> > The following is a non service example. > > > > B2BUA aware of Session-Expires activated upon early dialog by UPDATE. > > B2BUA does not receive refresh in time; it sends BYE towards called > party > > for 1 of multiple early dialogs for branch. > > Yes, in theory it can be implemented since it's written :) > That's why I insist on "real" implementations :)
It is real. Hitting it within a deployment is a separate issue. :) > > > since RFC3261 is not strict about the need of Contact and RR headers > > > in 1XX responses, we cannot expect sending an in-dialog request (BYE) > > > during an early-dialog to work. > > > > If I recall correctly (sorry no time dig up references), RFC 3261 > > is strict about adding Contact although it may be hidden within the > > text. The To tag is required to form a dialog; Contact is required > > to be included within dialog forming responses. > > Yes, but RFC 3261 states that Contact is required in reliable > responses, and according to RFC 3261 1XX are not reliable. > I remember a long thread about it and it was clear that... it > wasn't clear :) The following was one of the threads: https://lists.cs.columbia.edu/pipermail/sip-implementors/2008-August/020062.html Read sections 12.1 and 12.1.1: "Within this specification, only 2xx and 101-199 responses with a To tag, where the request was INVITE, will establish a dialog." "When a UAS responds to a request with a response that establishes a dialog (such as a 2xx to INVITE), the UAS MUST copy all Record-Route header field values from the request into the response (including the URIs, URI parameters, and any Record-Route header field parameters, whether they are known or unknown to the UAS) and MUST maintain the order of those values. The UAS MUST add a Contact header field to the response." > In fact I've seen lots of implementations not adding Contact and RR in 1XX > responses. Yes; there are many non compliant devices. _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
