Re: [Sip] Should early dialogs be dropped when 2xx is received???

["Christer Holmberg" <christer.holmberg at ericsson.com>]

Hi, 

>>The UAC core considers the INVITE transaction completed 64*T1 seconds
>>after the reception of the first 2xx response.  At this point all 
>>the early dialogs that have not transitioned to established dialogs
are
>>terminated.  Once the INVITE transaction is considered completed by
>>the UAC core, no more new 2xx responses are expected to arrive.
>
>>Thus the other early dialogs will linger for 64*T1 seconds.
>
>Right, this is true if the UAC wants to have multiple final dialogs.
>
>If it does not, then I do not think the UAC has to wait for 64*T1
seconds. It can terminate early dialogs by sending a BYE with
appropriate to-tag corresponding to the early dialog leg, that it 
>wants to terminate.

Correct. Or, it could keep enough state in order to send ACK+BYE if/when
it receives additional 200 OK responses (which I think is going to be
quite rare in the first place).

Regards,

Christer




>If the UAC does destroy all the other early dialogs, then it would need

>to be able to handle any additional 2xx responses for unknown dialogs, 
>presumably by sending an ACK immediately followed by a BYE. This is 
>really the same case as an additional 2xx response arriving for a brand

>new dialog (i.e.
>the UAC never received a 1xx).
>
>cheers,
>(-:bob
>
>-----Original Message-----
>From: sip-bounces at ietf.org [mailto:sip-bounces at ietf.org] On Behalf Of 
>Paul Kyzivat
>Sent: Tuesday, August 05, 2008 10:16 AM
>To: Christer Holmberg
>Cc: SIP IETF
>Subject: [Sip] Should early dialogs be dropped when 2xx is received???
>
>The following in the discussion of 199 issues reminded me of a question

>I have had for a long time. I'm changing the subject because it isn't 
>directly pertinent to the 199 discussion.
>
>Christer Holmberg wrote:
>
>> What I mean to say is that when the UAC receives a final
>response for
>> an early dialog it normally releases all other early dialogs
>(the UAC
>> should of course still be ready to accept 200 OK responses for other 
>> dialogs).
>
>This has always been a fuzzy area to me. If the UAC is prepared to 
>retain multiple final dialogs if they happen, is it still expected to 
>release early dialog state for other dialogs when it receives the first

>2xx? That could mean that subsequent 2xx responses can't be turned into

>viable dialogs because state has been lost. (E.g. if preconditions were

>being negotiated during the early dialog.)
>
>Shouldn't the rule be that *if* the UAC is only intending to retain the

>first final dialog then it should/may abandon all other early dialogs 
>when it receives a 2xx, but if it might want to keep additional dialogs

>if additional 2xx responses are received, then it ought not drop the 
>early dialogs?
>
>        Thanks,
>        Paul
>
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