Hi,
Marc Petit-Huguenin wrote:
Reposted, as I really would like to have a definitive answer on this.
Thanks.
I would like to have a confirmation that an UAS must be ready to receive a new INVITE in a dialog as soon a response was sent for the previous INVITE. More precisely, the UAS must not wait for the ACK before accepting the next INVITE.
My reasoning is based on the fact that RFC3261 section 14.1 says that "If there is an outgoing INVITE client transaction, the TU must wait until the transaction reaches the completed or terminated state before initiating the new INVITE." As an INVITE transaction reaches the completed or terminated state as soon a non-provisional response is received, the next INVITE can be sent at the same time the ACK for the 200 response is sent. As the packet ordering can change, the INVITE can arrive at the UAS before the ACK. So this mean that the server should be prepared to receive the next INVITE before receiving the ACK.
Completed State for client-invite is reached only when the response was 3xx-6xx, and not any non-provisional response (I mean 200 ).
As per section 13.3.1.4 , 2xx retransmission is handled by UA core.A 2xx response is passed to Transport layer periodically, for all protocols, until an ACK is received. This retransmission starts at T1 seconds, and doubles until it reaches T2 seconds.
Finally if the there is no ACK, session SHOULD be terminated, by sending a BYE.
So Answer to your question : UAS must wait for an ACK, before accepting any request within the dialog.
Is it correct?
Thanks.
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