Hi all,
I have an issue with SDP from Kamailio side in the following scenario: simple call from A to B. When B answers a call and sends '200 OK' to A, A delays ACK for a while, so '200 OK' re-transmission happens.
After the fourth try to re-send '200 OK' towards A, Kamailio changes SDP (specifically connection information 'c', IP address become address of A instead of proxy IP as it was in the previous attempts). At some point A sends ACK and call is established, but last received '200 OK' has invalid SDP and it prevents successful media establishment.
I wonder if there any re-transmission counter or whatever what can affect this scenario and change SDP?
Roman Romanchenko VoIP devel Sipwise GmbH
Am Montag, 8. Oktober 2018, 11:59:37 CEST schrieb Roman Romanchenko:
I have an issue with SDP from Kamailio side in the following scenario: simple call from A to B. When B answers a call and sends '200 OK' to A, A delays ACK for a while, so '200 OK' re-transmission happens.
After the fourth try to re-send '200 OK' towards A, Kamailio changes SDP (specifically connection information 'c', IP address become address of A instead of proxy IP as it was in the previous attempts). At some point A sends ACK and call is established, but last received '200 OK' has invalid SDP and it prevents successful media establishment.
I wonder if there any re-transmission counter or whatever what can affect this scenario and change SDP?
Hello Roman,
Kamailio should not change your SDP - unless you use the sdpops module or use a similar transformation in the configuration on the SDP in the SIP message.
If the above is not the case, I can only think that this is a strange bug. We would need more information in this case.
Best regards,
Henning
-
Henning Westerholt -
Roman Romanchenko