Hi Sumin,
As per my knowledge, if offer contains only codecs 0(pcma) and
101(telephone-event), answer should contain only 0 and 101 even answerer
supports 8(pcmu) and 3(GSM) these codecs should not be present in answer.
Let me know if iam wrong
Regards,
Bhanuprasad KS
----- Original Message -----
From: "Sumin Seo" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, March 12, 2007 8:54 AM
Subject: Re: [Sip-implementors] SDP Offer-Answer
correcting my questions..
**
*Can answerer add new codecs which were not present in offer to answer
SDP?*
*OR *
*Should answerer select codecs only in offer and list formats in the same
relative order they were present in the offer?*
**
Thanks.
- Sumin
On 3/11/07, Sumin Seo <[EMAIL PROTECTED]> wrote:
Hi All,
I have a question regarding on SDP offer and answer.
One of our engineers interprets rfc 3264 like below.
"rfc 3264 doesn't say that answer MUST not include more codecs which are
not in offer.
rfc 3264 also says that the answerer MAY list the formats in their
desired
order of preference.
It is RECOMMENDS that the answerer list formats in the same relative
order
they were present in the offer.
So, Session MUST be established as long as there is one common codec in
answer regardless of order of preference or existence of codecs not in
answer. "
Based on his interpretation, following negotiations should work.
Offer Answer Offer Answer
----------> --------------->
(a, b, c) (a, b ,c)
<---------- <----------------
(d, b, c, e, f) (b, c, d, e, f)
I did some interop tests with several carriers. As long as first codec in
answer is one of codecs in offer, calls are successfully connected.
*Can answerer add more codecs which were present in offer?*
*OR *
*Should answerer select codecs only in offer and list formats in the same
relative order they were present in the offer?*
Thanks in advance.
-Sumin.
_______________________________________________
Sip-implementors mailing list
[email protected]
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely
for the use of the addressee(s). If you are not the intended recipient, please
notify the sender by e-mail and delete the original message.Global Edge
Software Ltd has taken every reasonable precaution to minimize this risk, but
is not liable for any damage you may sustain as a result of any virus in this
e-mail. You should carry out your own virus checks before opening the e-mail or
attachment. Global Edge Software Ltd reserves the right to monitor and review
the content of all messages sent to or from this e-mail address
_______________________________________________
Sip-implementors mailing list
[email protected]
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
