What path does the ACK take, assuming there were proxies in between which inserted Record-routes?
A.If the final response is a non-success response, then the UAC simply sends the ACK on the same path as the INVITE. Only in the case where the final response is a success response does the UAC send the ACK on the new route calculated. This is given to the fact that Ack for negative responses are directly sent by transaction layer and does not have access to the computed routes.
