Subject: [Iptel] iptel-rfc2806-01.txt

From: "Conroy, Lawrence (SMTP)" <[email-masked]>
Date: Wed, 25 Jun 2003 18:30:55 +0100

Hi Henning, folks,
   I've looked through the -01 version that I suspect will be going through
the system soon - I note that -00 has just appeared on IETF-Announce.

What I hope are my final comments on this draft in response to earlier goading:

*    ?Typo? in section 4, second bullet - what does "mandatory 
extension parameters"
      mean here? <phone-context> and <extension> parameters are 
mentioned explicitly,
      so I'm not sure what the mandatory extension parameters covers.

*    Section 5.1.4 - OK, I'll buy it - having a single context rather than a
      comma-separated list is OK.

*    Section 5.4, 1st para, 3rd/4th/5th sentence - I'm still slightly 
uncomfortable
      with "how mandatory is mandatory". The paragraph as is states 
only that the URI
      must not be used if it includes unknown mandatory parameters - a known
      but ignored mandatory parameter isn't covered.
      => Could the 3rd sentence have this text added to it, please?:
         "and MUST NOT be ignored".
      Basically, I assume that such a m-parameter is mandatory to act 
on; however,
      I have had this conversation before with others who have thought that the
      parameter needed only to be understood, but could be ignored.

*    Annex A:
Aahh...this one's tricky. If I understand the text correctly, Proxy Translation
first paragraph (third sentence) and the last paragraph (last sentence) imply
that the OBP has ->its<- local dial plan.

I use a proxy that maintains more than one context, and can select the context
based on the caller (e.g. a calling SIP AoR is classified as being in 
a particular
context, and the URI is interpreted in those terms).

Thus, in para 1, sentence 3, c/local dial plan/local dial plan logic/
Similarly, in the last paragraph, could the last sentence be replaced entirely
by something like:
"Otherwise, a provider or enterprise would have to provision each 
calling station
into an appropriate dial plan, and the OBP would have to interpret the required
destination in terms of the dial plan to which that calling station had been
associated".

Oh yes...minor typo in the last paragraph, 1st sentence: 
c/difference/different/

all the best,
    Lawrence
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From: Henning Schulzrinne <[email-masked]>
Date: Fri, 27 Jun 2003 17:55:38 -0400

Conroy, Lawrence (SMTP) wrote:

> *    ?Typo? in section 4, second bullet - what does "mandatory extension 
> parameters"
>      mean here? <phone-context> and <extension> parameters are mentioned 
> explicitly,

Mandatory extension parameters are defined in Section 5.4. I think part 
of the confusion is that 'extension' refers to both extensions in the 
telephone sense and to protocols extensions. I'll try to avoid the 
second meaning wherever possible.

>      with "how mandatory is mandatory". The paragraph as is states only 
> that the URI
>      Basically, I assume that such a m-parameter is mandatory to act on; 
> however,

I'm not sure what it means to understand something and ignore it. 
(Although I know that my son performs this feat all the time.) There may 
well be parameters that are not meaningful for a particular device. In 
that case, the device recognizes the parameter, but doesn't do anything 
observably different. I suppose you could call this 'ignoring'.

Thus, I don't see how your clarification helps.

> based on the caller (e.g. a calling SIP AoR is classified as being in a 
> particular

I'm reluctant to use the caller AOR as a dial plan selector simply 
because the same AOR can place calls from different locations within the 
same organization (same OBP). In those cases, there are two reasonable 
behaviors:

(1) Use the 'visited' dial plan;

(2) Use the home dial plan.

Forcing the use of context avoids having to guess. However, rereading 
the text, I see the need for clean up and will try to reword. I've 
reworded as

"The outbound proxy can then apply the dial plan indicated by the phone 
context in the URI" ...

Does that help?

> destination in terms of the dial plan to which that calling station had 

I hope this is now clearer without this additional sentence.