Internet Info 1994 March/Internet Info CD-ROM (Walnut Creek) (March 1994).iso/inet/internet-drafts/draft-ietf-iiir-vision-01.txt

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IETF IIIR Working Group                             Chris Weider
INTERNET--DRAFT                              Merit Network, Inc.
<draft-ietf-iiir-vision-01.txt>                                 Peter Deutsch
                                             Bunyip, Inc.
                                 October, 1993

    A Vision of an Integrated Internet Information Service

Status of this Memo

In this paper, the authors put forth their vision of an integrated Internet
information service which ties together the information services currently
deployed and allows them to work together.

      This document is an Internet Draft.  Internet Drafts are working
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        Please check the I-D abstract listing contained in each Internet
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      This Internet Draft expires April 25, 1994.

Abstract

This paper lays out a vision of how Internet information services might
be integrated over the next few years, and discusses in some detail what
steps will be needed to achieve this integration.

0: Acknowledgments

Thanks to the whole gang of information service wonks who have
wrangled with us about the future of information services in countless bar
bofs (in no particular order): Cliff Lynch, Cliff Newman, Alan Emtage,
Jim Fullton, Joan Gargano, Mike Schwartz, John Kunze, Janet Vratny,
Mark McCahill, Tim Berners-Lee, John Curran, Jill Foster, and many others.
Extra special thanks to George Brett of CNIDR and Anders Gillner of
RARE, who have given us the opportunity to start tying together the
networking community and the librarian community.

1: Introduction

The current landscape in information tools is much the same as the landscape
in communications networks in the early 1980's.  In the early 80's, there
were a number of proprietary networking protocols that connected large
but autonomous regions of computers, and it was difficult to coalesce these
regions into a unified network. Today, we have a number of large but
autonomous regions of networked information.  We have a vast set of FTPable
files, a budding WAIS network, a budding GOPHER network, a budding World Wide
Web network, etc.  Although there are a number of gateways between various
protocols, and information service providers are starting to use GOPHER
to provide a glue between various services, we are not yet in that golden
age when all human information is at our fingertips. (And we're even farther
from that platinum age when the computer knows what we're looking for and
retrieves it before we even touch the keyboard.)



IIIR Working Group     Vision of Information Services      Weider, Deutsch

In this paper, we'll propose one possible vision of the information services
landscape of the near future, and lay out a plan to get us there from here.

2: Axioms of information services

There are a number of unspoken assumptions that we've used in our discussions.
It might be useful to lay them out explicitly before we start our exploration.

The first is that there is no _unique_ information protocol that will
provide the flexibility, scale, responsiveness, worldview, and mix of services
that every information consumer wants.  A protocol designed to give quick and
meaningful access to a collection of stock prices might look functionally
very different from one which will search digitized music for a particular
musical phrase and deliver it to your workstation. So, rather than design the
information protocol to end all information protocols, we will always need to
integrate new search engines, new clients, and new delivery paradigms into our
grand information service.

The second is that distributed systems are a better solution to large-scale
information systems than centralized systems.  If one million people are
publishing electronic papers to the net, should they all have to log on to
a single machine to modify the central archives? What kind of bandwidth
would be required to that central machine to serve a billion papers a day?
If we replicate the central archives, what sort of maintenance problems would
be encountered? These questions and a host of others make it seem more
profitable at the moment to investigate distributed systems.

The third is that users don't want to be bothered with the details of the
underlying protocols used to provide a given service. Just as most people
don't care whether their e-mail message gets split up into 20 packets
and routed through Tokyo to get to its destination, information service
users don't care whether the GOPHER server used telnet to get to
a WAIS database back-ended by an SQL database.  They just want the
information. In short, they care very much about how they interact with the
client; they just don't want to know what goes on behind.

These axioms force us to look at solutions which are distributed, support
multiple access paradigms, and allow information about resources to be
handed off from one system (say Gopher) to another (say WWW).

3: An architecture to provide interoperability and integration.

The basic architecture outlined in this paper splits up into 4 levels [Fig.
1].

At the lowest level, we have the resources themselves. These are such things
as files, telnet sessions, online library catalogs, etc. Each resource can
have a resource transponder attached [Weider 93a], and should have a
Uniform Resource Name (URN) [Weider 93b] associated with it to uniquely
identify its contents. If a resource transponder is attached, it will help
maintain the information required by the next level up.

At the next level, we have a 'directory service' that takes a URN and
returns Uniform Resource Locators (URLs) [Berners-Lee 92] for that resource.
The URL is a string which contains location information, and can be used by
a client to access the resource pointed to by the URL.  It is expected that
a given resource may be replicated many times across the net, and thus the
client would get a number of URLs for a given resource, and could choose
between them based on some other criteria.


IIIR Working Group    Vision of Information Service         Weider, Deutsch


      ______________________________________________________________
     |             |            |          |               |
     |              |            |         |               |
     |  Gopher      |  WAIS      | WWW      | Archie        | Others ...
     |           |        |    |        |
     |___________|______________|_______|_______________|___________
          |                                |
          |                       _________|____________
          |                      |                      |
          |                      | Resource Discovery   |
          |                      |  System (perhaps     |
          |                      |  based on whois++)   |
          |                      |______________________|
          |                                |
          |                                |
     _____|________________________________|____
    |                                |
    | Uniform resource name to uniform resource |
    | locator mapping system (perhaps based on  |
    | whois++ or X.500)                      |
    |___________________________________________|
                        |
                        |
        ________________|______________________________________
        |                  |                 |                 |
  ______|______     _______|_____      ______|______     ______|______
 |             |   |             |    |             |   |             |
 | Transponder |   | Transponder |    | Transponder |   | Transponder |
 |_____________|   |_____________|    |_____________|   |_____________|
 |             |   |             |    |             |   |             |
 |             |   |             |    |             |   |             |
 |             |   |             |    |             |   |             |
 |  Resource   |   |  Resource   |    |  Resource   |   |  Resource   |
 |             |   |             |    |             |   |             |
 |             |   |             |    |             |   |             |
 |_____________|   |_____________|    |_____________|   |_____________|


    Figure 1: Proposed architecture of an integrated information
            service

_________________________________________________________________________

The third level of the architecture is a resource discovery system. This
would be a large, distributed system which would accept search criteria
and return URNs and associated information for every resource which matched
the criteria. This would provide a set of URLs which the information service
providers (GOPHER servers, etc.) could then select among for incorporation.

The fourth level of the architecture is comprised of the various information
delivery tools.  These tools are responsible for collating pointers to
resources, informing the user about the resources to which they contain
pointers, and retrieving the resources when the user wishes.

Let's take a look in greater detail at each of these levels.


IIIR Working Group    Vision of Information Service         Weider, Deutsch


3.1 Resource layer

The resources at this layer can be any collection of data a publisher
wishes to catalog. It might be an individual text file, a WAIS database,
the starting point for a hypertext web, or anything else. Each resource
is assigned a URN by the publisher, and the URL is derived from the
current location of the resource. The transponder is responsible for
updating levels 2 and 3 with the appropriate information as the resource
is published and moves around.

3.2 URN -> URL mapping

This level takes a URN and returns a number of URLs for the various
instantiations of that resource on the net.  It will also maintain the URN
space. Thus the only functionality required of this level is the ability
to maintain a global namespace and to provide mappings from that namespace
to the URLs. Consequently, any of the distributed 'directory service'
protocols would allow us to provide that service. However, there may be some
benefit to collapsing levels 2 and 3 onto the same software, in which case
we may need to select the underlying protocol more carefully. For example,
X.500 provides exactly the functionality required by level 2, but does not
(yet) have the functionality required to provide the level 3 service.
In addition, the service at level 2 does not necessarily have to be
provided by a monolithic system. It can be provided by any collection of
protocols which can jointly satisfy the requirements and also interoperate,
so that level 2 does appear to level 3 to be universal in scope.

3.3 Resource discovery

This is the level which requires the most work, and where the greatest
traps lurk to entangle the unwary. This level needs to serve as a giant
repository of all information about every publication, except for that which
is required for the URI -> URL mapping. Since this part is the least filled
in at the moment, we will propose a mechanism which may or may not be the
one which is eventually used.

When a new resource is created on the network, it is assigned a URN determined
by the publisher of the resource. Section 4.1 discusses in more detail the
role of the publisher on the net, but at the moment we can consider only 2
of the publisher's functions. The publisher is responsible for assigning a
URN out of the publishers namespace, and is responsible for notifying a
publishing agent [Deutsch 92] that a new resource has been created; that
agent will either be a part of the resource location service or will then
take the responsibility for notifying an external resource location service
that the resource has been created. Alternatively, the agent can use the
resource location service to find parts of the RLS which should be notified
that this resource has been created.

To give a concrete example, let's say that Peter and Chris publish a multi-
media document titled 'Chris and Peter's Bogus Journey' which talks about
our recent trip to the Antarctic, complete with video clips. P & C would then
ask their publishing agent to generate a URN for this document. They then ask
their publishing agent to attach a transponder to the document, and to
look around and see if anyone a) has asked that our agent notify them whenever
anything we write comes out; or b) is running any kind of server of 'trips
to Antarctica'. Janet has posted a request that she be notified, so the agent
tells her that a new resource has been created. The agent also finds 3


IIIR Working Group    Vision of Information Service         Weider, Deutsch


servers which archive video clips of Antarctica, so the agent notifies
all three that a new resource on Antarctica has come out, and gives out the
URN and a URL for the local copy.

3.4 Information delivery tools

One of the primary functions of an information delivery tool is to collect
and collate pointers to resources. A given tool may provide mechanisms to
group those pointers based on other information about the resource, e.g.
a full-text index allows one to group pointers to resources based on their
contents; archie can group pointers based on filenames, etc. The URLs which
are being standardized in the IETF are directly based on the way World Wide
Web built pointers to resources, by creating a uniform way to specify
access information and location for a resource on the net. With just the
URLs, however, it is impossible without much more extensive checking
to tell whether two resources with different URLs have the same intellectual
content or not. Consequently, the URN is designed to solve this problem.

In this architecture, the pointers that a given information delivery tool
would keep to a resource will be a URN and one or more cached URLs. When
a pointer to a resource is first required (i.e. when a new resource is
linked in a Gopher server), level 2 will provide a set of URLs for that
URN, and the creator of the tool can then select which of those will
be used. As it is expected that the URLs will eventually become stale
(the resource moves, the machine goes down, etc.) the URN can be used
to get a set of current URLs for the resource and an appropriate one can
then be selected. Since the cost of using the level 2 service is probably
greater than the cost of simply resolving a URL, both the URN and the URL
are cached to provide speedy access unless something has moved.

3.5 Using the architecture to provide interoperability between services

In the simplest sense, each interaction that we have with an information
delivery service does one of two things: it either causes a pointer to
be resolved (a file to be retrieved, a telnet session to be initiated, etc.)
or causes some set of the pointers available in the information service to
be selected. At this level, the architecture outlined above provides the
core implementation of interoperability. Once we have a means of mapping
between names and pointers, and we have a standard method of specifying
names and pointers, the interoperation problem becomes one of simply handing
names and pointers around between systems. Obviously with such a simplistic
interoperability scheme much of the flavor and functionality of the
various systems are lost in transition. But, given the pointers, a system
can either a) present them to the user with no additional functionality or
b) resolve the pointers, examine the resources, and then run algorithms
designed to tie these resources together into a structure appropriate for
the current service. Let's look at one example (which just happens to be the
easiest to resolve); interoperation between World Wide Web and Gopher.

Displaying a Gopher screen as a WWW document is trivial with these pointers.
Every Gopher screen is simply a list of menu items with pointers behind them
(we'll ignore the other functionality Gopher provides for a moment), so is
an extremely simple form of a hypertext document. Consequently with this
architecture it is easy to show and resolve a Gopher screen in WWW.
For a WWW to Gopher map, the simplest method would be that when one accesses
a WWW document, all the pointers associated with links off to other
documents are brought in with the document. Gopher could then resolve
the links and read the first line of each document to provide a Gopher
style screen which contains everything in the WWW document. When a link


IIIR Working Group    Vision of Information Service         Weider, Deutsch


is selected, all of the WWW links for the new document are brought in and
the process repeats. Obviously we're losing a lot with the WWW -> Gopher
mapping; some might argue that we are losing everything. However, this
does provide a trivial interoperability capacity, and one can argue that
the 'information content' has been preserved across the gateway.

In addition, the whole purpose of gatewaying is to provide access to resources
that lie outside the reach of your current client. Since all resources are
identifiable and accessible through layers 2 and 3, it will be easy to
copy resources from one protocol to another since all we need to do is to
move the pointers and reexpress the relationships between the pointers in the
new paradigm.

3.6 Other techniques for interoperability

One technique for interoperability which has recently received some serious
attention is the technique of creating one client which speaks the protocols
of all the information delivery tools. This approach has been taken in
particular by the UNITE (User's Network Interface To Everything) group in
Europe. This client would sit on the top level of the architecture in Figure
1. This technique has a lot of appeal; however, there are several practical
difficulties with this approach which may hinder its successful
implementation.

The first difficulty is one that is common to clients in general; the clients
must be constantly updated to reflect changes in the underlying protocols and
to accommodate new protocols. If the increase in the number of information
services is very gradual, or if the underlying protocols do not change very
rapidly, this may not be an insuperable difficulty. In addition, old clients
must have some way of notifying their user that they are no longer current;
otherwise they will no longer be able to access parts of the information mesh.

The second problem is one which may prove more difficult. Each of the
currently deployed information services provides information in a
fundamentally different way. In addition, new information services are likely
to use completely new paradigms for the organization and display of the
information they provide. The various clients of these information services
provide vastly different functionality from each other because the underlying
protocols allow different techniques. It may very well prove impossible to
create a single client which allows access to the full functionality of each
of the underlying protocols while presenting a consistent user interface to
the user.

We will continue to follow this work and may include it in future revisions of
this architecture if it bears fruit.

4: Human interactions with the architecture

In this section we will look at how humans might interact with an information
system based on the above architecture.

4.1 Publishing in this architecture

When we speak of publishing in this section, we are referring only to the
limited process of creating a resource on the net, assigning it a URN, and
spreading the information around that we have created a new resource.

We start with the creation of a resource. Simple enough; a creative thought,
a couple of hours typing, and a few cups of coffee and we have a new resource.
We then wish to assign it a URN. We can talk to whichever publishing agent
we would like; whether it is our own personal publishing agent or some big


IIIR Working Group    Vision of Information Service         Weider, Deutsch

organization that provides URN and announcement services to a large number of
authors.  Once we have a URN, we can provide the publishing agent with
a URL for our local copy of the resource and then let it do its thing.
Alternatively, we can attach a transponder to the resource, let it determine
a local URL for the resource, and let it contact the publishing agent and
set up the announcement process. One would expect a publishing agent to
prompt us for some information as to where it should announce our new
resource.

For example, we may just wish a local announcement, so that only people
in our company can get a pointer to the resource. Or we may wish some sort of
global announcement (but it will probably cost us a bit of money!)

Once the announcement has been made, the publishing agent will be contacted
by a number of pieces of the resource location system. For example, someone
running a WAIS server may decide to add the resource to their index. So
they can retrieve the resource, index it, and add the indexes to their tables
along with a URI - URL combination. Then when someone uses that WAIS server,
it can go off and retrieve the resource if necessary. Or, the WAIS server
could create a local copy of the resource; if it wished other people to
find their local copy of the resource, it could provide the URI -> URL
mapper with a URL for the local copy. In any case, publication becomes a
simple matter.

So, where does this leave the traditional publisher? Well, there are a number
of other functions which the traditional publisher provides in addition to
distribution. There are editorial services, layout and design, copyright
negotiations, marketing, etc.  The only part of the traditional role that this
system changes is that of distributing the resource; this architecture may
make it much cheaper for publishers to distribute their wares to a much wider
audience.

Although copying of resources would be possible just as it is in paper format,
it might be easier to detect republication of the resource in this system, and
if most people use the original URN for the resource, there may be a reduced
monetary risk to the publisher.

4.2 A librarian role in this architecture

We've been in a number of discussions with librarians over the past year,
and one question that we're frequently asked is "Does Peter talk this rapidly
all the time?". The answer to that question is "Yes". But another question
we are frequently asked is "If all these electronic resources are going to
be created, supplanting books and journals, what's left for the librarians?".
The answer to that is slightly more complex, but just as straightforward.
Librarians have excelled at obtaining resources, classifying them so that
users can find them, weeding out resources that don't serve their communities,
and helping users navigate the library itself. None of these roles are
supplanted by this architecture. The only differences are that instead of
scanning publisher's announcements for new resources their users might be
interested in, they will have to scan the announcements on the net.
Once they see something interesting, they can retrieve it (perhaps buying
a copy just as they do now), classify it, set up a navigation system for
their classification scheme, show users how to use it, and provide pointers
(or actual copies) of the resource to their users. The classification and
selection processes in particular are services which will be badly needed
on a net with a million new 'publications' a day, and many will be willing
to pay for this highly value added service.


IIIR Working Group    Vision of Information Service         Weider, Deutsch

4.3 Serving the users

This architecture allows users to see the vast collection of networked
resources in ways both familiar and unfamiliar. Bookstores, record shops,
and libraries can all be constructed on top of this architecture, with a
number of different access methods. Specialty shops and research libraries
can be easily built, and then tailored to a thousand different users.
One never need worry that a book has been checked out, that a CD is out of
stock, that a copy of Xenophon in the original Greek isn't available locally.
In fact, a user could even engage a proxy server to translate resources into
forms that her machine can use, for example to get a text version of a
Postscript document although her local machine has no Postscript viewer,
or to obtain a translation of a sociology paper written in Chinese.

In any case, however the system looks in three, five, or fifty years, we
believe that the vision we've laid out above has the flexibility and
functionality to start tying everything together without forcing everyone
to use the same access methods or to look at the net the same way.
It allows new views to evolve, new resources to be created out of old,
and for people to move from today to tomorrow with all the comforts of
home but all the excitement of exploring a new world.

5: References


[Berners-Lee 93] Berners-Lee, Tim, Universal Resource Locators, Internet
Draft, July 1993. Available for anonymous FTP as
 <ftp://nic.merit.edu/documents/internet-drafts/draft-ietf-uri-url-01.txt>.

Deutsch, Peter, Master's Thesis, June 1992. Available for anonymous FTP as
  <ftp://archives.cc.mcgill.ca/pub/peterd/peterd.thesis>.

[Weider 93a] Weider, Chris, Resource Transponders, Internet Draft, October,
1993. Available for anonymous FTP as
 <ftp://nic.merit.edu/documents/internet-drafts/draft-ietf-iiir-transponders-
01.txt>.

[Weider 93b] Weider, Chris and Peter Deutsch, Uniform Resource Names, Internet
Draft, October, 1993. Available for anonymous FTP as
 <ftp://nic.merit.edu/documents/internet-drafts/draft-ietf-uri-resource-names-
01.txt>.