> -----Original Message----- > From: Adam Roach [mailto:[EMAIL PROTECTED] > Sent: Wednesday, September 26, 2007 2:36 PM > > "INFO" means... well... it doesn't mean *ANY*thing. It means "here's > some stuff, now you guess what you're supposed to do with it." So, it is > conceivable that INFO could carry content that describes a session, or > contains renderable content (DTMF!), or describes the state of a > resource. Because these content types necessarily make sense in the > context of other methods that may be supported, it is impossible to tell > whether they make sense in an INFO. So, if a UA advertises support for > INFO and for "image/jpeg", it's not as clear whether they support them > in conjunction with each other. Maybe you think you can use this to > update your user icon in my buddy list... maybe it's just there because > I can receive them in MESSAGE requests. It's impossible to tell, because > INFO *has* *no* *inherent* *meaning*. In theory, every MIME type > imaginable "makes sense" in an INFO.
Well, the way I read the INFO rfc would make application/sdp inappropriate for INFO. But there's no question it's a catch-all method. But that's the *point* of INFO I thought - it was going to leave the semantics up to future headers or bodies to define. But it did not have the full notion of event packages. > However, the problems with INFO in general -- that is, when looking at > the problem without DTMF blinders on -- are intractable without some > kind of explicit indication of intended meaning. And, at the risk of > sounding like a broken record, intended meaning should be conveyed by > method type; that's what the method type is for. But it is and it isn't. I send you an Invite because I want to create a session with you, but the type of session is in the body. I Subscribe for event/state change information from you, but the details about what-for are in the event package. Subscribe as a method doesn't tell you squat really. So I want to send you Info relating to a session but the details about what info are in the content-type. Now I agree that content-type is really not the appropriate header for such generically, specifically because it describes the body content, which may be ambiguous with usage of the body. "application/dtmf" I do NOT think is ambiguous, but "image/jpeg" sure would be. But I think that is something that could be standardized away if we needed to. One way could be to define an Event package type model for it. One could argue Info is essentially a Notify, except in a subscription implicitly created by, and tied to the dialog from, an Invite. -hadriel _______________________________________________ Sip mailing list https://www1.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
