Uniform Resource Agents (URAs)
RFC 2016

Document Type RFC - Experimental (October 1996; No errata)
Was draft-daigle-ura (individual)
Last updated 2013-03-02
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Network Working Group                                          L. Daigle
Request for Comments: 2016                                    P. Deutsch
Category: Experimental                                         B. Heelan
                                                              C. Alpaugh
                                                           M. Maclachlan
                                        Bunyip Information Systems, Inc.
                                                            October 1996

                     Uniform Resource Agents (URAs)

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  This memo does not specify an Internet standard of any
   kind.  Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Abstract

   This paper presents an experimental architecture for an agent system
   that provides sophisticated Internet information access and
   management.  Not a generalized architecture for active objects that
   roam the Internet, these agents are modeled as extensions of existing
   pieces of the Internet information infrastructure.  This experimental
   agent technology focuses on the necessary information structures to
   encapsulate Internet activities into objects that can be activated,
   transformed, and combined into larger structured activities.

Acknowledgements

   Several people have shared thoughts and viewpoints that have helped
   shape the thinking behind this work over the past few years.  We'd
   like to thank, in particular, Chris Weider, Patrik Faltstrom, Michael
   Mealling, Alan Emtage, and the participants in the IETF URI Working
   Group for many thought-provoking discussions.

   Sima Newell provided insightful comments on the document -- thanks to
   her it is much more readable!

Introduction

   This document outlines an experimental agent system architecture that
   was designed for the purpose of addressing high-level Internet
   activities through encapsulation of protocol-specific actions.
   Originally presented to the Uniform Resource Identifier (URI) working
   group at the IETF, this technology was seen as taking a step beyond
   resource location and resource naming.  By providing a structured
   mechanism for abstracting characteristics of desired information and

Daigle, et. al.               Experimental                      [Page 1]
RFC 2016                Uniform Resource Agents             October 1996

   distancing the necessary access incantations from the client, the
   notion of a Uniform Resource Agent (URA) was created.

   The evolution of Internet information systems has been characterized
   by building upon successive layers of encapsulated technologies.
   Machine address numbers were devised, and then encapsulated in
   advertised machine names, which has allowed the evolution of the
   Domain Name System (DNS) [RFC1034, RFC1035].  Protocols were
   developed for accessing Internet resources of various descriptions,
   and then uniform mechanisms for specifying resource locations,
   standardized across protocol types, were developed (URLs) [RFC1738].
   Each layer of Internet information primitives has served as the
   building blocks for the next level of abstraction and sophistication
   of information access, location, discovery and management.

   The work described in this paper is an experimental system designed
   to take another step in encapsulation.  While TCP/IP protocols for
   routing, addressing, etc, have permitted the connection and
   accessibility of a plethora of information services on the Internet,
   these must yet be considered a diverse collection of heterogeneous
   resources.  The World Wide Web effort is the most successful to date
   in attempting to knit these resources into a cohesive whole.
   However, the activity best-supported by this structure is (human)
   browsing of these resources as documents.  The URA initiative
   explores the possibility of specifying an activity with the same kind
   of precision accorded to resource naming and identification.  By
   focusing on activities, and not actions, URAs encapsulate resource
   access mechanisms based on commonality of information content, not
   protocol similarity.

   An invoker -- human or otherwise -- may delegate an entire set of
   tasks to a fully-instantiated URA.  The nature of the tasks is
   completely specified by the agent, because it encapsulates knowledge
   about relevant Internet resources and the information required in
   order to access them.  In this way, URAs insulate invokers from the
   details of Internet protocols while allowing them to carry out high-
   level Internet activities (such as searching a set of web pages and
   news groups relevant to a given topic).  Also, by formally specifying
   a high-level Internet activity in an agent, the same activity can be
   repeated at a later date by the same invoker, someone else or even
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