8 Oct
2018
8 Oct
'18
5:59 a.m.
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
15 Oct
15 Oct
3:21 p.m.
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 - https://skalatan.de/blog/
Kamailio security assessment - https://skalatan.de/de/assessment
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participants (2)
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Henning Westerholt -
Roman Romanchenko