Publication of Partial Presence Information
RFC 5264
Document | Type | RFC - Proposed Standard (September 2008; No errata) | |
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Authors | Mikko Lonnfors , Eva Leppanen , Aki Niemi | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 5264 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Jon Peterson | ||
Send notices to | (None) |
Network Working Group A. Niemi Request for Comments: 5264 M. Lonnfors Category: Standards Track Nokia E. Leppanen Individual September 2008 Publication of Partial Presence Information 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. Abstract The Session Initiation Protocol (SIP) Extension for Event State Publication describes a mechanism with which a presence user agent is able to publish presence information to a presence agent. Using the Presence Information Data Format (PIDF), each presence publication contains full state, regardless of how much of that information has actually changed since the previous update. As a consequence, updating a sizeable presence document with small changes bears a considerable overhead and is therefore inefficient. Especially with low bandwidth and high latency links, this can constitute a considerable burden to the system. This memo defines a solution that aids in reducing the impact of those constraints and increases transport efficiency by introducing a mechanism that allows for publication of partial presence information. Niemi, et al. Standards Track [Page 1] RFC 5264 Partial Publication September 2008 Table of Contents 1. Introduction ....................................................2 2. Definitions and Document Conventions ............................3 3. Overall Operation ...............................................3 3.1. Presence Publication .......................................3 3.2. Partial Presence Publication ...............................4 4. Client and Server Operation .....................................5 4.1. Content-Type for Partial Publications ......................5 4.2. Generation of Partial Publications .........................5 4.3. Processing of Partial Publications .........................7 4.3.1. Processing <pidf-full> ..............................7 4.3.2. Processing <pidf-diff> ..............................7 5. Security Considerations .........................................8 6. Examples ........................................................8 7. Acknowledgements ...............................................12 8. References .....................................................12 8.1. Normative References ......................................12 8.2. Informative References ....................................13 1. Introduction The Session Initiation Protocol (SIP) Extension for Event State Publication [RFC3903] allows Presence User Agents ('PUA') to publish presence information of a user ('presentity'). The Presence Agent (PA) collects publications from one or several presence user agents, and generates the composite event state of the presentity. The baseline format for presence information is defined in the Presence Information Data Format (PIDF) [RFC3863] and is by default used in presence publication. The PIDF uses Extensible Markup Language (XML) [W3C.REC-xml], and groups data into elements called tuples. In addition, [RFC4479], [RFC4480], [RFC4481], [RFC4482], and [RFC5196] define extension elements that provide various additional features to PIDF. Presence publication by default uses the PIDF document format, and each publication contains full state, regardless of how much of the presence information has actually changed since the previous update. As a consequence, updating a sizeable presence document especially with small changes bears a considerable overhead and is therefore inefficient. Publication of information over low bandwidth and high latency links further exacerbates this inefficiency. This memo specifies a mechanism with which the PUA is after an initial full state publication able to publish only those parts of the presence document that have changed since the previous update. This is accomplished using the partial PIDF [RFC5262] document format Niemi, et al. Standards Track [Page 2] RFC 5264 Partial Publication September 2008 to communicate a set of presence document changes to the PA, who then applies the changes in sequence to its version of the presenceShow full document text