Hi,

One thing on min-2:

"Upstream" and "Downstream" are actually defined terms in RFC3261, and
also used in the text.

Regards,

Christer

 

> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On 
> Behalf Of Christer Holmberg
> Sent: 24. marraskuuta 2008 13:26
> To: Robert Sparks; SIP IETF
> Subject: [Sip] Sip 199-02: minors from Robert (was RE: WGLC 
> fordraft-ietf-sip-199-02)
> 
> 
> Hi,
> 
> Comments on the minor feedback from Robert.
>  
> -----
> 
> >Minor:
> >min-1) (I waffled on putting this into major): This entire 
> mechanism is 
> >an optimization, but the word optimization is never used. 
> This is (as 
> >discussed so far) ONLY an optimization and should be explicitly 
> >described as such (including documenting the limitations of the 
> >optimization).
> 
> I am not sure I disagree with you, but I am trying to figure 
> out what optimization really means in this context.
> 
> As far as the limitation is concerned, I guess that is 
> because of the fact that it is an optional feature, and that 
> it cannot be assumed that
> 199 responses will be received for all terminated dialogs.
> 
> 
> -----
> 
> 
> >min-2) The document uses "upstream" and "downstream" 
> >throughout its text. We can probably find a way to replace 
> those terms 
> >with something less likely to induce confusion especially when 
> >translating to other languages.
> 
> I think that wording has been used elsewhere, but I can use 
> something else.
> 
> 
> -----
> 
> 
> >min-3) The abstract shows the architectural confusion I call out in 
> >maj-2. Its not clear what elements use the 199 in this description.
> >The most likely interpretation of the given text is just the UAC.
> 
> Now, assuming that both forking proxies and UASs can send 
> 199, how about the following:
> 
> "This specification defines a new SIP response code, 199 
> Early Dialog Terminated, which a SIP forking proxy and UAS 
> can use to indicate upstream towards the UAC that an early 
> dialog has been terminated, before a final response is sent 
> towards the UAC."
> 
> 
> -----
> 
> 
> >min-4) The last sentence of the 5th paragraph of the 
> >Introduction (which starts "When SIP entities upstream 
> >receive") says SIP entities but talk about things that only 
> >UACs can do, specifically terminating the session startup.
> 
> When SIP entities upstream receive the non-2xx final response 
> they will
> automatically terminate the session setup
> and all associated early dialogs.
> 
> I could replace the text with the following:
> 
> "When SIP entities upstream receive the non-2xx final 
> response they will
> release resources associated with the session, and the UAC 
> will terminte
> the session setup."
> 
> 
> -----
> 
> 
> >min-5) Paragraph 1 of section 4 (Client Behavior) can be read 
> >to say a UAC MUST always insert a Supported:199. It should 
> >start with a conditional clause such as "If the client wants 
> >to receive 199 responses, then".
> 
> Correct. I'll fix that.
> 
> 
> -----
> 
> 
> >min-6) Item 5 in section 4.1 talks about dialogs being "inactive"  
> >which doesn't have meaning - I think it meant to say "the 
> >sessions associated with some early dialogs may be set to inactive".
> 
> I could replace the text with the following:
> 
> "5. Limited access resources - in case of forking and 
> multiple stream it
> may not be possible to allow early 
> media on all dialogs, so media sessions associated with some 
> dialogs may
> e.g. be set to "inactive". When a 
> dialog is terminated, media sessions associated with other dialogs can
> be allowed."
> 
> 
> 
> -----
>  
> >min-7) Section 5 should be titled "User-Agent Server" 
> >behavior to avoid confusion with Proxies.
> 
> Ok.
> 
> 
> -----
> 
> >min-8) (This will be major later in the review process if 
> >it's still there when we get there). Section 6 uses 2119 
> >capitalized words to restate requirements from other, already 
> >published and referenced, documents. This is a practice we 
> >should work hard to avoid. I suggest replacing the first two 
> >sentences with "A proxy will forward a received 199 response 
> >as it is required to forward all other non-100 provisional 
> >responses by RFC 3261." Similarly, the last paragraph of 
> >section 7 should not use 2119 capitalized words.
> 
> Ok.
> 
> 
> -----
> 
>  
> >min-9) The part of section 6 that talks about the proxy 
> >generating 199s on its own would be clearer if it were 
> >structured around the generation of multiple 199s for a given 
> >3-6xx with the case of only one 199 being generated falling 
> >out as a special case. (currently it documents the 1 final 
> >response makes 1 provisional response and calls out the 
> >multiple-199 case as an exception/extension later in the section).
> 
> How about replacing:
> 
> "When a forking proxy receives a non-2xx final response which
> terminates an early dialog and the proxy does not intend to forward
> the final response immediately (due to the rules for a forking
> proxy), and the UAC has indicated support of the 199 response code,
> the proxy MUST generate and send a 199 provisional response upstream
> for that early dialog, unless the proxy prior has received and
> forwarded a 199 response for that early dialog.  The 199 provisional
> response MUST contain a To header tag parameter, which identifies the
> early dialog that has been terminated."
> 
> ...with:
> 
> "When a forking proxy receives a non-2xx final response which 
> terminates
> one or more (if forking has occured early dialogs, and the proxy does
> not intend to forward the 
> final response immedialetly (due to the rules for a forking 
> proxy), and 
> the UAC has indicated support of the 199 response code, the 
> proxy must 
> generate and send a 199 provisional response upstream for the early
> dialog 
> on which the non-2xx final response was received. If the forking proxy
> is able 
> to identify additional early dialogs which are terminated by the same
> non-2xx 
> final response, the proxy must also generate and send a 199 provional
> response upstream for each of those early dialogs."
> 
> ...and by removing the NOTE.
> 
> I think that would make the text more clear.
> 
> 
> -----
> 
> 
> Regards,
> 
> Christer
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