Hi, As per RFC 3261, the UAS MUST add a Contact header field to the 2xx response to the INVITE. The Contact header field contains an address where the UAS would like to be contacted for subsequent requests in the dialog (which includes the ACK for a 2xx response in the case of an INVITE).
My questions are: 1) Would the ACK for a non-2xx response be using this contact address? (I assume not. My understanding is that UAC must send ACK for a non-2xx response using the same destination address as the INVITE) 2) How about PRACK or UPDATE request which is sent from UAC to UAS before the dialog is established (i.e.: 200 ok to INVITE is not sent by UAS yet)? (I assume same as the ACK for non-200 response). Your comments are appreciated. Thanks, Yong _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
