[OpenSER-Users] mediaproxy server NEW FEATURE!!!

[Gonzalo J. Sambucaro]

Andreas,
        our local ISP´s are disconnecting DSL lines more ofthen but it
renews the IP almost instantaneously.

Regards,
Gonzalo.

> Hello,
> nice feature, i know the problem, because our local ISP´s are
> disconnecting  DSL lines every 8 hours.
> But the DSL line needs nearly 8 seconds, to be up and running again(PPP
> dialup), if i can´t hear my
> partner for a few seconds i will disconnect the line and redial, my
> opinion.
>
> Same in mobile environments, when the handover doesn´t work, saying
> "hello? - hello?" -> hangup ->
> redial.
>
> But i´m willing to try, leave me a note, where i can download your
> version.
>
> regards,
> Andreas M.
>
>
>
> Gonzalo J. Sambucaro schrieb:
>> Folks,
>>       I developed a new feature in the Media Proxy project of
>> AG-Proyect.
>> With this new feature the Media Proxy Server is now able to manage the
>> problem of the NAT IP change in an established call. It is
>> currently in production and working without any problem.
>>
>> Somebody wants to test it?
>>
>> I would like to know what to do to make this feature available to
>> everybody. Does anybody know?
>>
>> Regards,
>>
>> ------------------------------
>>
>> Details:
>> -------
>>       Supose that there is an established rtp connection between two
>> endpoints and the media proxy is in the middle doing the relay of
>> the rtp streams, let´s say
>>
>> (MP = mediaproxy)
>>
>> EP A <--------->[NAT with IP1]<-----------> MP <--------------------> EP
>> B
>>
>> EP A sends rtp to MP_IP:MP_PORT  passing through the NAT box.
>> EP B sends rtp to MP_IP:MP_PORT  without passing through a NAT box.
>>
>> The MP know that the caller = NAT_IP1:NAT_PORT1, and the called =
>> EP_B_IP:EP_B_PORT
>>
>> Now, supose that the NAT box change their PUBLIC IP from IP1 to IP2, so
>> this escenary
>>
>> EP A <------->[NAT with IP1]<---------> MP <-------------> EP B
>>
>> will change to this
>>
>> EP A <------->[NAT with IP2]<---------> MP <--------------> EP B
>>
>> so the MP should detect that change of IPs and continue relaying the rtp
>> streams but now to IP2:PORT2 instead of IP1:PORT1.
>>
>> Well, that was the situation y have experienced.
>>
>> To fix this, I developed this solution, changing rtphandler.py file:
>>
>> 1) When the first rtp packet of a source arrives, save the SSRC field in
>> the MP.
>>  - Save the SSRC of the caller.
>>  - Save the SSRC of the called.
>>
>> 2) If arrives a rtp packet with unknown source IP but with the same SSRC
>> field of some of the two streams, updates the binding (with the new IP
>> detected) between the caller and the MP or between the called and the MP
>> according to the field SSRC previously saved.
>>
>> Note: SSRC (RFC 3550 RTP),  (from the rfc: "The SSRC identifier carried
>> in
>> the RTP header and in various fields of RTCP packets is a random 32-bit
>> number that is required to be globally unique within an RTP session ")
>>
>> --------------------------------
>>
>
> --
> g,
> Andreas M.
>
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-- 
Gonzalo J. Sambucaro
Ingeniería de Software
Tel: +54-341-4230504
MSLC
gonzalo.sambucaro at mslc.com.ar
www.mslc.com.ar
Ocampo y Esmeralda - Vivero de Empresas de Base Tecnológica
Ciudad Universitaria Rosario UNR, CCT CONICET
Rosario - Santa Fé - Argentina