[Spce-user] Command “RTP” converts SAVPF to AVP — F is missing in the destination

[Richard Fuchs]

No such option currently, no. The idea is to have knowledge of the 
protocol supported by the destination and then force exactly that 
protocol, independent of what was originally offered.

It wouldn't be too difficult to add an option to manipulate just one 
aspect of the protocol, just someone needs to do it. 😃 Or you can do it 
conditionally from the signalling proxy based on what was present in the 
SDP.

BTW we have a separate rtpengine-specific mailing list: 
https://rtpengine.com/mailing-list

Cheers


On 08/04/2023 14.56, Дилян Палаузов wrote:
> Hello Richard,
>
> thanks for your answer.  Is there an option to keep the AVP(F) unmodified and just to remove the encryption?
>
> The use case is that I want to have these ENUM tests at http://enum-test.at/index.html running and they do not support encryption.  So just when
> calling there I want to change SAVP to AVP and SAVPF to AVPF.
>
> -----Original Message-----
> From: Richard Fuchs via Spce-user <spce-user at lists.sipwise.com>
> Reply-To: Richard Fuchs <rfuchs at sipwise.com>
> To: spce-user at lists.sipwise.com
> Subject: Re: [Spce-user]  Command “RTP” converts SAVPF to AVP — F is missing in the destination
> Date: 04/08/2023 08:47:50 PM
>
> That's not really how it works though. As soon as one of these protocol
> options is given, the protocol is selected from the options given. The
> original protocol is not taken into account. So with only "RTP" given,
> that comes out as RTP/AVP, because AVP is the default is AVPF is not.
>
> Cheers
>
>
> On 08/04/2023 11.30, Дилян Палаузов via Spce-user wrote:
>> Hello,
>>
>> kamailio/rtpengine receives SDP containing:
>>
>> m=audio 28782 UDP/TLS/RTP/SAVPF 111 63 9 0 8 13 110 126
>>
>> In order to remove the security, I call in Kamailio
>>
>> KSR.rtpengine.rtpengine_manage("replace-session-connection replace-origin SDES-pad SIP-source-address RTP")
>>
>> The outgoing SDP contains:
>>
>> m=audio 39954 RTP/AVP 111 63 9 0 8 13 110 126
>>
>>
>> Considering that the code says nothing about AVP my expectation is that SAVPF is converted to AVPF and the system sends RTP/AVPF.  That is, I expect
>> as output
>>
>> m=audio 39954 RTP/AVPF 111 63 9 0 8 13 110 126
>>
>> My expectation is based also on my reading of https://kamailio.org/docs/modules/devel/modules/rtpengine.html :
>>
>>> RTP, SRTP, DTLS, AVP, AVPF - These flags control the RTP transport protocol that should be used towards the recipient of the SDP. If none of them
>> are specified, the protocol given in the SDP is left untouched. Otherwise, the “SRTP” flag indicates that SRTP should be used, while “RTP” indicates
>> that SRTP should not be used. “AVPF” indicates that the advanced RTCP profile with feedback messages should be used, and “AVP” indicates that the
>> regular RTCP profile should be used. See also the next set of flags below.
>>
>> “should be used” does not mean that any rewritings will be done.
>>
>> I use nearly the lastest version of rtpengine on git.
>>
>> I want only to strip the encryption, in order to do test calls to http://enum-test.at/index.html ⇔ sip.nemox.net, keeping the “feedback” if it was
>> present.  The latter does not support encryption.
>>
>> Greetings
>>     Дилян
>>