Re: telephone URLs, comments on draft-antti-telephony-url-04

Larry Masinter (masinter@parc.xerox.com)
Tue, 30 Jun 1998 01:36:52 PDT


From: "Larry Masinter" <masinter@parc.xerox.com>
To: "=?iso-8859-1?B?UGF0cmlrIEbkbHRzdHL2bQ==?=" <paf@swip.net>,
Cc: <uri@Bunyip.Com>, <eva@nic-se.se>
Date: Tue, 30 Jun 1998 01:36:52 PDT
Message-ID: <000c01bda402$3b466180$15d0000d@copper-208.parc.xerox.com>
In-Reply-To: <v04011700b1be4027d62b@[192.168.111.27]>
Subject: RE: telephone URLs, comments on draft-antti-telephony-url-04

> That is because of an _administrative_ choice! If the hostname changes, the
> filenames does not change. When an area code change, the phone numbers do,
> by definition, but maybe to the same number within the new area. There _IS_
> a difference between these two cases Larry!

> You obviously don't understand my arguments in difference, and that you say
> that renumbering can be ignored is a slap in the face to the people working
> with these issues which have spent not a few hours thinking about this
> problem.

Patrik, I don't understand your argument, you're right. I don't understand
what is different between:

  "When an area code changes, the phone numbers do, by definition
    but maybe to the same number within the new area"

and

  "When the host name changes, the URLs do, by definition
    but maybe to the same path with the different hostname"

But I'm not trying to slap anyone in the face by making such a claim,
nor am I asserting that 'renumbering can be ignored'. I was saying
'hierarchy is useful even if it doesn't support renumbering'. This isn't
a way of insulting others who are thinking about the issue. I would say,
if it is any consolation, that I will gladly match the hours I've spent
thinking about the issue with anyone else

> Phone numbers are allocated individually. A standard exists in how to write
> and format a phone number. The phone equipent locally know what "base" it
> has and how to convert a number according to the International standard
> into what has to be signalled on the wire. End of story.

The standard for 'how to write and format a phone number' doesn't
embed directly into the URL syntax; some amount of translation is
necessary. We're trying to decide how much translation is necessary
or useful. The standard for 'how to write and format a phone number'
is actually several standards, for global numbering, local numbering,
and one other, with several options for dial strings and tones and
punctuation. As long as we're considering the punctuation around
the translation for telephone number to URL syntax, it is useful to
consider the cost and benefit around substituting "//" for "+" and
"/" for punctuation around natural delimeters between country code
and the rest of the phone number, and, for those locations that have
them, the delimeter between area/city code and the rest of the number.

I was making a case for the benefits, which, albeit minor, are there.
As you say, it doesn't help with renumbering, but helps in some cases
with 'want to specify local phone number without giving country code
or area code, but explicitly default them from the context'. In any
of the proposals, we need some syntax to separate 'local telephone
number, default country and area code' and 'local dial string, including
PBX access codes', but using the "//" and "/" notation, it's pretty
clear: "//<n>/" is a country code, "///" means 'country code elided',
and "//[n]//" means "area/city code elided"; tel://local/1234 could
be used to mean "local dial string", and other contexts could easily
be defined. 

The alternative tel:+nnnnnn notation doesn't have a natural way to
name the context for local dial strings. Using a parameter seems awkward,
since it isn't really a parameter of the reference, or even a 'scope',
it is a context of interpretation (or, in the URI syntax, a naming
authority.)

So I'm not sure what the "end of story" is. draft-antti-telephony-url-05
doesn't distinguish between "local-phone-number" and "global-phone-number
with some components elided". When someone in the local area quotes
'my phone number is 812-4333', this isn't really the number I dial,
but rather, I infer the context of interpretation from the conversation.
In some other cases, the number quoted _is_ a local dial string, but
it is usually explained that way.

It would be useful if the URL scheme for telephone number supported
the kind of telephone numbers that people normally use in day to day
discourse, are printed on business cards, etc.

Personally, I think using the "//" notation for the naming authority,
with a country code as the default naming authority for global-phone-number,
would be a good use of the generic URL syntax and allow for a clearer
expression of a wider variety of telephone numbers and numbering plans.

I'm willing to consider other syntactic conventions, too, 
fax://local/4333 for local numbers, but fax:+1-650-812-4333 for global
phone, but at least it is worth a _try_ to be clear.

Larry