From 4bfd864f10b68b71482b35c818559068ef8d5797 Mon Sep 17 00:00:00 2001 From: Thomas Voss Date: Wed, 27 Nov 2024 20:54:24 +0100 Subject: doc: Add RFC documents --- doc/rfc/rfc4481.txt | 507 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 507 insertions(+) create mode 100644 doc/rfc/rfc4481.txt (limited to 'doc/rfc/rfc4481.txt') diff --git a/doc/rfc/rfc4481.txt b/doc/rfc/rfc4481.txt new file mode 100644 index 0000000..e8fc0c4 --- /dev/null +++ b/doc/rfc/rfc4481.txt @@ -0,0 +1,507 @@ + + + + + + +Network Working Group H. Schulzrinne +Request for Comments: 4481 Columbia U. +Category: Standards Track July 2006 + + + Timed Presence Extensions to the + Presence Information Data Format (PIDF) to + Indicate Status Information for Past and Future Time Intervals + +Status of This Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (C) The Internet Society (2006). + +Abstract + + The Presence Information Data Format (PIDF) defines a basic XML + format for presenting presence information for a presentity. This + document extends PIDF, adding a timed status extension + ( element) that allows a presentity to declare its + status for a time interval fully in the future or the past. + +Table of Contents + + 1. Introduction ....................................................2 + 2. Terminology and Conventions .....................................2 + 3. Timed-Status Element ............................................3 + 4. Example .........................................................4 + 5. The XML Schema Definition .......................................5 + 6. IANA Considerations .............................................6 + 6.1. URN Sub-Namespace Registration for + 'urn:ietf:params:xml:ns:pidf:timed-status' .................6 + 6.2. Schema Registration for Schema + 'urn:ietf:params:xml:ns:pidf:timed-status' .................7 + 7. Security Considerations .........................................7 + 8. References ......................................................7 + 8.1. Normative References .......................................7 + 8.2. Informative References .....................................7 + Contributor's Address ..............................................8 + Acknowledgements ...................................................8 + + + + +Schulzrinne Standards Track [Page 1] + +RFC 4481 Timed Presence July 2006 + + +1. Introduction + + Traditionally, presence information, e.g., represented as Presence + Information Data Format [3] (PIDF) and augmented by Rich Presence + Information Data format [9] (RPID), describes the current state of + the presentity. However, a 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. + + In this document, we use terms defined in RFC 2778 [7]. In + particular, a "presentity", abbreviating presence entity, provides + presence information to a presence service. It is typically a + uniquely-identified person. + + RPID already allows a presentity to indicate the period when a + particular aspect of its presence is valid. However, the + element in the PIDF does not have this facility, so that it + is not possible to indicate that a presentity will be OPEN or CLOSED + in the future, for example. + + 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 an off-site meeting that ended an hour ago + indicates that the presentity is likely in transit at the current + time. + + It is unfortunately not possible to simply add time range attributes + to the PIDF element, as PIDF parsers without this capability + would ignore these attributes and thus not be able to distinguish + current from future presence status information. + + This document defines the element that describes the + status of a presentity that is either no longer valid or covers some + future time period. + +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 Standards Track [Page 2] + +RFC 4481 Timed Presence July 2006 + + +3. Timed-Status Element + + The element is a child of the element and MUST + NOT appear as a child of a PIDF element or another + element. More than one such element MAY appear within + a PIDF element. + + Sources of information should avoid elements that + overlap in time, but since overlapping appointments are common in + calendars, for example, receivers MUST be able to render such + overlapping indications. + + + The 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, + i.e., the PIDF value, 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. + + During composition, a presence agent (PA) may encounter a stored + element that covers the present time. The PA MAY + either discard that element or MAY convert it to a regular + element if it considers that information more credible. + + The element may contain the and + elements, as well as any other element that is appropriate as a PIDF + extension and that has a limited validity period. Examples + include the PIDF-LO [8] extensions for location objects. + + This extension chose absolute rather than relative times, since + relative times would be too hard to keep properly updated when + spacing notifications, for example. Originators of presence + information MUST generate time values in the elements + that are fully in the past or future relative to local real + (wallclock) time and the time information contained in the optional + PIDF element. + + + + + + + + + +Schulzrinne Standards Track [Page 3] + +RFC 4481 Timed Presence July 2006 + + +4. Example + + An example combining PIDF and timed-status is shown below: + + + + + + open + + + closed + + sip:someone@example.com + + I'll be in Tokyo next week + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Schulzrinne Standards Track [Page 4] + +RFC 4481 Timed Presence July 2006 + + +5. The XML Schema Definition + + The XML [4] schema [5][6] is shown below. + + + + + + + + + Describes timed-status tuple extensions for PIDF. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Schulzrinne Standards Track [Page 5] + +RFC 4481 Timed Presence July 2006 + + +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 + RFC 4481 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 + + + + Timed Presence Extensions to the Presence + Information Data Format (PIDF) to Indicate Status + Information for Past and Future Time Intervals + + +

Namespace for timed-status presence extension

+

urn:ietf:params:xml:ns:pidf:timed-status

+

See + RFC4481.

+ + + END + + + + + + + + + + + +Schulzrinne Standards Track [Page 6] + +RFC 4481 Timed Presence July 2006 + + +6.2. Schema Registration for Schema + 'urn:ietf:params:xml:ns:pidf:timed-status' + + URI: urn:ietf:params:xml:ns:pidf:timed-status + + Registrant Contact: IESG + + XML: See Section 5 + +7. Security Considerations + + The security issues are similar to those for RPID [9]. + +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., Fujimoto, S., Klyne, G., Bateman, A., Carr, W., and + J. Peterson, "Presence Information Data Format (PIDF)", RFC + 3863, August 2004. + + [4] Yergeau, F., Paoli, J., Sperberg-McQueen, C., Bray, T., and E. + Maler, "Extensible Markup Language (XML) 1.0 (Third Edition)", + W3C REC REC-xml-20040204, February 2004. + + [5] Maloney, M., Beech, D., Thompson, H., and N. Mendelsohn, "XML + Schema Part 1: Structures Second Edition", W3C REC REC- + xmlschema-1-20041028, October 2004. + + [6] Malhotra, A. and P. Biron, "XML Schema Part 2: Datatypes Second + Edition", W3C REC REC-xmlschema-2-20041028, October 2004. + +8.2. Informative References + + [7] Day, M., Rosenberg, J., and H. Sugano, "A Model for Presence and + Instant Messaging", RFC 2778, February 2000. + + [8] Peterson, J., "A Presence-based GEOPRIV Location Object Format", + RFC 4119, December 2005. + + + + + + +Schulzrinne Standards Track [Page 7] + +RFC 4481 Timed Presence July 2006 + + + [9] Schulzrinne, H., Gurbani, V., Kyzivat, P., and J. Rosenberg, + "RPID: Rich Presence Extensions to the Presence Information Data + Format (PIDF)", RFC 4480, July 2006. + +Contributor's Address + + Jonathan Rosenberg + dynamicsoft + 600 Lanidex Plaza + Parsippany, NJ 07054-2711 + USA + EMail: jdrosen@dynamicsoft.com + +Acknowledgements + + This document is based on the discussions within the IETF SIMPLE + working group. Mary Barnes, Avri Doria, Miguel Garcia, Vijay + Gurbani, Hisham Khartabil, Paul Kyzivat, Mikko Lonnfors, Yannis + Pavlidis and Jon Peterson provided helpful comments. + +Author's Address + + Henning Schulzrinne + Columbia University + Department of Computer Science + 450 Computer Science Building + New York, NY 10027 + US + + Phone: +1 212 939 7004 + EMail: hgs+simple@cs.columbia.edu + URI: http://www.cs.columbia.edu + + + + + + + + + + + + + + + + + + + +Schulzrinne Standards Track [Page 8] + +RFC 4481 Timed Presence July 2006 + + +Full Copyright Statement + + Copyright (C) The Internet Society (2006). + + 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. + + 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. + +Intellectual Property + + 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 procedures with respect to rights in RFC 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. + +Acknowledgement + + Funding for the RFC Editor function is provided by the IETF + Administrative Support Activity (IASA). + + + + + + + +Schulzrinne Standards Track [Page 9] + -- cgit v1.2.3