Paul, Besides To tag, From tag, and Call ID, what are the other elements that are essential for a SIP peer-to-peerr relationship b/w two UAs to qualify as a dialog?
The SIP peer-to-peerr relationship b/w a subscriber and a notifier is considered as a dialog, while the relationship b/w a UA and Registrar is not. Is it because the elements such as To tag, From tag, and Call ID in the subscription relationship are used by a Notify transaction? /Guang Paul Kyzivat <[EMAIL PROTECTED]> 03/21/2007 04:25 AM To [EMAIL PROTECTED] cc [email protected] Subject Re: [Sip-implementors] doubt about dialog in RFC 3261 This is widely confusing. Once upon a time the dialog concept wasn't very well defined. REGISTER and INVITE use some of the same elements, so it looks a bit like REGISTER establishes a dialog. Since then the fundamentals of dialogs have been clarified, and new uses of dialogs (e.g. SUBSCRIBE) have been defined. While REGISTER uses some of the elements of a dialog, it doesn't use them all, and just doesn't qualify as a dialog establishing request. You should just view REGISTER as following its own set of rules, without regard for the rules defined for dialog establishment. Paul [EMAIL PROTECTED] wrote: > Hi > > I have a doubt about the dialog concept in RFC 3261. > > In Section 4 Overview of Operation, it says that the combination of the To > tag, From tag, and Call-ID completely defines a peer-to-peer SIP > relationship between two user agent (Alice and Bob) and is referred to as > a dialog. > > In section 12, it says that a dialog is identified at each UA with a > dialog ID, which consists of a Call-ID value, a local tag and a remote > tag. > > In section 10.2 Constructing the REGISTER Request, it says that a REGISTER > request does not establish a dialog. > > A REGISTER request contains From tag and a Call-ID. The 200 response to > the REGISTER typically contains To tag. As a result, a registration > transaction when completed has Call-ID, From tag and To tag to define a > peer-to-peer SIP relationship between a SIP endpoint and the Registrar. > Why this peer-to-peer relationship is not considered as a dialog? > > Thanks > > Guang > > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
