Publication of Partial Presence Information
Auli Niemi, M. Lonnfors, Esa Leppänen · 2008
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. 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