across the entire user community, independent of
the protocol suite being used. These typically include electronic
mail at a minimum, file transfer and remote login capabilities must
also be provided.
Home Usage
One condition that could enhance current scientific computing would
be to extend to the home the same level of network support that the
scientist has available in his office environment. As network access
becomes increasingly widespread, the extension to the home will allow
the user to continue his computing at home without dramatic changes
in his work habits, based on limited access.
Charging
The scientific user should not have to worry about the costs of data
communications any more than he worries about voice communications
(his office telephone), so that data communications becomes an
integral and low-cost part of our national infrastructure. This
implies that charges for network services must NOT be volume
sensitive and must NOT be charged back to the individual. Either of
these conditions forces the user to consider network resources as
scarce and therefore requiring his individual attention to conserve
them. Such attention to extraneous details not only detracts from
the research, but fundamentally impacts the use and benefit that
networking is intended to supply. This does not require that
networking usage is free. It should be either be low enough cost
that the individual does not have to be accountable for "normal"
usage or managed in such a manner that the individual does not have
to be concerned with it on a daily basis.
Applications
Most applications, in the near term, which must be supported in an
internetwork environment are essentially extensions of current ones.
Particularly:
Electronic Mail
Electronic mail will increase in value as the extended
interconnectivity provided by internetworking provides a much
greater reachability of users.
Multimedia Mail
An enhancement to text based mail which includes capabilities
such as figures, diagrams, graphs, and digitized voice.
Multimedia Conferencing
Network conferencing is communication among multiple people
simultaneously. Conferencing may or may not be done in "real
time", that is all participants may not be required to be on-
line at the same time. The multimedia supported may include
text, voice, video, graphics, and possibly other capabilities.
File Transfer
The ability to transfer data files.
Bulk Transfer
The ability to stream large quantities of data.
Interactive Remote Login
The ability to perform remote terminal connections to hosts.
Remote Job Entry
The ability to submit batch jobs for processing to remote hosts
and receive output.
Applications which need support in the near term but are NOT
extensions of currently supported applications include:
Remote Instrument Control
This normally presumes to have a human in the "control loop".
This condition relaxes the requirements on the (inter)network
somewhat as to response times and reliability. Timing would be
presumed to be commensurate with human reactions and
reliability would not be as stringent as that required for
completely automatic control.
Remote Data Acquisition
This supports the collection of experimental data where the
experiment is remotely located from the collection center.
This requirement can only be satisfied when the bandwidth,
reliability, and predictability of network response are
sufficient. This cannot be supported in the general sense
because of the enormous bandwidth, very high reliability,
and/or guaranteed short response time required for many
experiments.
These last two requirements are especially crucial when one considers
remote experimentation such as will be performed on the Space
Station.
Capabilities
The above applications could be best supported on a network with
infinite bandwidth, zero delay, and perfect reliability.
Unfortunately, even currently feasible approximations to these levels
of capabilities can be very expensive. Therefore, it can be expected
that compromises will be made for each capability and between them,
with different balances struck between different networks. Because
of this, the user must be given an opportunity to declare which
capability or capabilities is/are of most interest-most likely
through a "type-of-service" required declaration. Some examples of
possible trade-offs: File Transport Normally requires high
reliability primarily and high bandwidth secondarily. Delay is not as
important.
Bulk Transport
Some applications such as digitized video might require high
bandwidth as the most important capability. Depending on the
application, delay would be second, and reliability of lesser
importance. Image transfers of scientific data sometimes will
invert the latter two requirements.
Interactive Traffic
This normally requires low delay as a primary consideration.
Reliability may be secondary depending on the application.
Bandwidth would usually be of least importance.
Standards
The use of standards in networking is directed toward
interoperability and availability of commercial equipment. However,
as stated earlier, full interoperability across the entire
scientific community is probably not a reasonable goal for
internetworking in the near term because of the protocol mix now
present. That is not to say, though, that the use of standards
should not be pursued on the path to full user interoperability.
Standards, in the context of near term goal support, include:
Media Exchange Standards
Would allow the interchange of equations, graphics, images, and data
bases as well as text.
Commercially Available Standards
Plug compatible, commercially available standards will allow a degree
of interoperability prior to the widespread availability of the ISO
standard protocols.
Long Term Goals
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
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
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
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
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-
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
step to accomplish this is to use IP. The use of IP will allow
individual networks built by differing agencies to combine resources
and minimize cost by avoiding the needless duplication of network
resources and their management. However, use of IP does not provide
end-to-end interoperability. There must also be compatibility of
higher level functions and protocols. At a minimum, while commonly
agreed upon standards (such as the ISO developments) are proceeding,
methods for interoperability between different protocol suites must
be developed. This would provide interoperability of certain
functions, such as file transfer, electronic mail and remote login.
The emphasis, however, should be on developing agreement within the
scientific community on use of a standard set of protocols.
Access Control
The design of the network should include adequate methods for
controlling access to the network by unauthorized personnel. This
especially includes access to network capabilities that are reachable
via the commercial phone network and public data nets. For example,
terminal servers that allow users to dial up via commercial phone
lines should have adequate authentication mechanisms in place to
prevent access by unauthorized individuals. However, it should be
noted that most hosts that are reachable via such networks are also
reachable via other "non-network" means, such as directly dialing
over commercial phone lines. The purpose of network access control
is not to insure isolation of hosts from unauthorized users, and
hosts should not expect the network itself to protect them from
"hackers".
Privacy
The network should provide protection of data that traverses it in a
way that is commensurate with the sensitivity of that data. It is
judged that the scientific requirements for privacy of data traveling
on networks does not warrant a large expenditure of resources in this
area. However, nothing in the network design should preclude the use
of link level or end-to-end encryption, or other such methods that
can be added at a later time. An example of this kind of capability
would be use of KG-84A link encryptors on MILNET or the Fig Leaf
DES-based end-to-end encryption box developed by DARPA.
Accounting
The network should provide adequate accounting procedures to track
the consumption of network resources. Accounting of network
resources is also important for the management of the network, and
particularly the management of interconnections with other networks.
Proper use of the accounting database should allow network management
personnel to determine the "flows" of data on the network, and the
identification of bottlenecks in network resources. This capability
also has secondary value in tracking down intrusions of the network,
and to provide an audit trail if malicious abuse should occur. In
addition, accounting of higher level network services (such as
terminal serving) should be kept track of for the same reasons.
Type of Service Routing
Type of service routing is necessary since not all elements of
network activity require the same resources, and the opportunities
for minimizing use of costly network resources are large. For
example, interactive traffic such as remote login requires low delay
so the network will not be a bottleneck to the user attempting to do
work. Yet the bandwidth of interactive traffic can be quite small
compared to the requirements for file transfer and mail service which
are not response time critical. Without type of service routing,
network resources must sized according to the largest user, and have
characteristics that are pleasing to the most finicky user. This has
major cost implications for the network design, as high-delay links,
such as satellite links, cannot be used for interactive traffic
despite the significant cost savings they represent over terrestrial
links. With type of service routing in place in the network
gateways, and proper software in the hosts to make use of such
capabilities, overall network performance can be enhanced, and
sizable cost savings realized. Since the IP protocol already has
provisions for such routing, such changes to existing implementations
does not require a major change in the underlying protocol
implementations.
Administration of Address Space
Local administration of network address space is essential to provide
for prompt addition of hosts to the network, and to minimize the load
on backbone network administrators. Further, a distributed name to
address translation service also has similar advantages. The DARPA
Name Domain system currently in use on the Internet is a suitable
implementation of such a name to address translation system.
Remote Procedure Call Libraries
In order to provide a standard library interface so that distributed
network utilities can easily communicate with each other in a
standard way, a standard Remote Procedure Call (RPC) library must be
deployed. The computer industry has lead the research community in
developing RPC implementations, and current implementations tend to
be compatible within the same type of operating system, but not
across operating systems. Nonetheless, a portable RPC implementation
that can be standardized can provide a substantial boost in present
capability to write operating system independent network utilities.
If a new RPC mechanism is to be designed from scratch, then it must
have enough capabilities to lure implementors away from current
standards. Otherwise, modification of an existing standard that is
close to the mark in capabilities seems to be in order, with the
cooperation of vendors in the field to assure implementations will
exist for all major operating systems in use on the network.
Remote Job Entry (RJE)
The capabilities of standard network RJE implementations are
inadequate, and are implemented prolifically among major operating
systems. While the notion of RJE evokes memories of dated
technologies such as punch cards, the concept is still valid, and is
favored as a means of interaction with supercomputers by science
users. All major supercomputer manufacturers support RJE access in
their operating systems, but many do not generalize well into the
Internet domain. That is, a RJE standard that is designed for 2400
baud modem access from a card reader may not be easily modifiable for
use on the Internet. Nonetheless, the capability for a network user
to submit a job from a host and have its output delivered on a
printer attached to a different host would be welcomed by most
science users. Further, having this capability interoperate with
existing RJE packages would add a large amount of flexibility to the
whole system.
Multiple Virtual Connections
The capability to have multiple network connections open from a
user's workstation to remote network hosts is an invaluable tool that
greatly increases user productivity. The network design should not
place limits (procedural or otherwise) on this capability.
Network Operation and Management Tools
The present state of internet technology requires the use of
personnel who are, in the vernacular of the trade, called network
"wizards," for the proper operation and management of networks.
These people are a scarce resource to begin with, and squandering
them on day to day operational issues detracts from progress in the
more developmental areas of networking. The cause of this problem is
that a good part of the knowledge for operating and managing a
network has never been written down in any sort of concise fashion,
and the reason for that is because networks of this type in the past
were primarily used as a research tool, not as an operational
resource. While the usage of these networks has changed, the
technology has not adjusted to the new reality that a wizard may not
be nearby when a problem arises. To insure that the network can
flexibly expand in the future, new tools must be developed that allow
non-wizards to monitor network performance, determine trouble spots,
and implement repairs or 'work-arounds'.
Future Goals
The networks of the future must be able to support transparent access
to distributed resources of a variety of different kinds. These
resources will include supercomputer facilities, remote observing
facilities, distributed archives and databases, and other network
services. Access to these resources is to be made widely available
to scientists, other researchers, and support personnel located at
remote sites over a variety of internetted connections. Different
modes of access must be supported that are consonant with the sorts
of resources that are being accessed, the data bandwidths required
and the type of interaction demanded by the application.
Network protocol enhancements will be required to support this
expansion in functionality; mere increases in bandwidth are not
sufficient. The number of end nodes to be connected is in the
hundreds of thousands, driven by increasing use of microprocessors
and workstations throughout the community. Fundamentally different
sorts of services from those now offered are anticipated, and dynamic
bandwidth selection and allocation will be required to support the
different access modes. Large-scale internet connections among
several agency size internets will require new approaches to routing
and naming paradigms. All of this must be planned so as to
facilitate transition to the ISO/OSI standards as these mature and
robust implementations are placed in service and tuned for
performance.
Several specific areas are identified as being of critical importance
in support of future network requirements, listed in no particular
order:
Standards and Interface Abstractions
As more and different services are made available on these
various networks it will become increasingly important to
identify interface standards and suitable application
abstractions to support remote resource access. These
abstractions may be applicable at several levels in the
protocol hierarchy and can serve to enhance both applications
functionality and portability. Examples are transport or
connection layer abstractions that support applications
independence from lower level network realizations or interface
abstractions that provide a data description language that can
handle a full range of abstract data type definitions.
Applications or connection level abstractions can provide means
of bridging across different protocol suites as well as helping
with protocol transition.
OSI Transition and Enhancements
Further evolution of the OSI network protocols and realization
of large-scale networks so that some of the real protocol and
tuning issues can be dealt with must be anticipated. It is
only when such networks have been created that these issues can
be approached and resolved. Type-of-service and Expressway
routing and related routing issues must be resolved before a
real transition can be contemplated. Using the interface
abstraction approach just described will allow definition now
of applications that can transition as the lower layer networks
are implemented. Applications gateways and relay functions
will be a part of this transition strategy, along with dual
mode gateways and protocol translation layers.
Processor Count Expansion
Increases in the numbers of nodes and host sites and the
expected growth in use of micro-computers, super-micro
workstations, and other modest cost but high power computing
solutions will drive the development of different network and
interconnect strategies as well as the infrastructure for
managing this increased name space. Hierarchical name
management (as in domain based naming) and suitable transport
layer realizations will be required to build networks that are
robust and functional in the face of the anticipated
expansions.
Dynamic Binding of Names to Addresses
Increased processor counts and increased usage of portable
units, mobile units and lap-top micros will make dynamic
management of the name/address space a must. Units must have
fixed designations that can be re-bound to physical addresses
as required or expedient.
4. USER SERVICES
The user services of the network are a key aspect of making the
network directly useful to the scientist. Without the right user
services, network users separate into artificial subclasses based on
their degree of sophistication in acquiring skill in the use of the
network. Flexible information dissemination equalizes the
effectiveness of the network for different kinds of users.
Near Term Requirements
In the near term, the focus is on providing the services that allow
users to take advantage of the functions that the interconnected
network provides.
Directory services
Much of the information necessary in the use of the network is for
directory purposes. The user needs to access resources available on
the network, and needs to obtain a name or address.
White Pages
The network needs to provide mechanisms for looking up names and
addresses of people and hosts on the network. Flexible searches
should be possible on multiple aspects of the directory listing.
Some of these services are normally transparent to the user/host name
to address translation for example.
Yellow Pages
Other kinds of information lookup are based on cataloging and
classification of information about resources on the networks.
Information Sharing Services
Bulletin Boards
The service of the electronic bulletin board is the one-to-many
analog of the one-to-one service of electronic mail. A
bulletin board provides a forum for discussion and interchange
of information. Accessibility is network-wide depending on the
definition of the particular bulletin board. Currently the
SMTP and UUCP protocols are used in the transport of postings
for many bulletin boards, but any similar electronic mail
transport can be substituted without affecting the underlying
concept. An effectively open-ended recipient list is specified
as the recipient of a message, which then constitutes a
bulletin board posting. A convention exists as to what
transport protocols are utilized for a particular set of
bulletin boards. The user agent used to access the Bulletin
Board may vary from host to host. Some number of host
resources on the network provide the service of progressively
expanding the symbolic mail address of the Bulletin Board into
its constituent parts, as well as relaying postings as a
service to the network. Associated with this service is the
maintenance of the lists used in distributing the postings.
This maintenance includes responding to requests from Bulletin
Board readers and host Bulletin Board managers, as well as
drawing the appropriate conclusions from recurring
automatically generated or error messages in response to
distribution attempts.
Community Archiving
Much information can be shared over the network. At some point
each particular information item reaches the stage where it is
no longer appropriately kept online and accessible. When
moving a file of information to offline storage, a network can
provide its hosts a considerable economy if information of
interest to several of them need only be stored offline once.
Procedures then exist for querying and retrieving from the set
of offline stored files.
Shared/distributed file system
It should be possible for a user on the network to look at a
broadly defined collection of information on the network as one
useful whole. To this end, standards for accessing files
remotely are necessary. These standards should include means
for random access to remote files, similar to the generally
employed on a single computer system.
Distributed Databases and Archives
As more scientific disciplines computerize their data archives
and catalogs, mechanisms will have to be provided to support
distributed access to these resources. Fundamentally new kins
of collaborative research will become possible when such
resources and access mechanisms are widely available.
Resource Sharing Services
In sharing the resources or services available on the network,
certain ancillary services are needed depending on the
resource.
Access Control
Identification and authorization is needed for individuals, hosts or
subnetworks permitted to make use of a resource available via the
network. There should be consistency of procedure for obtaining and
utilizing permission for use of shared resources. The identification
scheme used for access to the network should be available for use by
resources as well. In some cases, this will serve as sufficient
access control, and in other cases it will be a useful adjunct to
resource-specific controls. The information on the current network
location of the user should be available along with information on
user identification to permit added flexibility for resources. For
example, it should be possible to verify that an access attempt is
coming from within a state. A state agency might then grant public
access to its services only for users within the state. Attributes
of individuals should be codifiable within the access control
database, for example membership in a given professional society.
Privacy
Users of a resource have a right to expect that they have control
over the release of the information they generate. Resources should
allow classifying information according to degree of access, i.e.
none, access to read, access according to criteria specified in the
data itself, ability to change or add information. The full range of
identification information described under access control should be
available to the user when specifying access. Access could be
granted to all fellow members of a professional society, for example.
Accounting
To permit auditing of usage, accounting information should be
provided for those resources for which it is deemed necessary. This
would include identity of the user of the resource and the
corresponding volume of resource components.
Legalities of Interagency Research Internet
To make the multiply-sponsored internetwork feasible, the federal
budget will have to recognize that some usage outside a particular
budget category may occur. This will permit the cross-utilization of
agency funded resources. For example, NSFnet researchers would be
able to access supercomputers over NASnet. In return for this, the
total cost to the government will be significantly reduced because of
the benefits of sharing network and other resources, rather than
duplicating them.
Standards
In order for the networking needs of scientific computing to be met,
new standards are going to evolve. It is important that they be
tested under actual use conditions, and that feedback be used to
refine them. Since the standards for scientific communication and
networking are to be experimented with, they are more dynamic than
those in other electronic communication fields. It is critical that
the resources of the network be expended to promulgate experimental
standards and maximize the range of the community utilizing them. To
this end, the sharing of results of the testing is important.
User-oriented Documentation
The functionality of the network should be available widely without
the costly need to refer requests to experts for formulation. A
basic information facility in the network should therefore be
developed. The network should be self-documenting via online help
files, interactive tutorials, and good design. In addition, concise,
well-indexed and complete printed documentation should be available.
Future Goals
The goal for the future should be to provide the advanced user
services that allow full advantage to be taken of the interconnection
of users, computing resources, data bases, and experimental
facilities. One major goal would be the creation of a national
knowledge bank. Such a knowledge bank would capture and organize
computer-based knowledge in various scientific fields that is
currently available only in written/printed form, or in the minds of
experts or experienced workers in the field. This knowledge would be
stored in knowledge banks which will be accessible over the network
to individual researchers and their programs. The result will be a
codification of scientific understanding and technical know-how in a
series of knowledge based systems which would become increasingly
capable over time.
CONCLUSION
In this paper, we have tried to describe the functions required of
the interconnected national network to support scientific research.
These functions range from basic connectivity through to the
provision for powerful distributed user services.
Many of the goals described in this paper are achievable with current
technology. They require coordination of the various networking
activities, agreement to share costs and technologies, and agreement
to use common protocols and standards in the provision of those
functions. Other goals require further research, where the
coordination of the efforts and sharing of results will be key to
making those results available to the scientific user.
For these reasons, we welcome the initiative represented by this
workshop to have the government agencies join forces in providing the
best network facilities possible in support of scientific research.
APPENDIX
Internet Task Force on Scientific Computing
Rick Adrion University of Massachusetts
Ron Bailey NASA Ames Research Center
Rick Bogart Stanford University
Bob Brown RIACS
Dave Farber University of Delaware
Alan Katz USC Information Science Institute
Jim Leighton Lawrence Livermore Laboratories
Keith Lantz Stanford University
Barry Leiner (chair) RIACS
Milo Medin NASA Ames Research Center
Mike Muuss US Army Ballistics Research Laboratory
Harvey Newman California Institute of Technology
David Roode Intellicorp
Ari Ollikainen General Electric
Peter Shames Space Telescope Science Institute
Phil Scherrer Stanford University