SIP SIMPLE PIDF: Convention for “Do not disturb” DND presence extension

Question

In relation to RFC4480: RPID: Rich Presence Extensions to the Presence Information Data Format (PIDF) there is no activity for DND: Do not disturb.

On the other hand there are many SIP telephone systems on the market that does support DND. Is there a convention to support DND in a "standard" way for presence?

Answer 1

DND is a slightly different animal than merely a status, which SIMPLE can accomplish. More specifically, it's a state of the UA that affects behavior. In the real world, this is usually implemented by handsets by by returning a 480 Temporarily Unavailable, or in the case of a system acting as a B2BUA, this usually works in concert with SIMPLE to convey user status and the local PBX returns a 480 on their behalf in the first leg of the INVITE. For example, this is how the 3Com VCX does things, and Adtran PBX's.

In a nutshell, SIMPLE could only say you are unavailable, not actually effect it. To the best of my knowledge this is no standard, and if there is, I have not seen it used. Caveat: my experience is limited to the 3Com, Aastra, and Adtran systems.