Re: [Sip] Comments on draft-ietf-sip-199-00.txt

["Christer Holmberg" <[e-mail]>]

Hi, 

>>7) Section 7: "A UAC that receives a 199 response for an early dialog
MUST NOT
>>send any further requests on that dialog...". Can you point to any
list discussion
>>around this requirement? I think there's some danger to consider
there. At the
>>very least we need to make this statement multiple-usage safe.
>
>This is a very good catch. This needs to be aligned with dialogusage.
If the 199 contained the final response that triggered it, then that
final response could be used to determine the impact 
>on the dialog or dialog usage or just the transaction. But if the 199
doesn't contain the final response, then this is a problem.

I forgot to bring this issue up in Dublin. Sorry for that.

First, we need to remember that the UAS may terminate every dialogusage
when sending the final response (depending on what final response is
sent), without the UAC knowing it. And, due to the forking rules, the
final response which is sent to the UAC may not even be the same which
was sent by the UAS, if a final response from another UAS is chosen as
the "best".

Second, we need to remember that this only affects early-dialogusages.

If needed, I guess we could include the final response which triggered
the 199, but we could also simply say that if the UAC does not know to
which dialogusage (if there are many) the 199 applies, it should not do
anything which may affect other usages for the same early dialog.


>>12) The open issue in section 10 (can we get a proxy involved in 
>>sending its own 199 reliably) is a big part of the confusion I pointed
to at 
>>the beginning of these comments. This is the part of the draft that I
expected 
>>needing face time in Dublin, but maybe we can make enough progress on
it in the 
>>hallway.
>>I don't think there's any way to allow it, and what we'll need instead
is text
>>more strongly recommending the endpoints do this themselves and 
>>restrict any proxy genesis of 199s to the unreliable case (and explain

>>more that this is just a transitionary optimization - we _really_ want
the 
>>endpoints doing this work if anything's going to be doing it at all.
>
>If the "proxy" wants to send a reliable 199, then I think it needs to
do so on its own dialog. But that makes no sense. Having the proxy
attempt to send the reliable response on the dialog 
>belonging to the UAS is *insane*.

Let's discuss this in the "open issues" thread.

Regards,

Christer
_______________________________________________
Sip mailing list  https://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [e-mail] for questions on current sip
Use [e-mail] for new developments on the application of sip