Multiple tuples in PIDF Why use multiple tuples? Because there are multiple sources of presence information for a presentity Multiple publishers Could signify persons, devices, etc Multiple contact addresses in tuples signify multiple ways to contact the presentity exact AoR (single SIP tuple) model – an alternative Only a single contact address for SIP is exposed through presence Granularity of presence information blankets all user capabilities/devices This is totally clear, but perhaps not so useful

Tuples w/ contact addresses: the different models Registration model Tuples are husks for contact addresses, address you subscribe to is AoR Contact addresses are different from one another Getting at contact addresses through the registration process rather than through presence However, some devices might not be able to publish presence Correspondence with registration may not be exact Single AoR Markup model Use single AoR with markup (caller prefs) to reach individual devices Capabilities in tuples differentiate alternatives Caller prefs vs. finding “the best way to communicate” Requires extensions Both should work at least as sensibly as the single tuple model

Tuples w/o contact addresses When is it used? Multiple choices: URI you use to subscribe to presence is the same you would use to communicate Non-representable communication addr (since PIDF requires URI as addr) CLOSED tuple Geopriv What do all of these have in common, if anything?

Interoperability concerns Fallback to baseline PIDF But what does baseline PIDF mean? Is it possible to create tuples that would not be compatible with the baseline? Receiving tuples with extensions at incompatible devices What if I get two tuples for the same URI – one open, one closed?

Face-to-face presence Note? If not, why not?