The RFC 3261 text you mentioned is specifically for your first example. Similar text does exist for your second example; however it does not mention adding/setting the Retry-After.
Section 12.2.2: "If the remote sequence number was not empty, but the sequence number of the request is lower than the remote sequence number, the request is out of order and MUST be rejected with a 500 (Server Internal Error) response." > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of Sigrid Thijs > Sent: Wednesday, February 08, 2006 3:21 AM > To: [email protected] > Subject: [Sip-implementors] Server Internal Error with > Retry-After header > > > Hi, > > section 14.2 (UAS Behavior) of RFC3261 states the following: > "A UAS that receives a second INVITE before it sends the final > response to a first INVITE with a lower CSeq sequence number on the > same dialog MUST return a 500 (Server Internal Error) > response to the > second INVITE and MUST include a Retry-After header field with a > randomly chosen value of between 0 and 10 seconds." > > I have a question about the "with a lower CSeq sequence > number" part. Is > that about the first INVITE or the second INVITE? > For example: > INVITE (CSEQ 1) <--- > 180 RINGING (CSEQ 1) ---> > INVITE (CSEQ 2) <--- > 500 SERVER INTERNAL ERROR (with Retry-After header) (CSEQ 2) > ---> ACK (CSEQ 2) <--- > > or: > INVITE (CSEQ 3) <--- > 180 RINGING (CSEQ 3) ---> > INVITE (CSEQ 2) <--- > 500 SERVER INTERNAL ERROR (with Retry-After header) (CSEQ 2) > ---> ACK (CSEQ 2) <--- > > Because the second case doesn't make sense to me, because > when the UAC > would retry the INVITE would be rejected again because of the lower > sequence number. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
