[Search] [txt|pdf|bibtex] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04 05 rfc4826                                     
SIMPLE                                                      J. Rosenberg
Internet-Draft                                               dynamicsoft
Expires: August 15, 2004                               February 15, 2004


  An Extensible Markup Language (XML) Format for Representing Resource
                                 Lists
                  draft-ietf-simple-xcap-list-usage-02

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that other
   groups may also distribute working documents as Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time. It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at http://
   www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on August 15, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2004). All Rights Reserved.

Abstract

   In multimedia communications, presence and instant messaging systems,
   there is a need to represent lists of Uniform Resource Identifiers
   (URIs). These lists, which typically reside on a server, can be
   subscribed to, in order to learn the presence status of a group of
   users. A Session Initiation Protocol (SIP) INVITE message can be sent
   to them, causing the creation of a conference call. This
   specification defines an Extensible Markup Language (XML) document
   format for representing resource lists. Such a document can be
   manipulated by clients using the XML Configuration Access Protocol
   (XCAP), although other techniques are permitted.





Rosenberg               Expires August 15, 2004                 [Page 1]


Internet-Draft             XML Resource Lists              February 2004


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Structure of a Resource List . . . . . . . . . . . . . . . . .  5
   4.  XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   5.  Example Document . . . . . . . . . . . . . . . . . . . . . . .  9
   6.  Usage with XCAP  . . . . . . . . . . . . . . . . . . . . . . . 10
   6.1 Application Unique ID  . . . . . . . . . . . . . . . . . . . . 10
   6.2 MIME Type  . . . . . . . . . . . . . . . . . . . . . . . . . . 10
   6.3 XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 10
   6.4 Additional Constraints . . . . . . . . . . . . . . . . . . . . 10
   6.5 Data Semantics . . . . . . . . . . . . . . . . . . . . . . . . 10
   6.6 Naming Conventions . . . . . . . . . . . . . . . . . . . . . . 10
   6.7 Resource Interdependencies . . . . . . . . . . . . . . . . . . 10
   6.8 Authorization Policies . . . . . . . . . . . . . . . . . . . . 11
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   8.1 XCAP Application Usage ID  . . . . . . . . . . . . . . . . . . 13
   8.2 application/resource-lists+xml MIME Type . . . . . . . . . . . 13
   8.3 URN Sub-Namespace Registration for
       urn:ietf:params:xml:ns:resource-lists  . . . . . . . . . . . . 14
   8.4 Resource List Schema Registration  . . . . . . . . . . . . . . 15
       Normative References . . . . . . . . . . . . . . . . . . . . . 16
       Informative References . . . . . . . . . . . . . . . . . . . . 17
       Author's Address . . . . . . . . . . . . . . . . . . . . . . . 17
       Intellectual Property and Copyright Statements . . . . . . . . 18
























Rosenberg               Expires August 15, 2004                 [Page 2]


Internet-Draft             XML Resource Lists              February 2004


1. Introduction

   In multimedia communications, presence and instant messaging systems,
   operations are frequently performed on lists of Uniform Resource
   Identifiers (URIs). One such example is a presence list [13]. These
   lists are used by Session Initiation Protocol (SIP) for Instant
   Messaging and  Presence (SIMPLE) [9]Resource List Servers (RLS) [11]
   for processing list subscriptions. A presence list can also be used
   by a user agent that chooses to subscribe to each user in its
   presence list, rather than using a list subscription. In such a case,
   the client would read the list from local storage, and generate
   subscriptions to each member.

   It is common for users to share presence lists. As an example, user A
   may have three people in their list that they wish to tell user B
   about. User A would like to send an email to user B with an
   attachment describing these three people. Should user B open the
   attachment, the three people can be added to their own presence list.
   Doing this requires a standardized format for exchanging lists over
   email, instant messaging, and other communications protocols.

   There are other applications of resource lists besides presence
   lists. Another example is a list of recipients for an instant
   message, or a list of users to invite to a conference bridge.

   This specification describes a common format for representing such a
   list, and for describing the set of actions which may be performed
   against the list. Lists can be hierarchical, and can contain
   sub-lists referenced by a URI.

   Resource list documents can be manipulated by clients using several
   means. One such mechanism is the XML Configuration Access Protocol
   (XCAP) [7]. This specification defines the details necessary for
   using XCAP to manage presence authorization documents.

















Rosenberg               Expires August 15, 2004                 [Page 3]


Internet-Draft             XML Resource Lists              February 2004


2. Terminology

   In this document, the key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
   and "OPTIONAL" are to be interpreted as described in RFC 2119 [1] and
   indicate requirement levels for compliant implementations.













































Rosenberg               Expires August 15, 2004                 [Page 4]


Internet-Draft             XML Resource Lists              February 2004


3. Structure of a Resource List

   A resource list is an XML [2] document that MUST be well-formed and
   SHOULD be valid. Resource list documents MUST be based on XML 1.0 and
   MUST be encoded using UTF-8. This specification makes use of XML
   namespaces for identifying resource list documents and document
   fragments. The namespace URI for elements defined by this
   specification is a URN [3], using the namespace identifier 'ietf'
   defined by [5] and extended by RFC 3688 [6]. This URN is:

      urn:ietf:params:xml:ns:resource-lists

   A resource list document begins with the root element tag
   "resource-lists".  It consists of an optional "mandatory-ns" element
   (defined in XCAP [7]), followed by any number of "list" sub-elements,
   each of which is a resource list. Other elements from different
   namespaces MAY be present for the purposes of extensibility; elements
   or attributes from unknown namespaces MUST be ignored. There are
   three attributes associated with the "list" element. The first is
   "name". This attribute is a descriptive name for the list. It MUST be
   unique amongst all other list elements within the same parent
   element. It serves as a useful, but optional handle to identify a
   list.

   Each list element will also have boolean attributes which indicate a
   specific action that may be made against that list. This
   specification defines a single attribute - "subscribeable" - which
   indicates that the list may be subscribed to using the SIP event list
   specification [11]. This application usage does not provide any
   information on which users would be authorized to subscribe to the
   list, however.

   Extensions to this application usage MAY define additional boolean
   elements, each within a different namespace, for the purposes of
   indicating other actions that may be peformed. When an attribute is
   absent, it implies that the operation is not supported.

   The third other attribute, "uri" MAY be present. It provides a URI
   that can be used to access the list, for example, using the SIP event
   notification extension for lists [11]. As a result, the URI MUST be
   either a SIP URI or a pres URI [12].

   Each "list" element is composed of a sequence of zero or more
   elements, each of which may be an "entry" element, a "list" element,
   an "entry-ref" element, or an "external" element. The ability of a
   "list" element to contain other "list" elements means that a resource
   list can be hierarchically structured. An "entry" element describes a
   single URI that is part of the list. An "entry-ref" element allows an



Rosenberg               Expires August 15, 2004                 [Page 5]


Internet-Draft             XML Resource Lists              February 2004


   entry to be included by reference, rather than by value. The content
   of "entry-ref" is a URI that points to an "entry" element in this
   document or another. This URI MUST be an HTTP URI identifying an XCAP
   resource. An "external" element contains a reference to a list stored
   on another server. The content of this element MUST also be an HTTP
   URI identifying an XCAP resource. A "list" element can also contain
   elements from other namespaces, for the purposes of extensibility.

   The "entry" element describes a single resource. The "entry" element
   has two attributes:

      name: This optional attribute is a unique identifier amongst all
      other "entry" elements of the same parent.

      uri: This mandatory attribute is a URI that is used to access the
      resource. It MUST be either a SIP or pres URI.

   The "entry" element contains a sequence of other elements. Only one
   such element is defined at this time, which is "display-name". This
   element provides a UTF-8 encoded string, meant for consumption by the
   user, that describes the resource. Unlike the "name" attribute of the
   entry element, the "display-name" has no uniqueness requirements.
   Other elements from other namespaces MAY be included. This is meant
   to support the inclusion of other information about the entry, such
   as a phone number or postal address.


























Rosenberg               Expires August 15, 2004                 [Page 6]


Internet-Draft             XML Resource Lists              February 2004


4. XML Schema

   The following is the XML schema definition of the resource list:


   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema targetNamespace="urn:ietf:params:xml:ns:resource-lists"
   xmlns:xcap="urn:ietf:params:xml:ns:xcap-must-understand"
   xmlns="urn:ietf:params:xml:ns:resource-lists"
   xmlns:xs="http://www.w3.org/2001/XMLSchema"
   elementFormDefault="qualified" attributeFormDefault="unqualified">
    <xs:import namespace="urn:ietf:params:xml:ns:xcap-must-understand"/>
    <xs:element name="resource-lists">
     <xs:complexType>
      <xs:sequence>
       <xs:element ref="xcap:mandatory-ns" minOccurs="0"/>
       <xs:element name="list" type="listType" minOccurs="0"
        maxOccurs="unbounded"/>
      </xs:sequence>
     </xs:complexType>
    </xs:element>
    <xs:complexType name="listType">
     <xs:sequence maxOccurs="unbounded">
      <xs:choice>
       <xs:element name="list" minOccurs="0" maxOccurs="unbounded">
        <xs:complexType>
         <xs:complexContent>
          <xs:extension base="listType"/>
         </xs:complexContent>
        </xs:complexType>
       </xs:element>
       <xs:element name="external" type="xs:anyURI" minOccurs="0"
        maxOccurs="unbounded"/>
       <xs:element name="entry" type="entryType" minOccurs="0"
        maxOccurs="unbounded"/>
       <xs:element name="entry-ref" type="xs:anyURI" minOccurs="0"
        maxOccurs="unbounded"/>
       <xs:any namespace="##other" processContents="lax" minOccurs="0"
        maxOccurs="unbounded"/>
      </xs:choice>
     </xs:sequence>
     <xs:attribute name="name" type="xs:string" use="optional"/>
     <xs:attribute name="uri" type="xs:anyURI" use="optional"/>
     <xs:attribute name="subscribeable" type="xs:boolean" use="optional"/>
     <xs:anyAttribute namespace="##other"/>
    </xs:complexType>
    <xs:complexType name="entryType">
     <xs:sequence>



Rosenberg               Expires August 15, 2004                 [Page 7]


Internet-Draft             XML Resource Lists              February 2004


      <xs:element name="display-name" type="display-nameType" minOccurs="0"/>
      <xs:any namespace="##other" processContents="lax"
       minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:attribute name="name" type="xs:string" use="optional"/>
     <xs:attribute name="uri" type="xs:anyURI" use="required"/>
    </xs:complexType>
    <xs:simpleType name="display-nameType">
     <xs:restriction base="xs:string"/>
    </xs:simpleType>
   </xs:schema>








































Rosenberg               Expires August 15, 2004                 [Page 8]


Internet-Draft             XML Resource Lists              February 2004


5. Example Document

   The following is an example of a document compliant to the schema:


   ]]>













































Rosenberg               Expires August 15, 2004                 [Page 9]


Internet-Draft             XML Resource Lists              February 2004


6. Usage with XCAP

   Resource list documents can be manipulated with XCAP. This section
   provides the details necessary for such a usage.

6.1 Application Unique ID

   XCAP requires application usages to define a unique application usage
   ID (AUID) in either the IETF tree or a vendor tree. This
   specification defines the "resource-lists" AUID within the IETF tree,
   via the IANA registration in Section 8.

6.2 MIME Type

   The MIME type for this document is "application/resource-lists+xml".

6.3 XML Schema

   The XML Schema for this document is defined as the sole content of
   Section 4.

6.4 Additional Constraints

   None.

6.5 Data Semantics

   Semantics for the document content are provided in Section 3.

6.6 Naming Conventions

   There are no naming conventions that need to be defined for this
   application usage. A subscription to a resource list will be to a
   specific URI. That URI will be one of the "uri" attributes defined in
   a list within one of the documents managed by an XCAP server.

6.7 Resource Interdependencies

   An XCAP server supporting this application usage need only worry
   about a single data interdependency - the "uri" attribute of the list
   element.

   If the "uri" attribute is absent in a document written to an XCAP
   server, but the "subscribeable" flag is true, the XCAP server MUST
   allocate a URI for this list. This allocated URI MUST be globally
   unique, and MUST route to an RLS which will handle list subscriptions
   for the list defined by the document. The server MUST set the uri
   attribute of the document with this URI.



Rosenberg               Expires August 15, 2004                [Page 10]


Internet-Draft             XML Resource Lists              February 2004


   A server MUST NOT delete the "uri" attribute, however, should a
   client change the subscribeable flag to false after the server has
   allocated a URI.

   If the "uri" attribute is present in a document written to an XCAP
   server, but the URI exists in another document managed by the server,
   the document is considered invalid. A server MUST reject such a
   request with a 409, and MAY include an XCAP error report in the body
   indicating this condition. The server MAY suggest, using the "alt-ns"
   element, alternate suggestions for a URI that is not currently
   allocated.

6.8 Authorization Policies

   This application usage does not modify the default XCAP authorization
   policy, which is that only a user can read, write or modify their own
   documents. A server can allow priveleged users to modify documents
   that they don't own, but the establishment and indication of such
   policies is outside the scope of this document. It is anticipated
   that a future application usage will define which users are allowed
   to modify a list resource.






























Rosenberg               Expires August 15, 2004                [Page 11]


Internet-Draft             XML Resource Lists              February 2004


7. Security Considerations

   The configuration information defined by this application usage is
   particularly sensitive. It represents the principle set of people
   with whom a user would like to communicate. As a result, clients
   SHOULD use TLS when contacting servers in order to fetch this
   information. Note that this does not represent a change in
   requirement strength from XCAP.











































Rosenberg               Expires August 15, 2004                [Page 12]


Internet-Draft             XML Resource Lists              February 2004


8. IANA Considerations

   There are several IANA considerations associated with this
   specification.

8.1 XCAP Application Usage ID

   This section registers a new XCAP Application Usage ID (AUID)
   according to the IANA procedures defined in [7].

      Name of the AUID: resource-lists

      Description: A resource list application is any application that
      needs access to a list of resources, identified by a URI, to which
      operations, such as subscriptions, can be applied.


8.2 application/resource-lists+xml MIME Type

      MIME media type name: application

      MIME subtype name: resource-lists+xml

      Mandatory parameters: none

      Optional parameters: Same as charset parameter application/xml as
      specified in RFC 3023 [4].

      Encoding considerations: Same as encoding considerations of
      application/xml as specified in RFC 3023 [4].

      Security considerations: See Section 10 of RFC 3023 [4] and
      Section 7 of this specification.

      Interoperability considerations: none.

      Published specification: This document.

      Applications which use this media type: This document type has
      been used to support subscriptions to lists of users [11] for
      SIP-based presence [9].

      Additional Information:

         Magic Number: None






Rosenberg               Expires August 15, 2004                [Page 13]


Internet-Draft             XML Resource Lists              February 2004


         File Extension: .rl or .xml

         Macintosh file type code: "TEXT"

         Personal and email address for further information: Jonathan
         Rosenberg, jdrosen@jdrosen.net

         Intended usage: COMMON

         Author/Change controller: The IETF.


8.3 URN Sub-Namespace Registration for
    urn:ietf:params:xml:ns:resource-lists

   This section registers a new XML namespace, as per the guidelines in
   RFC 3688 [6].

      URI: The URI for this namespace is
      urn:ietf:params:xml:ns:resource-lists.

      Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org),
      Jonathan Rosenberg (jdrosen@jdrosen.net).

      XML:


                BEGIN
                <?xml version="1.0"?>
                <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
                          "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
                <html xmlns="http://www.w3.org/1999/xhtml">
                <head>
                  <meta http-equiv="content-type"
                     content="text/html;charset=iso-8859-1"/>
                  <title>Resource Lists Namespace</title>
                </head>
                <body>
                  <h1>Namespace for Resource Lists</h1>
                  <h2>application/resource-lists+xml</h2>
                  <p>See <a href="[[[URL of published RFC]]]">RFCXXXX</a>.</p>
                </body>
                </html>
                END







Rosenberg               Expires August 15, 2004                [Page 14]


Internet-Draft             XML Resource Lists              February 2004


8.4 Resource List Schema Registration

   This section registers an XML schema per the procedures in [6].

      URI: please assign.

      Registrant Contact: IETF, SIMPLE working group, (simple@ietf.org),
      Jonathan Rosenberg (jdrosen@jdrosen.net).

      The XML for this schema can be found as the sole content of
      Section 4.








































Rosenberg               Expires August 15, 2004                [Page 15]


Internet-Draft             XML Resource Lists              February 2004


Normative References

   [1]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
        Levels", BCP 14, RFC 2119, March 1997.

   [2]  Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler,
        "Extensible Markup Language (XML) 1.0 (Second Edition)", W3C
        FirstEdition REC-xml-20001006, October 2000.

   [3]  Moats, R., "URN Syntax", RFC 2141, May 1997.

   [4]  Murata, M., St. Laurent, S. and D. Kohn, "XML Media Types", RFC
        3023, January 2001.

   [5]  Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
        August 1999.

   [6]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January
        2004.

   [7]  Rosenberg, J., "The Extensible Markup Language (XML)
        Configuration Access Protocol (XCAP)", draft-ietf-simple-xcap-01
        (work in progress), October 2003.




























Rosenberg               Expires August 15, 2004                [Page 16]


Internet-Draft             XML Resource Lists              February 2004


Informative References

   [8]   Day, M., Rosenberg, J. and H. Sugano, "A Model for Presence and
         Instant Messaging", RFC 2778, February 2000.

   [9]   Rosenberg, J., "A Presence Event Package for the Session
         Initiation Protocol (SIP)", draft-ietf-simple-presence-10 (work
         in progress), January 2003.

   [10]  Roach, A., "Session Initiation Protocol (SIP)-Specific Event
         Notification", RFC 3265, June 2002.

   [11]  Roach, A., Rosenberg, J. and B. Campbell, "A Session Initiation
         Protocol (SIP) Event Notification Extension for  Resource
         Lists", draft-ietf-simple-event-list-04 (work in progress),
         June 2003.

   [12]  Peterson, J., "Common Profile for Presence (CPP)",
         draft-ietf-impp-pres-04 (work in progress), October 2003.

   [13]  Rosenberg, J. and M. Isomaki, "Requirements for Manipulation of
         Data Elements in Session Initiation  Protocol (SIP) for Instant
         Messaging and Presence Leveraging Extensions (SIMPLE) Systems",
         draft-ietf-simple-data-req-03 (work in progress), June 2003.


Author's Address

   Jonathan Rosenberg
   dynamicsoft
   600 Lanidex Plaza
   Parsippany, NJ  07054
   US

   Phone: +1 973 952-5000
   EMail: jdrosen@dynamicsoft.com
   URI:   http://www.jdrosen.net














Rosenberg               Expires August 15, 2004                [Page 17]


Internet-Draft             XML Resource Lists              February 2004


Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; neither does it represent that it
   has made any effort to identify any such rights. Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in BCP-11. Copies of
   claims of rights made available for publication and any assurances of
   licenses to be made available, or the result of an attempt made to
   obtain a general license or permission for the use of such
   proprietary rights by implementors or users of this specification can
   be obtained from the IETF Secretariat.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights which may cover technology that may be required to practice
   this standard. Please address the information to the IETF Executive
   Director.


Full Copyright Statement

   Copyright (C) The Internet Society (2004). All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assignees.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION



Rosenberg               Expires August 15, 2004                [Page 18]


Internet-Draft             XML Resource Lists              February 2004


   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.











































Rosenberg               Expires August 15, 2004                [Page 19]