2011/7/26 Leo Leo <[email protected]>:
> But, as you assure correctly, the BYE may be used in this case, as writen in 
> RFC, section 15:
>
> "The BYE request is used to terminate a specific session or attempted 
> session. In this case, the specific session is the one with the peer UA on 
> the other side of the dialog. (...). The caller’s UA MAY send a BYE for 
> either confirmed or early dialogs, and the callee’s UA MAY send a BYE on 
> confirmed dialogs, but MUST NOT send a BYE on early dialogs."
>
>
> Thanks for the answer!

Hi Leo, right, I missed to point such exact section of the section 15
(I didn't find it, sorry).

Anyhow, all this topic is a bit contradictory since a dialog (which
means answered-dialog or early-dialog) requires all the stuff for
constructing a dialog, which is:

a) A remote target (which is the Contact of the other participant).
b) A route-set (if present) which is constructed by mirroring
Record-Route headers inserted by proxies.

Both a) and b) are just required by RFC 3261 for ***reliable***
responses. In RFC 3261 the only reliable response is a 2XX. So we
could state that RFC 3263 (PRACK) is required so 180/183 can also
become reliable responses (so they MUST satisfy points a) and b)
above, so PRACK and BYE can be sent to the specific destination).

BTW I've never seen a BYE for terminating an early-dialog :)

In fact, I don't know how the flow should be, this is:

   alice                bob

   INVITE ---------->
   <---------------- 180 (INVITE)
   PRACK --------->
   <----------------- 200 (PRACK)
   BYE ------------->
   <----------------- 200 (BYE)

After the 200 (BYE) should the UAS send a final response (i.e. 487)
for terminating the INVITE transaction (in the same way a CANCEL
triggers a 487 for the INVITE from the UAS and the corresponding ACK
from the UAC)? I'm not sure about it.


Regards.

-- 
Iñaki Baz Castillo
<[email protected]>

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