[Freeswitch-users] Looking for a specific bug in jira - was Sonus and RFC 2833 related

Kristian Kielhofner kristian.kielhofner at gmail.com
Wed Dec 31 13:06:49 PST 2008


On 12/31/08, Anthony Minessale <anthony.minessale at gmail.com> wrote:
> In case you want to know the nitty gritty.
>
> excerpt from switch_types.h
>
> RTP_BUG_SONUS_SEND_INVALID_TIMESTAMP_2833 = (1 << 1)
>     /*
>       Sonus wrongly expects that, when sending a multi-packet 2833 DTMF
> event, The sender
>        should increment the RTP timestamp in each packet when, in reality,
> the sender should
>       send the same exact timestamp and increment the duration field in the
> 2833 payload.
>       This allows a reconstruction of the duration if any of the packets are
> lost.
>
>       final_duration - initial_timestamp = total_samples
>
>       However, if the duration value exceeds the space allocated (16 bits),
> The sender should increment
>       the timestamp one unit and reset the duration to 0.
>
>       Always sending a duration of 0 with a new timestamp should be
> tolerated but is rarely intentional
>       and is mistakenly done by many devices.
>       The issue is that the Sonus expects everyone to do it this way instead
> of tolerating either way.
>        Sonus will actually ignore every packet with the same timestamp
> before concluding if it's DTMF.
>
>       This flag will cause each packet to have a new timestamp.
>     */
>

Thanks Anthony!

-- 
Kristian Kielhofner
http://blog.krisk.org
http://www.submityoursip.com
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