Subject: [Enum] ENUM and service codes

From: "Clive D.W. Feather" <[email-masked]>
Date: Fri, 2 Nov 2001 09:00:50 +0000

In the UK we have a range of telephone numbers that are *not* part of E.164
number space. These are known as "service codes". While some are not really
relevant to ENUM (e.g. codes such as 132 that select an alternate long
distance carrier), some of them are. For example, the codes 11800 to 11899
will soon be in use to access directory assistance operators, and it
strikes me as reasonable for users to be able to use ENUM to get at related
services.

These numbers do not have an E.164 mapping ("+44 XXXXXX" is dialled as
"0 XXXXX", so no number not beginning 0 can be mapped back to +44). So
how do we envisage fitting these into the ENUM model ? I suppose one
possibility would be something like:

    0.0.8.1.1.service.4.4.e164.arpa

Another would be to take the whole "dialled number" concept in, so that I
get at directory assistance by:

    0.0.8.1.1.dialled.4.4.e164.arpa

and:

    0.0.dialled.4.4.e164.arpa  DNAME  e164.arpa
    1.0.dialled.4.4.e164.arpa  DNAME  1.4.4.e164.arpa
    2.0.dialled.4.4.e164.arpa  DNAME  2.4.4.e164.arpa
    ...
    9.0.dialled.4.4.e164.arpa  DNAME  9.4.4.e164.arpa

Is there any mileage in exploring this further ?

Background info for those unfamiliar with the UK numbering system. The
dialling plan works as follows:

* A full subscriber number is of the form 0NXXXX, where N is not zero.
  The split between area code and individual number is not significant
  (and varies in its placement). The number can simply be dialled. These
  numbers appear in E.164 in the form +44 NXXXX.

* Dialling 00 requests international access; it is followed by the E.164
  number, so that +33XXXX is dialled as 0033XXXX.

* Most but not all individual numbers begin with a digit between 2 and 9.
  Such numbers can be dialled within the same area code without using the
  code. Thus if I am in 020, I can dial 7XXX instead of 0207XXXX.

* Numbers beginning 1 (and also the special number 999) are service codes.
  These in turn fall into three groups:

  - Type A codes have a common meaning for all local loop operators.
    Some always route to the same place (118XX for directory), some to
    operator-specific destinations (100 for "the operator").
  - Type B codes are allocated to long distance providers, and mean
    "route the call through this provider".
  - Type C codes are operator-specific, and the same code may do different
    things for different operators.

-- 
Clive D.W. Feather  | Work:  <[email-masked]>   | Tel:  +44 20 8371 1138
Internet Expert     | Home:  <[email-masked]>  | Fax:  +44 20 8371 4037
Demon Internet      | WWW: http://www.davros.org | Mobile: +44 7973 377646
Thus plc            |                            |

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From: Jaap Akkerhuis <[email-masked]>
Date: Fri, 02 Nov 2001 12:32:20 +0100

Clive

    In the UK we have a range of telephone numbers that are *not*
    part of E.164 number space. These are known as "service codes".

Maybe I'm missing something, but, isn't enum only dealing with the
E.164 number space? To quote from the RFC:

   This document discusses the use of the Domain Name System (DNS)
   for storage of E.164 numbers.  More specifically, how DNS can
   be used for identifying available services connected to one
   E.164 number.

If you want to do something similar with ``service codes'', I think
a different RFC might be needed. Just going ahead with kludges, is
probably a bad idea.

	jaap