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

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

Hi Bob,
 
>I have few comments on draft-ietf-sip-199-06.txt. I apologize 
>if any of these are duplicates.
> 
>Section 6. The statement requiring the proxy to keep track of 
>early dialogs:
> 
>    A proxy which supports generating of 199 response codes MUST keep
>    track of early dialogs, in order to determine whether to generate a
>    199 response when the proxy receives a non-2xx final response.  In
>    addition, the proxy MUST keep track on which early dialogs it has
>    received and forwarded 199 responses, in order to not generate
>    additional 199 responses for those early dialogs.
> 
>Should precede the statement:
> 
>    If the forking proxy generates a 199 response, and if the
>    forking proxy is able to identify additional early dialogs 
>    which are terminated by the same non-2xx final response, it MUST 
>    also generate and send a 199 response upstream for each of those
early dialogs,
> 
>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.


>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.

>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.

Regards,

Christer