Markus Isomäki Eva Leppänen XCAP Usage for Publishing Presence Information draft-isomaki-simple-xcap-publish-usage-00 Markus Isomäki Eva Leppänen

Motivation SIP PUBLISH allows a particular PUA to publish its view of the presentity, separate from other views published by other PUAs It is not possible for other PUAs to fetch this information The data published using SIP PUBLISH is always associated with an expiration time Infinite expiration time has issues with state cleanup etc. There is a need to be able to publish PUA/device independent data about the presentity Parts of this data change very infrequently It must be possible to fetch and update this data from any device Examples of this kind of data Presentity’s homepage Presentity’s e-mail address Note ”I’m on holiday without any connectivity for the next 3 weeks”

Why XCAP? Using XCAP seems like an obvious solution XCAP allows manipulation of XML-based data on a server Multi-client support Partial updates Presence data is XML-based SIMPLE Presence applications already use XCAP to manipulate lists and presence authorization policies This was also consensus on SIMPLE WG mailing list publishing discussion and during SIMPLE WG session at IETF #57

What the Draft Specifies Actually, there is very little to specify AUID ”presence-publish” PIDF XML schema and its extensions (RPID, CIPID, Prescaps, …) No computed data or additional constraints Basic XCAP/HTTP PUT, GET, DELETE operations take care of the rest

Co-Existence with SIP PUAs +---------------+ +------------+ | Event State | | Presence |<-- SIP SUBSCRIBE | Compositor +---------+ Agent |--> SIP NOTIFY | | | (PA) | +-------+-------+ +------------+ | | +---------------+ +--------------^-------------| XCAP server | | | +-------+-------+ | | ^ | SIP Publish | | XCAP Publish | | | +--+--+ +--+--+ +--------+--------------+ | PUA | | PUA | | XCAP presence-publish | | | | | | clients | +-----+ +-----+ +-----------------------+

Open Issues How to publish content which is ”external” to PIDF? Images, logos etc. Proposal: Upload external content via HTTP Insert the HTTP URI to PIDF document Allow the Presence Agent to include this content into NOTIFY as a separate MIME part, replacing the HTTP URI with the corresponding CID URI PA can as well leave the HTTP URI unmodified, if the URI is accessible by the watchers

Next Steps Adopt this as WG draft Submit a new version shortly Improve the motivation section Make recommendations when to use SIP PUBLISH and when XCAP Improve the language in general