Presence Information Data Format (PIDF) Extension for Partial Presence

Abstract

Presence Information Data Format (PIDF) Extension for Partial Presence Status of This MemoThis 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. AbstractThe Presence Information Document Format (PIDF) specifies the baseline XML-based format for describing presence information. One of the characteristics of the PIDF is that the document always needs to carry all presence information available for the presentity. In some environments where low bandwidth and high latency links can exist, it is often beneficial to limit the amount of transported information over the network. This document introduces a new MIME type that enables transporting of either only the changed parts or the full PIDF-based presence information.

Publication of Partial Presence Information

“…This document makes use of the vocabulary defined in the Model for Presence and Instant Messaging [RFC2778], the Event State Publication Extension to SIP [RFC3903], and the PIDF Extension for Partial Presence [RFC5262].…”

“…Note that the partial PIDF format [RFC5262] contains the 'version' attribute that could be used for versioning as well. However, we chose not to introduce an additional versioning mechanism to partial publish, since that would only add ambiguity and a potentially undefined error case if the two versioning mechanisms were to somehow contradict.…”

“…The consequent modifying publications can carry either state deltas or full state. Both initial and modifying partial presence publications are accomplished using the 'application/pidf-diff+xml' content type [RFC5262], with the former using the <pidf-full> root element, and the latter using the <pidf-diff> or <pidf-full> root elements, respectively.…”

“…The entities supporting the partial publication extension described in this document MUST support the 'application/pidf-diff+xml' content type defined in the partial PIDF format [RFC5262], in addition to the baseline 'application/pidf+xml' content type defined in [RFC3863].…”

“…This is accomplished using the partial PIDF [RFC5262] document format to communicate a set of presence document changes to the PA, who then applies the changes in sequence to its version of the presence document.…”