[Serusers] Re: [Asterisk-Users] INFO/DTMF retransmissions in * not absorbed?

Andres andres at telesip.net
Sun Feb 22 19:52:20 CET 2004

Hi Jiri,

Been there.  We switched from INFO to RFC2833 for this same reason.  
Take a look at:

Not only retransmissions are affected but out of order packets too.  
This behaviour can be partly blamed on the RFC:

"In addition, the INFO method does not define additional mechanisms
for ensuring in-order delivery. While the CSeq header will be
incremented upon the transmission of new INFO messages, this should
not be used to determine the sequence of INFO information. This is
due to the fact that there could be gaps in the INFO message CSeq
count caused by a user agent sending re-INVITES or other SIP
messages. "


Jiri Kuthan wrote:

>I'm wondering whether people know if there could be a problem
>with * receiving retransmissions of INFO/DTMF requests.
>I'm trying to play DTMF via INFO to *. If it takes a 200 reply too 
>long to come back, the request is retransmitted. Whenever this
>happens, the IVR down in PSTN reports that the number sequence
>is incorrect.
>This makes me guess that * turns INFO retransmissions into new
>DTMF digits on the PSTN part.
>Does anybody have the same experience? Is it a known problem? 
>Are there any patches?
>Jiri Kuthan            http://iptel.org/~jiri/ 
>Asterisk-Users mailing list
>Asterisk-Users at lists.digium.com
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