**North American Numbering Council**

c/o Columbia Institute for Tele-Information

Columbia Business School

1A Uris Hall

3022 Broadway

New York, NY 10027-6902

July 25, 2005

Mr. Thomas J. Navin

Chief, Wireline Competition Bureau

Federal Communications Commission

445 Twelfth Street, S.W.

Washington, D.C. 20554

RE: Request for FCC Endorsement of LNPA N-1 Architecture Recommendation

Dear Mr. Navin:

The purpose of this letter is to urge the Commission to endorse a
recommendation made by the NANC's Local Number Portability
Administration Working Group (LNPA WG) for determining which service
provider is responsible for querying number portability databases,
particularly with respect to Extended Area Service (EAS) calls. Such an
endorsement should eliminate or at least substantially mitigate
confusion and disputes over this responsibility.

The recommendations were made by the LNPA WG in January, partly in
response to a request from the Bureau's staff for the NANC's advice on
this matter. Unfortunately, due to a clerical error on my part I have
not forwarded the recommendations until today. I apologize for the
delay.

As background, a carrier involved in establishing a telephone connection
must query a local number portability database to determine which
carrier is responsible for finally terminating the call to the ported or
pooled telephone number being called. Typically, the carrier before the
final terminating carrier (the so-called "N-1 carrier") is responsible
for making the database query. As an example, for a local call the
originating carrier is also the N-1 carrier and is responsible for
performing the query in its network or contracting with another entity
to perform the queries on its behalf. Similarly, for interLATA toll
calls the interexchange carrier is the N-1 carrier and is responsible
for performing the necessary query.

The LNPA WG had been working on extensive guidelines for the overall N-1
Architecture when the Commission staff specifically requested the NANC
to review the N-1 process for Extended Area Service (EAS) calls. The
LNPA WG's full report, which is attached for your information, was
forwarded to telecommunications service operators by the trade
associations represented on the NANC.

With respect to EAS, the LNPA WG's recommendation, included on page 11
of the full report, is as follows:

-   *On intraLATA calls to EAS codes, the originating carrier is the N-1
    carrier and is responsible for the query on all calls to portable
    EAS codes.*

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-   *In cases where the originating carrier's switch supports the
    function to route interLATA EAS calls to ported numbers as a local
    call via an interLATA LRN, and trunking to all potential final
    destinations (or their POIs in the EAS area) have been established,
    the query will be performed in the originating switch.*

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-   *On interLATA calls to EAS codes where the originating carrier does
    not support the function to route the call as a local call to ported
    numbers via an interLATA LRN, the donor carrier in the terminating
    LATA performs the role of the N-1 carrier (i.e does the database dip
    and routes the call to the switch serving the ported number). In
    this instance, the donor carrier will perform the LNP query in the
    terminating LATA in either that carrier's donor end office or
    terminating LATA tandem, whichever terminates trunks from the
    originating LATA on calls to EAS codes. (Note that the terminating
    LATA tandem case is only applicable if the donor carrier has a
    tandem in the terminating LATA, and all switches in the originating
    LATA that can place local calls to the EAS codes in the terminating
    LATA have trunking to the tandem in the terminating LATA per
    mutually accepted interconnect agreements.) The originating carrier
    is responsible for compensation to the donor carrier for performing
    the N-1 database dip function.*

> *The donor carrier in the terminating LATA may charge the originating
> carrier for transit (consisting of transport and switching) of the
> call.*
>
> *This language takes into account current technical limitations and
> regulatory constraints as well as existing configuration issues.
> Carriers may consider making modifications to their querying and
> routing arrangements as technology upgrades and changes to
> interconnecting configurations permit.*

To minimize problems and disputes with respect to database query
responsibilities, I recommend, on the NANC's behalf, that the Commission
endorse all of the LNPA WG's recommendations (particularly the EAS
proposals) and, as quickly as possible, take any other steps that may be
necessary to encourage service providers to abide by them.

Please feel free to contact me if you or members of your staff have any
questions.

Sincerely,

/Signed/

Robert C. Atkinson

NANC Chair

Attachment

cc: Regina Brown, FCC

Marilyn Jones, FCC

Lisa Gelb, FCC

Narda Jones, FCC

Cheryl Callahan, FCC

NANC Members