ms6b#@ANDREW.CMU.EDU.UUCP (02/23/87)
1.
@begin{indent} . . . Among the problems it is currently wrestling with: how
will
ISDN telephone numbers be assigned? . . .
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Why can't they use the same numbering system as the rest of us?
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As I noted in my earlier message, they can use the same 10 digit format, the
issue is one of assigning area codes to ISDN service providers or exchange
numbers within area codes. The problem arises because, at present, 10 digit
telephone numbers are not drawn from a flat address space like Ethernet
numbers, but rather are hierarchically organized in order to provide routing
information (like internet addresses). The problem is how to indicate that
the destination number is on a particular carrier's ISDN network by
inspecting only the area code or only the exchange, and not by requiring a
10 digit translation.
At present carrier information (for long distance) is either implied by
default (presubscription) or specified by use of an additional 5 digits
(10XXX). When it becomes necessary to also specify a destination carrier
(e.g. AT&T primary rate access bypass versus the BOC's ISDN), one would like
to do so without adding to the number of digits users must dial.
2.
@begin{indent}Will there be any attempt to be more flexible? For example:
1. Variable length area codes and telephone numbers with longer codes
and shorter numbers for remote areas. This cuts down on the amount
of dialing required in those areas and makes it easier to use the
allowed codes. The total length could be fixed at say, 11
digits.@end{indent}
The French used to have the scheme you describe and they have just switched
away from it. An important advantage of uniform 7 digit numbers is that you
know, when someone gives you his telephone number, whether or not you wrote
all of it down. With variable length numbers you are never sure unless you
know the area code, or that "telephone numbers in Montpelier, Vermont are
always 5 digits" That is much too confusing for human beings.
Besides, as more and more instruments/PBXs come equipped with speed dialing,
the major opportunities for shortening the dialing sequence (with frequent
callees) will be exhausted by changes to CPE rather than to the numbering
scheme. The issue is similar to the argument over whether alias's should be
allowed in the domain name data base, or whether short aliases are something
to be provided by the user's local system.
3.
I first heard about the issue in the meetings of ANSI T1D1.1 which is
developing service standards for the ISDN. TID1.1 turned the issue over to
the "ISDN Numbering Forum" organized by Bellcore as manager of the NANP.
Information about the NANP and ISDN can be obtained from Mr. Gary Fleming of
Bellcore's Carrier Interconnection and Numbering Plan Organization at (201)
740-4597.
The minutes of the ISDN Numbering Forum meetings can be obtained from
District Manager - Information Exchange Managment
Technology Systems
Bell Communications Research
435 South Street Rm. 2K-122
Morristown, NJ 07960-1961
(201) 699-5800
I recommend the Bellcore Digest as a means of keeping abreast of Bellcore
activities and publications.