Hi all!
The YATE server is not processing an incoming INVITE without SDP properly.
According to RFC3261, “When a UAC does not include an SDP body in the INVITE request, it is required that the UAS includes an offer in the first reliable non-failure response”,
In this case the 200 OK towards the IMS should have a SDP offer. However, YATE PBX is "rebounding" the 200 OK from the SoftPhone with an ACK and replying to the initial INVITE with a 200 without SDP, which is not correct.
Is there anyway of overcoming this scenario only through YATE configuration? For instance, simply forward the SDP between end points.
I have attached the .pcap trace for better understanding of the issue
http://www.filedropper.com/yatenosdp