Subject: [Ecrit] draft-polk-dhc-uri-00: technical comment

From: "Clive D.W. Feather" <[email-masked]>
Date: Mon, 26 Sep 2005 12:13:00 +0100

I'm new to this, but I have a comment on this I-D.

Why are many of the attributes in primary/secondary pairs? This doesn't
make allowance for, say, a tertiary value while, at the same time, using up
number space to no good end.

Better would be to allow multiple URIs in the value. Contrary to 2.1 bullet
point 3, all that is necessary is to have some delimiter (say a zero octet)
between URIs. If the resulting sequence is over 255 octets, use the
concatenation mechanism.

Suppose that the URIs for two PSAPs are <sip:[email-masked]> and
<sip:[email-masked]>. The present protocol would have:

    XXX   20    1  's'
    'i'  'p'  ':'  'p'
    's'  'a'  'p'  '@'
    't'  'e'  'l'  'c'
    'o'  '.'  'n'  'e'
    't'  XXX   27    2
    's'  'i'  'p'  ':'
    'b'  'a'  'c'  'k'
    'u'  'p'  '@'  'p'
    's'  'a'  'p'  '.'
    't'  'e'  'l'  'c'
    'o'  '.'  'c'  'o'
    'm'

while I would propose:

    XXX   46    1  's'
    'i'  'p'  ':'  'p'
    's'  'a'  'p'  '@'
    't'  'e'  'l'  'c'
    'o'  '.'  'n'  'e'
    't'    0  's'  'i'
    'p'  ':'  'b'  'a'
    'c'  'k'  'u'  'p'
    '@'  'p'  's'  'a'
    'p'  '.'  't'  'e'
    'l'  'c'  'o'  '.'
    'c'  'o'  'm'

-- 
Clive D.W. Feather  | Work:  <[email-masked]>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <[email-masked]>  | Fax:    +44 870 051 9937
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Thus plc            |                            |

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From: Hannes Tschofenig <[email-masked]>
Date: Mon, 26 Sep 2005 15:32:06 +0200

hi clive,

before we jump into the details of draft proposed by james i  would like 
to see whether  the working  group  thinks that the proposal is actually 
a candidate for a  mapping protocol  (therefore competing with 
iris-econ, dns-sos and lump).

if draft-polk-dhc-uri-00.txt is not a proposal for a mapping protocol 
then we do not need to further discuss it in this working group since we 
have plenty of other topics to  finish first.

ciao
hannes

---

From: Andrew Newton <[email-masked]>
Date: Mon, 26 Sep 2005 10:57:34 -0400

On Sep 26, 2005, at 9:32 AM, Hannes Tschofenig wrote:

> before we jump into the details of draft proposed by james i  would  
> like to see whether  the working  group  thinks that the proposal  
> is actually a candidate for a  mapping protocol  (therefore  
> competing with iris-econ, dns-sos and lump).

I don't think it is.

> if draft-polk-dhc-uri-00.txt is not a proposal for a mapping  
> protocol then we do not need to further discuss it in this working  
> group since we have plenty of other topics to  finish first.

But if that were the case, then we need throw out half of the  
requirements document.  Our charter is broader than "just create a  
mapping protocol."

-andy

---

From: Hannes Tschofenig <[email-masked]>
Date: Mon, 26 Sep 2005 17:17:42 +0200

# hi andy,

Andrew Newton wrote:

>> like to see whether  the working  group  thinks that the proposal  is 
>> actually a candidate for a  mapping protocol  (therefore  competing 
>> with iris-econ, dns-sos and lump).
>
>
> I don't think it is.
>
# i went through the entire mailing list thread again and wasn't quite 
sure where this work is going.
it certainly raised many interesting discussions.

> requirements document.  Our charter is broader than "just create a  
# actually we dumped most of the requirements (both security and 
non-security requirements) already to be a bit more focused.
# i personally think that we need to get the basic work done first 
before we extend our scope. at the last ietf meeting we gave henning a 
similar feedback with regards to parts of his lump proposal where the 
protocol between mapping servers was discussed. this topic is also 
relevant for the core work of the working group but we said that we do 
not understand the requirements yet and we need to focus on the mapping 
protocol between the mapping client and the mapping server.

# ciao
# hannes

---

From: Andrew Newton <[email-masked]>
Date: Mon, 26 Sep 2005 11:42:41 -0400

On Sep 26, 2005, at 11:17 AM, Hannes Tschofenig wrote:
> # i went through the entire mailing list thread again and wasn't  
> quite sure where this work is going.

I can see how it is confusing as some people have mischaracterized  
it, intentionally or not.

>> requirements document.  Our charter is broader than "just create  
>> a  mapping protocol."
>>
>>
> before we extend our scope. at the last ietf meeting we gave  
> henning a similar feedback with regards to parts of his lump  
> proposal where the protocol between mapping servers was discussed.  
> this topic is also relevant for the core work of the working group  
> but we said that we do not understand the requirements yet and we  
> need to focus on the mapping protocol between the mapping client  
> and the mapping server.

If this is the case, then we can safely drop the following  
requirements: R7, UA-inserted, UA-referenced, Proxy-inserted, L28,  
A1a, A1c, A3, A4, and all of Section 9.

-andy

---

From: Hannes Tschofenig <[email-masked]>
Date: Mon, 26 Sep 2005 22:03:09 +0200

hi andy,

> A1a, A1c, A3, A4, and all of Section 9.
that's an important question that needs to be answered for the 
requirements and the security document. in the last few months we tried 
to remove as much as we can from the original documents to make them 
more "focused"..
it is up to us to decide how far we would like to go. i know that this 
is quite difficult and that there is certainly no single best answer.

you have been involved with all of the documents in the working group. 
what would you like to see?

ciao
hannes

---

From: Andrew Newton <[email-masked]>
Date: Mon, 26 Sep 2005 22:06:14 -0400

On Sep 26, 2005, at 4:03 PM, Hannes Tschofenig wrote:

>> requirements: R7, UA-inserted, UA-referenced, Proxy-inserted,  
>> L28,  A1a, A1c, A3, A4, and all of Section 9.
>>
>> -andy
>>
>>
> requirements and the security document. in the last few months we  
> tried to remove as much as we can from the original documents to  
> make them more "focused"..
> it is up to us to decide how far we would like to go. i know that  
> this is quite difficult and that there is certainly no single best  
> answer.
>
> you have been involved with all of the documents in the working  
> group. what would you like to see?

Hannes,

I was just pointing out an inconsistency.  And I'll note that the  
requirements milestone does not say anything about just LCMS.

Personally, I'd like us to rethink our milestones and break that  
first one out into two: a requirements document for the LCMS and a  
separate document describing the architecture and environment for the  
LCMS.  One of the problems I think this group has is that many people  
have different views on how all the pieces will fit together.

-andy

---

From: Hannes Tschofenig <[email-masked]>
Date: Tue, 27 Sep 2005 17:08:22 +0200

hi andy,

> requirements milestone does not say anything about just LCMS.
sure. when the charter was written we haven't had the same understand as 
we have it today.

> have different views on how all the pieces will fit together.
we already discussed whether it would be useful to work on an best 
current practice document describing the architecture. i got the 
impression that there was a strong agreement to have such a document.
one question is whether we have to start to work on such a document 
soon. in previous discussions (e.g. at the interim meeting) i got the 
impression that people want to work on it but certainly not now (rather 
at some time in the future).

i guess you do not suggest to work on two requirements document: (a) one 
for the lcms and (b) another one that is more generic.
rethinking about the milestones is certainly needed.

ciao
hannes