It is OK that the answer uses a different payload. However, the Answer in
you example is not correct because it includes payload 96, but no "rtpmap".
Assuming the answerer wants payload 97 for telephone-event, it should look
like this:

Answer
m: audio 8000 RTP/AVP 18 0 97
rtpmap: 18 G729/8000
rtpmap: 0 PCMU/8000
fmtp:97 0-15
rtpmap:97 telephone-event/8000

cheers,
(-:bob

Robert F. Penfield
Chief Software Architect
Acme Packet, Inc.
71 Third Avenue
Burlington, MA 01803
[EMAIL PROTECTED]

----- Original Message ----- 
From: <[EMAIL PROTECTED]>
To: "SIP Implementors" <[email protected]>
Cc: "SIP IETF" <[email protected]>
Sent: Wednesday, September 07, 2005 12:57 PM
Subject: [Sip-implementors] SDP query


> Hi,
>
> Just want to know if following offer-answer exchange is correct, it has
> different dynamic payload types for DTMF and telephone events,
> is it necessary for both these to be same ?
> If they are not same, then how both parties will use these values to send
> telephone-events and DTMF digits.
>
> Offer:
> m: audio 8000 RTP/AVP 18 0 96
> rtpmap: 18 G729/8000
> rtpmap: 0 PCMU/8000
> fmtp:96 0-15
> rtpmap:96 telephone-event/8000
>
> Answer
> m: audio 8000 RTP/AVP 18 0 96 97
> rtpmap: 18 G729/8000
> rtpmap: 0 PCMU/8000
> fmtp:96 0-15
> rtpmap:97 telephone-event/8000
>
>
> Thanks,
> Udit
> _______________________________________________
> Sip-implementors mailing list
> [email protected]
> http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
>

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