BIN, A registration "relationship" can stay long. Within this relationship, the To tag, From tag and Call ID established by the initial RGISTER/response transaction are shared by subsequent REGISTER/response transactions for the refresh of the same registration.
/Guang Bin Chen <[EMAIL PROTECTED]> Sent by: [EMAIL PROTECTED] 03/21/2007 03:17 AM To [EMAIL PROTECTED] cc [email protected] Subject Re: [Sip-implementors] doubt about dialog in RFC 3261 [EMAIL PROTECTED] 写道: > 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? > IMHO, the concept for dialog is for a long period communication. The semantic for 'long' is that, once the dialog established, the dialog attributes are shared by many in-dialog request/response. For example, the subscribe is a dialog request, after the dialog establishment, there are other request(notify etc) can share the from tag, to tag, callid. But if we treat register a dialog, who will share these attributes from the initial subscribe request? _______________________________________________ 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
