Subject: Re: [Enum] non-E.164 Numbers in ENUM

From: Mike Hammer <[email-masked]>
Date: Wed, 15 Sep 2004 15:41:37 -0400

Likewise, would a check on a number of the form:
tel:+xxxxxxxxxxxxxxxyyy...
also be considered invalid (assuming no separators, x=1-9, y=0-9)?
(+ = global-number = E.164 = 15 digits max)
Mike
At 07:58 PM 9/15/2004 +0100, Jim Reid wrote:
>>>>> "James" == Yu, James <james.yu at neustar.biz> writes:
    James> ENUM resolver (one that generates the ENUM query for a
    James> phone number) can only check if the phone number has more
    James> than 15 digits (a valid E.164# is up to 15 digits long)
    James> because it is not likely to understand the numbering plan
    James> in every country.  It won't be able to know if
    James> 1-571-434-1234-5 is a valid E.164# if it does not
    James> understand the numbering plan for country code 1.
Indeed. In fact it would be very foolish for anyone to put a priori
knowledge of a numbering plan into an ENUM resolver. Especially on an
embedded device like a handset. Numbering plans change. Pretty much
all an ENUM resolver could/should do is check that the input string
conforms to the length and legal character set defined in E.164.
_______________________________________________
enum mailing list
enum at ietf.org
https://www1.ietf.org/mailman/listinfo/enum

_______________________________________________
enum mailing list
enum at ietf.org
https://www1.ietf.org/mailman/listinfo/enum

---

From: "Yu, James" <[email-masked]>
Date: Wed, 15 Sep 2004 17:12:37 -0400

If the ENUM resolver does check the limit of 15 digits, it would block it if
it only allows valid E.164 #s.  But if it does not check, it would just
follow the RFC to formulate the ENUM query.  Whether it gets the NAPTR RRs
back depends on the info. at the Tier 2 nameservers.

James

-----Original Message-----
From: Mike Hammer [mailto:mhammer at cisco.com]
Sent: Wednesday, September 15, 2004 3:30 PM
To: Jim Reid; Yu, James
Cc: enum at ietf.org; 'Marian Durkovic'
Subject: Re: [Enum] non-E.164 Numbers in ENUM 

Mike

---

From: [email-masked]
Date: Thu, 16 Sep 2004 10:02:52 -0400

In a message dated 9/15/2004 2:59:14 PM Eastern Standard Time, jim at rfc1035.com writes:

Since the phone on my desk was made, the maximum international number length changed from 12 to 15 digits. It doesn't care about such things. So we're assuming that, in the life of an IP handset, that there will not be any other such change in E.164?

Mike

---

From: "Yu, James" <[email-masked]>
Date: Fri, 17 Sep 2004 09:28:40 -0400

Claus,

For the example you gave, I assume that the person/entity that is assigned
+49-9999-123 is also assigned +49-9999-1234.  In that case, that
person/entity only needs to register +49-9999-123 at Tier 1 Registry but it
can put entries for both +49-9999-123 and +49-9999-1234 at the Tier 2
nameservers.   

If that person/entity (ENUM Registrant) tries to register +49-9999-123 and
+49-9999-1234, there should be a requirement on the Tier 1 Registry in
Germany to handle that situation.   From the Tier 1 Registry's point of
view, it may receive the registration for +49-9999-1234 followed by the
registration for +49-9999-123 (registrations are done one by one via ENUM
Registrar) or the order can be reversed.

James

-----Original Message-----
From: claus at faerber.muc.de [mailto:claus at faerber.muc.de]
Sent: Thursday, September 16, 2004 5:40 PM
To: enum at ietf.org
Subject: [Enum] Re: non-E.164 Numbers in ENUM

Yu, James <james.yu at neustar.biz> schrieb/wrote:
> ENUM resolver (one that generates the ENUM query for a phone number)
> can only check if the phone number has more than 15 digits (a valid
> E.164# is up to 15 digits long) because it is not likely to understand
> the numbering plan in every country.

In Germany, for example, there is no numbering plan that indicates the
length of the numbers. For example, +49-9999-123 could be a complete
number while +49-9999-124 is not. With PBXes, this can even be the sole
decision of the PBX's operator.
It's even possible, although very rare, that both +49-9999-123 and
+49-9999-1234 co-exist.[1]

Further, while E.164 says that phone numbers can't be longer than 15
digits, some network or PBX operators hand out longer numbers for
"special" purposes. Those can't be reached from all around the world, of
course, but they still have their uses.

Claus

[1] In ENUM, it's possible to do that with CNAME:

$ORIGIN 3.2.1.9.9.9.9.9.4.e164.int.
@       CNAME   _
_       XXX     # entries for +49-999-123
1       XXX     # entries for +49-999-1231
2       XXX     # entries for +49-999-1232

Suddenly, you do need non-digits in the ENUM tree...
-- 
http://www.faerber.muc.de