SIMPLE H. Schulzrinne Internet-Draft Columbia U. Expires: January 10, 2005 July 12, 2004 Timed Presence Extensions to the Presence Information Data Format (PIDF) to Indicate Presence Information for Past and Future Time Intervals draft-ietf-simple-future-02 Status of this Memo By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. 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 January 10, 2005. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract The Presence Information Data Format (PIDF) defines a basic XML format for presenting presence information for a presentity. The timed presence extension adds elements to PIDF that allow a presentity to declare their status for a time interval fully in the future or the past. Schulzrinne Expires January 10, 2005 [Page 1]
Internet-Draft Timed Presence July 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology and Conventions . . . . . . . . . . . . . . . . . 4 3. Timed-Status Element . . . . . . . . . . . . . . . . . . . . . 5 4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. The XML Schema Definition . . . . . . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 6.1 URN Sub-Namespace Registration for 'urn:ietf:params:xml:ns:pidf:timed-status' . . . . . . . . 8 6.2 Schema Registration for Schema urn:ietf:params:xml:ns:pidf:timed-status' . . . . . . . . 8 7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8.1 Normative References . . . . . . . . . . . . . . . . . . . . 11 8.2 Informative References . . . . . . . . . . . . . . . . . . . 11 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 11 A. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12 B. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . 14 Schulzrinne Expires January 10, 2005 [Page 2]
Internet-Draft Timed Presence July 2004 1. Introduction Presence information, e.g., represented as PIDF [3] and RPID [4], describes the current state of the presentity. RPID also allows a presentity 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 published and 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 or past status cannot be expressed with <status> elements that use optional attributes or elements indicating such past or future time ranges. If they did, PIDF parsers would ignore those optional attributes or elements, and would not be able to distinguish current information from past or future information. This document defines the <timed-status> element that describes the status of a presentity that is either no longer valid or covers some future timeperiod. Schulzrinne Expires January 10, 2005 [Page 3]
Internet-Draft Timed Presence July 2004 2. Terminology and Conventions The key words MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL in this document are to be interpreted as described in BCP 14, RFC 2119 [1]. Schulzrinne Expires January 10, 2005 [Page 4]
Internet-Draft Timed Presence July 2004 3. Timed-Status Element The <timed-status> element MUST NOT appear as a child of a PIDF <status> element or another <timed-status> element. More than one such element MAY appear within a PIDF <tuple> element. Sources of <timed-status> information should avoid overlapping elements, but since overlapping appointments are common in calendars, for example, receivers MUST be able to render such overlapping <timed-status> indications. The <timed-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 this element is expected to be valid. If the 'until' attribute is missing, the information is assumed valid until the tuple is explicitly overridden or expires as defined by the publication mechanism used. The time range MUST NOT encompass the present time, as that would provide an unnecessary and confusing alternate mechanism to describe presence. Thus, the 'from' attribute for tuples without an 'until' attribute MUST refer to the future. A presence agent (PA) MAY convert stored published <timed-status> tuples which are covering the present time when a notification is sent to regular PIDF tuples or it MAY simply discard them during the composition operation. The <timed-status> element may contain any PIDF element, <basic> and <note>, as well as status extensions, such as RPID [4]. However, not all elements in PIDF extensions are sensible in this context. For example, information such as contact information [5] that does not change as a function of time is inappropriate for use with timed status. 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. Implementations SHOULD ascertain whether the time values in the <timed-status> elements are plausible, for example, by checking whether the time stamp in a notification protocol message corresponds to local time and by making sure that they are fully in the past or future, both relative to real time and the time contained in the optional PIDF <timestamp> element. Schulzrinne Expires January 10, 2005 [Page 5]
Internet-Draft Timed Presence July 2004 4. Example An example combining PIDF and timed-status is shown below: <?xml version="1.0" encoding="UTF-8"?> <presence xmlns="urn:ietf:params:xml:ns:pidf" xmlns:ts="urn:ietf:params:xml:ns:pidf:timed-status" entity="pres:someone@example.com"> <tuple id="7c8dqui"> <status> <basic>open</basic> </status> <ts:timed-status from="2003-08-15T10:20:00.000-05:00" until="2003-08-22T19:30:00.000-05:00"> <basic>closed</basic> </ts:timed-status> <contact>sip:someone@example.com</contact> </tuple> <note>I'll be in Tokyo next week</note> </presence> Schulzrinne Expires January 10, 2005 [Page 6]
Internet-Draft Timed Presence July 2004 5. The XML Schema Definition The schema is shown below. <?xml version="1.0" encoding="UTF-8"?> <xs:schema xmlns="urn:ietf:params:xml:ns:pidf:timed-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 timed-status tuple extensions for PIDF. </xs:documentation> </xs:annotation> <xs:element name="timed-status" type="timed-status"/> <xs:complexType name="timed-status"> <xs:sequence> <xs:element name="basic" type="pidf:basic" minOccurs="0"/> <xs:element name="note" type="pidf:note" minOccurs="0"/> <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> Schulzrinne Expires January 10, 2005 [Page 7]
Internet-Draft Timed Presence July 2004 6. IANA Considerations This document calls for IANA to register a new XML namespace URN and schema per [2]. 6.1 URN Sub-Namespace Registration for 'urn:ietf:params:xml:ns:pidf:timed-status' URI: urn:ietf:params:xml:ns:pidf:timed-status Description: This is the XML namespace for XML elements defined by RFCXXXX to describe timed-status presence information extensions for the status element in the PIDF presence document format in the application/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>Timed Presence Extensions to the Presence Information Data Format (PIDF) to Indicate Presence Information for Past and Future Time Intervals</title> </head> <body> <h1>Namespace for timed-status presence extension</h1> <h2>urn:ietf:params:xml:ns:pidf:timed-status</h2> <p>See <a href="URL of published RFC">RFCXXXX</a>.</p> </body> </html> END 6.2 Schema Registration for Schema urn:ietf:params:xml:ns:pidf:timed-status' URI: please assign Registrant Contact: IESG Schulzrinne Expires January 10, 2005 [Page 8]
Internet-Draft Timed Presence July 2004 XML: See Section 5 Schulzrinne Expires January 10, 2005 [Page 9]
Internet-Draft Timed Presence July 2004 7. Security Considerations The security issues are similar to those for RPID [4]. Schulzrinne Expires January 10, 2005 [Page 10]
Internet-Draft Timed Presence July 2004 8. References 8.1 Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [3] Sugano, H. and S. Fujimoto, "Presence Information Data Format (PIDF)", draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003. 8.2 Informative References [4] Schulzrinne, H., Gurbani, V., Kyzivat, P. and J. Rosenberg, "RPID: Rich Presence: Extensions to the Presence Information Data Format (PIDF)", draft-ietf-simple-rpid-03 (work in progress), March 2004. [5] Schulzrinne, H., "CIPID: Contact Information in Presence Information Data Format", draft-ietf-simple-cipid-02 (work in progress), July 2004. Author's Address Henning Schulzrinne Columbia University Department of Computer Science 450 Computer Science Building New York, NY 10027 US Phone: +1 212 939 7042 EMail: hgs+simple@cs.columbia.edu URI: http://www.cs.columbia.edu Schulzrinne Expires January 10, 2005 [Page 11]
Internet-Draft Timed Presence July 2004 Appendix A. Contributors Jonathan Rosenberg dynamicsoft 600 Lanidex Plaza Parsippany, NJ 07054-2711 USA Email: jdrosen@dynamicsoft.com Schulzrinne Expires January 10, 2005 [Page 12]
Internet-Draft Timed Presence July 2004 Appendix B. Acknowledgments This document is based on the discussions within the IETF SIMPLE working group. Mary Barnes, Miguel Garcia, Vijay Gurbani, Hisham Khartabil, Paul Kyzivat, Mikko Lonnfors, Yannis Pavlidis and Jon Peterson provided helpful comments. Schulzrinne Expires January 10, 2005 [Page 13]
Internet-Draft Timed Presence July 2004 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights 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; nor does it represent that it has made any independent effort to identify any such rights. Information on the IETF's procedures with respect to rights in IETF Documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat 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 implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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. Copyright Statement Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Schulzrinne Expires January 10, 2005 [Page 14]
