Hello All,
I have very basic question regarding the codec negotiation in SIP, I will try
to summarize my queries below -
1) If A is initiating the call and sending the supported codec list say (1,2,3)
A --> INVITE (SDP-> audio 1 2 3) --> B ( B supports 1 , 3, 5)
A <-- 200 OK ( SDP -> what will be here 1, 2 ,3 OR 1, 3, 5) <-- B
if it is 1, 3, 5 then what will be the response to B ??
2) If A is initiating the call and sending the supported codec list say (1,2,3)
A --> INVITE (SDP-> audio 1 2 3) --> B ( B supports 2 , 3, 5)
A <-- 200 OK ( SDP -> what will be here 2 , 3 OR 2 , 3, 5) <-- B
if it is 2 , 3 then what will be the response to B ??
if it is 2 , 3, 5 then what will be the response to B ??
3) If A is initiating the call and sending the supported codec list say (1,2,3)
A --> INVITE (SDP-> audio 1 2 3) --> B ( B supports 4, 5,6)
A <-- 200 OK ( SDP -> what will be here ??) <-- B
and what will be the d behaviour of A ....
4) Re-Negotiation -
If A is initiating the call and sending the supported codec list say (1,2,3)
A --> INVITE (SDP-> audio 1 2 3) --> B ( B supports 1 , 2, 3)
A <-- 200 OK ( SDP audio1, 2 ,3 <-- B
A --> ACK --> B
( I guess the rtp will use codec 1)
Now during the call say A wants to change the codec to 2, will it send the
re-invite or SDP session has some provision for it( I just want to confirm, is
it possible to change the codec without sending any SIP message)
PS: I know i have made a lengthy mail, but it is very much required for me to
understand some network behaviour and implementation.
Regards
Atul
_______________________________________________
Sip mailing list https://www.ietf.org/mailman/listinfo/sip
This list is essentially closed and only used for finishing old business.
Use [email protected] for questions on how to develop a SIP
implementation.
Use [email protected] for new developments on the application of sip.
Use [email protected] for issues related to maintenance of the core SIP
specifications.
