[SIPForum-discussion] A offer/answer in Re-INVITE

[=?gb2312?q?=D3=EA=20=B3=C2?=]

Hi,
  Could you please advise ?
  Is the SDP description in Re-INVITE accepted by the callee ROSE?
   
  Here is the call flow:
  BOB          ROSE
  -------------------¨¤ INVITE (offer)
  <-------------------  100 
  <-------------------  180 (answer)
  <-------------------  200
  -------------------¨¤ ACK
  <-------------------  RE-INVITE 
  -------------------¨¤ 100
  -------------------¨¤ 200 (offer)
  <-------------------  ACK
  -------------------¨¤ BYE
  <------------------- 200
   
  As we can see, in the RE-INVITE transaction, BOB providing an offer in 200,and he change the codec in SDP description (like switch form 96 to 97),but there is no answer from ROSE. 
   
  According to RFC3261, section 14.2 UAS Behavior provide offer in 200 means ¡±This is to avoid the need for the peer to reject the session description¡±,but I am not sure whether is possible in reality¡­
   
  Any answer is available!
   
  Thx
   
  Nora

       
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