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 8, 2004.

Copyright Notice

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

Abstract

The Future Presence extension adds elements to the Presence Information Data Format (PIDF) that allow a presentity to declare their status for a time in the future.

Table of Contents

1.  Introduction
2.  Future-Status Element
3.  Example
4.  Schema
5.  IANA Considerations
5.1  URN Sub-Namespace Registration for 'urn:ietf:params:xml:ns:pidf:future-status'
6.  Security Considerations
§  Normative References
§  Author's Address
A.  Contributors
B.  Acknowledgments
§  Intellectual Property and Copyright Statements

1. Introduction

Presence information, e.g., represented as PIDF[3] and RPID[2], describes the current state of the presentity. RPID allows to indicate how long certain aspects of the status have been valid and how long they are expected to be valid, but the time range has to include the time when the presence information is delivered to the watcher. (This restriction is necessary to avoid backwards-compatibility problems with plain PIDF implementations.)

In some cases, the watcher can better plan communications if it knows about the presentity's future plans. For example, if a watcher knows that the presentity is about to travel, it might place a phone call earlier.

It is also occasionally useful to represent past information since it may be the only known presence information; it may give watchers an indication of the current status. For example, indicating that the presentity was at a meeting that ended an hour ago indicates that the presentity is likely in transit at the current time.

Future status cannot be expressed with <tuples> elements with optional extensions since PIDF parsers would not be able to distinguish current from future or past information.

This document defines the <future-status> element that describes status information that is either no longer valid or covers some future timeperiod.

2. Future-Status Element

The <future-status> element MUST be qualified with the 'from' attribute and MAY be qualified with an 'until' attribute to describe the time when the status assumed this value and the time until which is element is expected to be valid. The time range MUST NOT encompass the present time, as that would provide an unnecessary and confusing alternate mechanism to describe presence.

Note that this document chooses absolute rather than relative times, since relative times would be too hard to keep properly updated when spacing notifications, for example. Implementors are advised to ascertain whether the time values in the <future-status> elements are plausible, for example, by checking whether the time stamp in a notification protocol message corresponds to local time.

3. Example

An example combining PIDF and future-status is shown in Fig. Figure 1.

<?xml version="1.0" encoding="UTF-8"?>
   <presence xmlns="urn:ietf:params:xml:ns:pidf"
        xmlns:ts="urn:ietf:params:xml:ns:pidf:future-status"
        entity="pres:someone@example.com">

     <tuple id="7c8dqui">
       <contact>sip:someone@example.com</contact>
       <status>
         <basic>open</basic>
       </status>
       <future-status from="2003-08-15T10:20:00.000-05:00"
          until="2003-08-22T19:30:00.000-05:00">
          <basic>closed</basic>
       </future-status>
     </tuple>
     <note>I'll be in Tokyo next week</note>
  </presence>

An Example of Future Status

4. Schema

The schema is shown in Fig. Figure 2.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns="urn:ietf:params:xml:ns:pidf:future-status"
    xmlns:pidf="urn:ietf:params:xml:ns:pidf"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    elementFormDefault="qualified"
    attributeFormDefault="unqualified">

  <!-- This import brings in the XML language attribute xml:lang-->
      <xs:import namespace="http://www.w3.org/XML/1998/namespace"
      schemaLocation="http://www.w3.org/2001/xml.xsd"/>

  <xs:annotation>
    <xs:documentation xml:lang="en">
      Describes future-status tuple extensions for PIDF.
    </xs:documentation> 
  </xs:annotation>

  <xs:element name="future-status" type="future-status"/>

  <xs:complexType name="future-status">
     <xs:sequence>
       <xs:element name="basic" type="pidf:basic" minOccurs="0"/>
       <xs:element name="note" type="pidf:note"/>
       <xs:any namespace="##other" processContents="lax" minOccurs="0"
          maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:attribute name="from" type="xs:dateTime"/>
     <xs:attribute name="until" type="xs:dateTime"/>
  </xs:complexType>
</xs:schema>

The Future-Status Schema

5. IANA Considerations

This document calls for IANA to register a new XML namespace URNs per [4].

5.1 URN Sub-Namespace Registration for 'urn:ietf:params:xml:ns:pidf:future-status'

URI:

urn:ietf:params:xml:ns:future-status

Description:

This is the XML namespace for XML elements defined by RFCXXXX to describe future-status presence information extensions for the status element in the PIDF presence document format in the application/cpim-pidf+xml content type.

Registrant Contact:

IETF, SIMPLE working group, simple@ietf.org; Henning Schulzrinne, hgs@cs.columbia.edu

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>Future-Status Information in Presence Information Data Format</title>
   </head>
   <body>
       <h1>Namespace for future-status presence extension</h1>
       <h2>urn:ietf:params:xml:ns:future-status</h2>
       <p>See <a href="URL of published RFC">RFCXXXX</a>.</p>
    </body>
    </html>
   END

6. Security Considerations

The security issues are similar to those for RPID[2].

Normative References

Author's Address

Appendix A. Contributors

Jonathan Rosenberg
dynamicsoft
600 Lanidex Plaza
Parsippany, NJ 07054-2711
USA
Email: jdrosen@dynamicsoft.com

Appendix B. Acknowledgments

This document is based on the discussions within the IETF SIMPLE working group. Vijay Gurbani, Paul Kyzivat, Jon Peterson and Jonathan Rosenberg have provided helpful comments.

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 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.