Thank you. Hence Asterisk 1.4.29 has a problem...How can I correct it? For more detail I have attached the SIP-SDP negotiation.<br><br><div class="gmail_quote">2010/2/8 Olle E. Johansson <span dir="ltr"><<a href="mailto:oej@edvina.net">oej@edvina.net</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><br>
8 feb 2010 kl. 02.18 skrev Kevin P. Fleming:<br>
<div class="im"><br>
> Salvatore Frandina wrote:<br>
><br>
>> I'm using SIPp program to make a call toward Asterisk PBX. The SIP call<br>
>> works well with Asterisk 1.6 (1.6.0.x, 1.6.1.x and 1.6.2.x) but not with<br>
>> Asterisk 1.4.x. After I have analyzed the sip message between SIPp and<br>
>> Asterisk 1.4.29 I have discovered a discrepancy in SDP message.<br>
>> The RTP payload type is different: SIPp sends 96 dynamic payload type<br>
>> for H263-1998 - H264 while Asterisk response 103 dynamic type for<br>
>> H263-1998 - H264. Why? With the other versions there are not problems.<br>
><br>
> SDP offer/answer does not require that both ends use the same payload<br>
> type numbers for matching payloads; they can differ and it's perfectly<br>
> acceptable. This is not an error.<br>
><br>
</div>RFC 3264:<br>
<br>
" In the case of RTP, if a particular codec was referenced with a<br>
specific payload type number in the offer, that same payload type<br>
number SHOULD be used for that codec in the answer. Even if the same<br>
payload type number is used, the answer MUST contain rtpmap<br>
attributes to define the payload type mappings for dynamic payload<br>
types, and SHOULD contain mappings for static payload types. The<br>
media formats in the "m=" line MUST be listed in order of preference,<br>
with the first format listed being preferred. In this case,<br>
preferred means that the offerer SHOULD use the format with the<br>
highest preference from the answer.<br>
"<br>
<br>
As a developer, we should tread SHOULD treat SHOULD as a MUST, remember :-)<br>
<font color="#888888"><br>
/O<br>
</font><div><div class="h5"><br>
--<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br>_______________________________________<br>Salvatore Frandina<br>website: <a href="http://frandinas.altervista.org">http://frandinas.altervista.org</a><br>mail: <a href="mailto:salvatore.frandina@gmail.com">salvatore.frandina@gmail.com</a><br>
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