Thanks a lot. Now I am sure of the timer for INVITE after sending a
CANCEL request is necessary.

BR,
Johnny

On 4/30/07, Rayees Khan <[EMAIL PROTECTED]> wrote:
>
> Inline
>
> regards
> Rayees
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of johnny
> kao
> Sent: Saturday, April 28, 2007 12:30 AM
> To: [email protected]
> Subject: [Sip-implementors] Question about termination of a early dialog
>
> Hi,
>
> 1 . RFC3261 says on page 77: "Independent of the method, if a request
> outside of a dialog generates a non-2xx final response, any early
> dialogs created through provisional responses to that request are
> terminated."
>
> Does it only describe the behavior of UAS? Consider the situation below:
>
> UAC generates a CANCEL request, it could receive no responses for the
> initial INVITE request (if UAS followed the RFC2543). Thus, can I
> suppose that the early dialog of the UAC is terminated while the CANCEL
> issued?
>
> The dialog is not terminated at this point in time. It does point to
> details of the same in section 15 of RFC.
>
>
> 2. Page 54 says: "However, a UAC canceling a request cannot rely on
> receiving a 487 (Request Terminated) response for the original request,
> as an RFC 2543-compliant UAS will not generate such a response.  If
> there is no final response for the original request in
> 64*T1 seconds, the client SHOULD then consider the original transaction
> cancelled and SHOULD destroy the client transaction handling the
> original request."
>
> But the retransmission of the INVITE is stop by the provisional response
> it received, how the UAC implements this feature? Re-start the timer of
> the INVITE?
>
> Most of the servers do so. RFC 3261 does state the following
>
> "Note that both the transaction corresponding to the original request
> and the CANCEL transaction will complete independently. However, a UAC
> canceling a request cannot rely on receiving a 487 (Request Terminated)
> response for the original request, as an RFC 2543- compliant UAS will
> not generate such a response. If there is no final response for the
> original request in 64*T1 seconds (T1 is defined in Section 17.1.1.1),
> the client SHOULD then consider the original transaction cancelled and
> SHOULD destroy the client transaction handling the original request."
>
> As soon as a CANCEL request is sent a timer is started that lasts 64*T1
> to wait for 487 response for INVITE.
>
>
> THX
> Johnny, TW
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