Hi,
Query Regarding Connection lines in SDP
Related RFC 2327 & 3264
Scenario-->
There are two Sip Endpoints, both of which put connection lines
information at the media level rather than at the session level.
In the case when offer in the Invite is generated to the other endpoint
there are two media streams and both of the these have corresponding
connection line ("c="). The other endpoint supports only one of the media
stream so it sends "m=audio 0 RTP/AVP 7" and the other accepted media
in the answer.
Question -->
So the question is whether there should be connection line for the rejected
media stream as well has there is no session level connection line present.
If yes than what is the use of the information in the connection line.
Relevant text from the RFC is below for reference
Text from RFC 2327 Section 6 "Sdp Specification"
\*
A session announcement must contain one "c=" field in each media
description (see below) or a "c=" field at the session-level. It may
contain a session-level "c=" field and one additional "c=" field per
media description, in which case the per-media values override the
session-level settings for the relevant media."
*/
Text from RFC 3264 Section 6 "Generating Answer"
\*
For each "m=" line in the offer, there MUST be a corresponding "m="
line in the answer. The answer MUST contain exactly the same number
of "m=" lines as the offer. This allows for streams to be matched up
based on their order. This implies that if the offer contained zero
"m=" lines, the answer MUST contain zero "m=" lines.
*/
Regards
Saurabh
Saurabh Gupta - HSS Bangalore Campus
*********************** HSS-Private ***********************
"DISCLAIMER: This message is proprietary to Hughes Software Systems Limited
(HSS) and is intended solely for the use of the individual to whom it is
addressed. It may contain privileged or confidential information and
should not be circulated or used for any purpose other than for what it is
intended. If you have received this message in error, please notify the
originator immediately. If you are not the intended recipient, you are
notified that you are strictly prohibited from using, copying, altering, or
disclosing the contents of this message. HSS accepts no responsibility for
loss or damage arising from the use of the information transmitted by this
email including damage from virus."
_______________________________________________
Sip-implementors mailing list
[email protected]
http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
