AXE MSC <ainu.a...@gmail.com> writes: > After 4 minutes, handset replies back with TCP ACK. PCSCF then re-transmits > INVITE and and gets 183 back from handset. However, because calling party > side call was already cleared at 15th second, this is causing a ghost call > for B party after 4 minutes of the original call.
It is true that the called party sees a ghost call. But immediately after PCSCF receives the 183, it should send the CANCEL for the call. So if the delay was in the propagation of the INVITE to the handset, the ghost call will be canceled quickly (from the point of the view of the called party). > Can PCSCF destroy the transaction at 15th second without sending the Cancel > to handset? Later if handset comes with provisional response then PCSCF > can just reply back with SIP 481(transaction does not exist). Depending on exactly how PCSCF generates the INVITE it sends, it may be able to avoid keeping state information for the call after it is canceled. But it is still required to send a CANCEL to the called handset as soon as it receives a provisional response. However, it may be able to know that it should send the CANCEL, and be able to construct and send the CANCEL, without having kept state information about the INVITE. Dale _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
