Re: [Sip] I-D Action:draft-ietf-sip-199-06.txt

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

Hi Bob, 

>>>In fact, if the proxy is keeping track of early dialogs, under what 
>>>circumstances would it not be "able to identify additional early 
>>>dialogs which are terminated by the same non-2xx final response"?
>>
>>Just because the proxy keeps track of early dialogs, it doesn't 
>>necessarily know that an error response on early dialog X also 
>>terminates early dialog Y. In order to know that, the forking proxy 
>>needs to know that early dialogs X and Y come from the same forking 
>>proxy further down the path.
>>
> 
>Of course it can. If the proxy forwarded the request to Z, 
>and Z forked to X and Y, the provisional responses from X and 
>Y that created the early dialogs would have the same 
>branch-id. The error response from Z would have that same 
>branch-id. The proxy would know that all early dialogs 
>created by a 1xx with that branch-id would have terminated 
>(i.e. both X and Y).

But, the branch-id is part of the Via, which is removed by each entity
when forwarding the response. So, the forking proxy is never going to
get the branch-id inserted by Z, is it?


>>>Section 8 (199 Early Dialog Terminated) seems out of place.
>>>Shouldn't this be in the introduction? or in an "Overview Of 
>>>Operation" between sections 3 and 4?
>>
>>I have tried to use other similar drafts as "template".
>>
>>
>>>The text in Section 9 (Usage with SDP offer/answer) should be in 
>>>section 5 (User Agent Server behavior).
>>
>>I think it is good to have a separate chapter. Of course, I could
refer 
>>to chapter 9 from chapter 5.
> 
>My point is that all too often behavior requirements (MUST, 
>SHOULD, MAY, etc.) get buried is separate sections and folks 
>can miss them. If all the requirements are in the applicable 
>"behavior" section, they are easy to find and developers are less
likely 
>to miss them. If you want it to be a separate section, make 
>it 5.1. All UAS requirements should be in section 5 or a 
>subsection thereof.
>
>>>The statement in section 10 recommending that the UAS send
>>>199 unreliably should be in section 5.
>>>
>>>The statement in section 10 forbidding proxies from sending
>>>199 reliably should be in section 6 (Proxy behavior).
>>
>>Same as for offer/answer.
>>
>>Since the 199 procedures related to offer/answer and reliable
responses 
>>are special, I think it is good to have specific chapters for it.
>> 
>The requirements/restrictions for reliable provisional 
>responses are very important. They could easily be missed by 
>having them in a separate chapter in the back of the 
>document. Again, all UAS behavior requirements should be in 
>section 5 (or sub-section) and all proxy behavior 
>requirements should be in chapter 6 (or sub-section).

I'll think of something. But, as you ok with the text as such? It's only
the location of the text which you have an issue with?


Regards,

Christer