For clarity, the BYE only "cancels" the INVITE for that specific early dialog. Thus the caller may not see the 487; however as before, I'm not sure if you are really asking only about a call without proxy/B2BUA involvement.
Additionally if calling an old device, the following snippet is from rfc3261 section 9.1: "However, a UAC canceling a request cannot rely on receiving a 487 (Request Terminated) response for the original request, as an RFC 2543-compliant UAS will not generate such a response." > -----Original Message----- > From: [email protected] [mailto:sip- > [email protected]] On Behalf Of Iñaki Baz > Castillo > Sent: Tuesday, February 22, 2011 8:39 AM > To: [email protected] > Cc: [email protected] > Subject: Re: [Sip-implementors] SIP flow for BYE sent for early dialog > > 2011/2/22 Nauman Sulaiman <[email protected]>: > > Is the 487 or other non 2XX response a MUST here or is it optional? > > A MUST. The INVITE transaction must be ended. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
