Subject: [Enum] draft-ietf-enum-unused-00.txt

From: [email-masked]
Date: Wed, 17 Jan 2007 09:19:46 -0500

To isolate my point, let me quote the beginning of 7.2.1:

   In many countries closed numbering plans are in use.  In such a
   scheme, all valid telephone numbers have a defined length - the
   number of digits used for the subscriber number is fixed.

To me, this means a system like North America, +1, where all E.164
numbers (all subscriber numbers) have the same length (11 digits).

Dale

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From: "Stastny Richard" <[email-masked]>
Date: Wed, 17 Jan 2007 15:31:22 +0100

I have to admit that this sentence is not clear and
we will re-write it

Richard

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]
> Sent: Wednesday, January 17, 2007 3:20 PM
> To: [email-masked]
> Subject: [Enum] draft-ietf-enum-unused-00.txt
>

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From: "James McEachern" <[email-masked]>
Date: Wed, 17 Jan 2007 13:14:56 -0500

Richard, 
I agree it would be a good idea to rewrite this sentence.  While you are
at it, I suggest you look at the next sentence as well.  It currently
says:

"Thus, for a given initial digit string, the length of the subsequent
digit string together constituting a valid telephone number is known."  

The problem is that this could be interpreted as saying that for *any*
initial digit string, the length of the ... valid telephone number is
known.  Clearly this is not the case for "+441606" - but since "+441606"
is "a given initial digit string" the existing text appears to imply
that it should.

BTW, I did eventually figure out what this section was saying, but it
took a while...

Jim

-----Original Message-----
From: Stastny Richard [mailto:[email-masked]] 
Sent: Wednesday, January 17, 2007 9:31 AM
To: [email-masked]; [email-masked]
Subject: RE: [Enum] draft-ietf-enum-unused-00.txt

Richard

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From: lconroy <[email-masked]>
Date: Fri, 19 Jan 2007 12:52:43 +0000

Hi Folks,
[sorry about the delay in sending this - just got back in email range
  after the storms in Europe made life interesting]

  As the author of this particular bit of text, I apologise for the
confusion it has apparently sown.

IGNORING dialling plans and CONSIDERING ONLY number plans:-

 From my perspective, there are closed and open numbering plans.
Within closed numbering plans, there are fixed numbering plans.

The UK does not have a fixed numbering plan - it is, however, closed.
If you have a block number, you know how long the subsequent digits
will be.

I understood that the NANP has a fixed numbering plan. All digit
strings are the same length. IIUC, it appears that this is not (or
is not going to be) the case. There are or will be a mix of different
number lengths.
I stand corrected and I have learnt my new thing for today.

If there are no longer any fully fixed number plans, then we can
(happily) remove the sub-section on fixed numbering plans.

To reiterate, this whole section says nothing of the dialling
plans used - some places may choose to "optimise" the dialling plan
processed, some others may not.

In closed numbering plans, an end user gets a number of a defined
length (defined by the initial digit string - +44160650 is a different
string from +44160649). It is indeed true that the prefix +441606 does
not define the subsequent number length. That is NOT the initial digit
string I used in the examples).

I chose "initial digit string", but "prefix" would cause exactly the
same problems. It is imprecise, as closed-but-not-fixed numbering plans
can have different lengths of such prefix/initial digit strings that
define the length of the subsequent digit strings.

If anyone can think of text (other than initial digit string or prefix)
to describe clearly these variable length prefixes I (and Richard) will
be happy. E.164 doesn't do this (or other things, as Richard has already
pointed out).

all the best,
   Lawrence

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From: "James McEachern" <[email-masked]>
Date: Wed, 24 Jan 2007 21:57:24 -0500

Lawrence,
In the spirit of concrete suggestions focused on the "unused" draft, I'd
like to propose text that may clarify some of the confusion about closed
number plans.  Specifically:

Existing text:
7.2.1.  Closed Numbering Plans
In many countries closed numbering plans are in use.  In such a scheme,
all valid telephone numbers have a defined length - the number of digits
used for the subscriber number is fixed.  Thus, for a given initial
digit string, the length of the subsequent digit string together
constituting a valid telephone number is known.  All other digit strings
are invalid.

--- proposed alternate text ---
In many countries closed numbering plans are in use.  In such a scheme,
the originating system can unambiguously determine when a telephone
number is complete (i.e. when no more digits are required).  Thus, in
closed numbering plans it is always possible to identify invalid digit
strings that have too few, or too many, digits.
--- end proposed alternate text ---

It seems to me we can sidestep the whole issue of "initial digit
strings" because the essential characteristic of the closed numbering
plan is that you can always identify invalid numbers a priori.

I think the rest of section 7.2.1 can probably stand as is.

... hope this helps.

Jim

-----Original Message-----
From: lconroy [mailto:[email-masked]] 
Sent: Friday, January 19, 2007 7:53 AM
To: McEachern, James (CAR:AR00); [email-masked]
Cc: [email-masked]; Stastny Richard
Subject: Re: [Enum] draft-ietf-enum-unused-00.txt

Hi Folks,

all the best,
   Lawrence