Subject: [Enum] RE: Multiple service providers routing to single E.164?

From: "Pfautz, Penn L, NEO" <[email-masked]>
Date: Fri, 24 Jun 2005 08:33:16 -0400

Thilo:
In most, though not all, countries a number in the GSTN is associated
with a particular carrier and
A particular default point of interconnection for the non-VoIP world.
Thus, the "carrier of record." This is simple to identify if you do
NP via all-call-query (and let me just say that IS the  RIGHT way :-),
doubters see RFC 4041). Doesn't mean that others couldn't deliver calls
to the customer in the evolving IP world
and we see carrier/user ENUM as way to bridge the two perspectives. You
can't have interconnection if you have to
have opt-in but you want to allow for end user choice to have alternate
paths as well.
Where does that leave the third party? Probably in the user tree. Users
can agree with multiple service providers
To put NAPTR record each allowing termination through a different SP in
their Tier 2.

Penn

-----Original Message-----
From: Thilo Salmon [mailto:salmon at sipgate.de] 
Sent: Friday, June 24, 2005 5:52 AM
To: enum at ietf.org
Cc: Lind, Steven D, ALABS; Pfautz, Penn L, NEO
Subject: Multiple service providers routing to single E.164?

Penn, Steve,

can I ask you to clarify this part for me?

"The E2U+carrier record, on the other hand, is controlled by the GSTN
carrier of record for the E.164 number (i.e., the service provider who
has been allocated the block of numbers in which the number in question
is contained or to which the number has been ported)."

Apart from the difficulties for c.c.e164.arpa administratiors to verify
the PSTN routing of ported numbers in some countries, I sense another
problem:

Unlike in the PSTN world in which each number is terminated by a single
service provider this may not be the case in the voip world. The absence
of naked DSL (i.e. DSL on land lines without PSTN service) hinders
number portability as a number cannot possibly ported from a land line
without the end user loosing his or her DSL service. 

As a workaround numerous service providers have started to validate
their end users' phone numbers and route them. This development has been
boosted by CPEs which integrate FXO/FXS and SIP into a single box. Today
it is not uncommon for an end user to receive incoming routing on his or
her land line numbers through multiple service providers without any
public records of the established routing whatsoever (btw, that fact is
driving law enforcement officers nuts). In Germany alone I would expect
about one percent of all numbers to be listed in alternative routing
tables.

Where in this a shared user and carrier enum tree would you accomodate
those service providers and what would be the proposition for them?

All the best,
Thilo

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