[SIPForum-discussion] Codecs in 200 OK response

Keyur Amin fossil0681 at yahoo.com
Mon Oct 7 22:49:53 UTC 2013


Yes, it is allowed to send multiple codecs in 200 OK. Please refer to http://www.ietf.org/rfc/rfc3264.txt.

Regarding a=X-sqn, those seem like temporary/proprietary headers inserted by the UA, does not mean anything in terms of call context. 
Keyur Amin



 From: Waqas Arshad <waqas.arshad000 at yahoo.com>
To: "discussion at sipforum.org" <discussion at sipforum.org> 
Sent: Monday, October 7, 2013 1:39 AM
Subject: [SIPForum-discussion]  Codecs in 200 OK response


Can someone please confirm if the SDP of 200 OK (in response to an INVITE) can contain multiple codecs in m-line or it should have only one codec at which B party has responded to establish the connection. e.g.

m=audio 39838 RTP/AVP 0 8 18 101
a=rtpmap:0 pcmu/8000
a=rtpmap:8 pcma/8000
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15

200 OK SDP:
m=audio 18238 RTP/AVP 0 101
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=X-sqn: 0
a=X-cap: 1 audio RTP/AVP 100
a=X-cpar: a=rtpmap:100 X-NSE/8000
a=X-cpar: a=fmtp:100 200-202
a=X-cap: 2 image udptl t38 

So can 200 OK SDP contain m-line as below too or just one codec at which call is going to be established???

m=audio 18238 RTP/AVP 0 8 18 101

Secondly, can someone please suggest the meaning of a=X-sqn in above 200OK?

Thanks in advance.
This is the SIP Forum discussion mailing list
TO UNSUBSCRIBE, or edit your delivery options, please visit http://sipforum.org/mailman/listinfo/discussion
Post to the list at discussion at sipforum.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sipforum.org/pipermail/discussion/attachments/20131007/92096ff5/attachment-0002.html>

More information about the discussion mailing list