**TABLE OF CONTENTS**

  ------------- ------------------------------------------------------ ----------
  **Section**                                                          **Page**

                                                                       

  **1**         INTRODUCTION                                           3

                                                                       

  **2**         TECHNICAL SOLUTIONS                                    4

  **2.1**       Option 1 - SBC Non-LRN Solution                        4

  **2.2**       Option 2 - AT&T LRN Solution                           5

                                                                       

  **3**         RECOMMENDATIONS                                        7

                                                                       

                                                                       

                **Appendices**                                         

                Appendix A - SBC Non-LRN Solution                      8

                Appendix B - AT&T LRN Solution                         18

                                                                       
  ------------- ------------------------------------------------------ ----------

# 1. INTRODUCTION

> 1.1 On July 2, 1996, the FCC ordered all Local Exchange Carriers
> (LECs) to begin the phased deployment of a long term Service Provider
> Local Number Portability (LNP) method in the 100 largest Metropolitan
> Statistical Areas (MSAs) no later than October 1, 1997, and to
> complete deployment in those MSAs by December 31, 1998. [^1]
>
> 1.2 The FCC directed the North American Numbering Council (NANC), a
> federal advisory committee, to make recommendations regarding specific
> aspects of LNP implementation. NANC was directed to make several
> determinations regarding the overall national LNP architecture,
> technical specifications for regional LNP databases, and selection of
> administrators to develop and manage such databases. NANC established
> the Local Number Portability Administration (LNPA) Working Group to
> review and make recommendations on these LNPA issues. The LNPA Working
> Group made a comprehensive report to NANC on April 25, 1997 which was
> released to the FCC on May 1, 1997.
>
> 1.3 The LNPA Working Group report included the LNP Architecture and
> Administrative Plan that described High Volume Call-In Networks
> (HVCI)[^2] sometimes referred to as Choke Networks. HVCIs allow
> customers with large volumes of terminating traffic for mass calling
> events such as media stimulated promotions, prize competitions, votes,
> etc. to be assigned numbers in an NPA-NXX dedicated for such use.
> Traffic for HVCIs is segregated and routed to the network via
> dedicated trunk groups that are engineered to handle limited traffic
> in order to avoid network congestion. With LNP, before route selection
> takes place, a database query is performed on calls to NPA-NXXs where
> porting is available. If HVCI numbers are portable, they would
> generate large volumes of queries that would congest signaling links
> and Service Control Points (SCPs). If HVCI numbers are ported and a
> Location Routing Number (LRN) is returned in the database response,
> the call will not be routed via HVCI dedicated trunks resulting in
> traffic congestion in regular trunk groups.
>
> 1.4 The LNPA Working Group and its subcommittee, the LNPA Architecture
> Task Force, were not able to reach a consensus recommendation to adopt
> a plan allowing for portability of HVCIs. Rather, the LNPA Working
> Group recommended further study. In the FCCs Second Report and Order
> in the matter of telephone number portability released on August 18,
> 1997[^3], the FCC urges the industry, under the auspices of NANC, to
> study the matter further and to prepare recommendations on how best to
> incorporate HVCIs into the LNP scheme.
>
> 1.5 The LNPA Working Group considered a proposal presented by
> Southwestern Bell (SBC) on October 7, 1997 that allows for porting of
> HVCI numbers without using Location Routing Number (LRN), the process
> adopted for routing calls in the network to NPA-NXXs where porting is
> available. On November 12, 1997 an alternative proposal was made by
> AT&T that uses existing technology and LRN. The alternatives were
> again discussed during the December 9, 1997 and January 8, 1998 LNPA
> Working Group meetings, on a conference call on January 16, 1998, and
> finally during the February 11, 1998 meeting when the final
> recommendation contained in Section 3 was adopted by consensus of the
> LNPA Working Group.

**2. TECHNICAL SOLUTIONS**

> 2.1 Option 1 - SBC Non-LRN Solution
>
> 2.1.1 The SBC Non-LRN solution is based on the HVCI methods currently
> used internally by SBC. Service Providers with HVCI customers open a
> pseudo NXX or the dialed choke NXX code in their end office with
> routing restrictions and establish a dedicated choke trunk group from
> the ILEC choke serving office. If a pseudo NXX is being used,
> translations at the ILEC choke serving office convert the dialed HVCI
> number to the non-dialable pseudo NXX and then utilize route indexing
> to route the call to the Service Provider's end office. Where the
> pseudo NXXs are not in use, route indexing is used to deliver the call
> to the Service Provider's end office with the dialed HVCI number. The
> SBC option is described in detail in Appendix A.
>
> 2.1.2 Option 1 Concerns
>
> A. The FCC LNP Order requires any long-term number portability method
> to efficiently use numbering resources.[^4] Both options require use
> of a new NXX, probably at the LATA level, for each new Service
> Provider offering HVCI services to new customers that are not
> currently already assigned an HVCI number. Vacant number porting would
> alleviate this concern, however, a manual process would be required.
>
> B. The FCC LNP Order requires that no unreasonable degradation in
> service quality or network reliability occur when a long-term number
> portability method is implemented[^5] and no degradation of service
> quality or network reliability when customers switch Service
> Providers[^6]. An open question remains concerning the ability of
> Option 1 to satisfy these performance criteria.
>
> C. The FCC LNP Order states that the cost recovery mechanism for LNP
> should not have a disparate effect on the incremental costs of
> competing carriers seeking to serve the same customer[^7]. Service
> Providers, therefore, want to ensure that the ILECs will provide the
> choke network facilities described in Option 1 at the same incremental
> cost as the ILEC incurs.
>
> D. The FCC LNP Order requires neutral LNPAs that are not aligned with
> any particular telecommunications industry segment to manage the
> porting process including administration of LRNs to ensure accurate
> routing of calls to ported numbers. However, Option 1 results in ILEC
> administration of routing information for HVCI networks.
>
> 2.2 Option 2 - AT&T LRN Solution
>
> 2.2.1 The AT&T LRN option builds on the existing LRN infrastructure to
> port and route HVCI traffic. Service Providers serving HVCI customers
> require a choke LRN. ILECs use existing choke codes to define LRNs and
> Competitive LECs (CLECs) use non-dialable NPA-NXXs. Use of LRNs allows
> routing of HVCI traffic on dedicated choke trunk groups.
>
> 2.2.2 Option 2 solution provides for choking before the query in order
> to protect the LNP routing data bases from calls to HVCI numbers.
> Choking is accomplished through the choke trunk between the end office
> and the tandem that launches the query, or via a loop around trunk at
> the end office for end offices that launch the query. To support
> networks that serve HVCI numbers from multiple switches, translations
> at the tandem are performed. The AT&T option is described in detail in
> Appendix B.
>
> 2.2.3 Option 2 Concerns
>
> A. The FCC LNP Order requires that no unreasonable degradation in
> service quality or network reliability occur when a long-term number
> portability method is implemented^5^. The FCC has also stated that
> they consider network reliability to be of paramount importance.[^8]
> HVCI or Choke networks were deliberately designed to isolate mass
> calling traffic from the public switched telephone network (PSTN) to
> avoid network reliability problems. Option 2 integrates this traffic
> back into the PSTN and significantly increases the risk of network
> reliability failures. It also significantly increases the complexity
> of HVCI networks by adding several processes such as loop around
> trunks and LRN query, which increase the potential for human or
> machine error which could trigger catastrophic network failures.
>
> B. Option 2 has a disparate effect on the incremental cost for an ILEC
> to serve a HVCI customer because ILECs would be required to add route
> indexing processes, loop around trunks and possibly augment SS7 links
> at each end office, as well as adding LRN database capacity in
> addition to its existing HVCI/Choke network functions. In addition in
> order to avoid querying at the tandem or choke serving office where
> aggregated HVCI trunks could generate huge query attempts, all MF
> choke trunk groups would have to be converted to SS7 to prevent
> duplicate queries from being launched at the tandem and choke serving
> offices.
>
> C. As indicated 2.1.2 A, the FCC LNP order requires any long-term
> number portability method to efficiently use numbering resources.^4.^
> It is not clear that all network elements will accept 0/1XX codes in
> an LRN since generic requirements show the LRN format as NXX-NXX-XXXX
> where N represents the digits 2-9 and X represents the digits 0-9. If
> 0/1XX codes cannot be used, Option 2 will require assignment of a
> unique HVCI NXX for every choke serving end office in every Service
> Provider's network even though those Service Providers may not serve
> any new HVCI customers that don't have an existing HVCI number.

# 3. RECOMMENDATIONS

> 3.1 The two (2) options described in Section 2 above were considered
> at the LNPA Working Group meeting on February 11, 1998. A vote was
> taken and Option 1, the SBC non-LRN solution received the consensus
> endorsement of the group. To address the concerns noted for Option 1,
> the conditions outlined in paragraphs 3.2 through 3.4 below were
> agreed upon by the LNPA Working Group membership.
>
> 3.2 Requests for modifications to the process or transition to an
> LRN-based solution may be made by any Service Provider to the LNPA
> Working Group any time following implementation of Option 1 if the
> Service Provider can provide any evidence that the current method
> fails to meet FCC performance criteria for LNP.
>
> 3.3 In support of the selection of Option 1, it was agreed that each
> Service Provider should be responsible for the provision of the
> network facilities on their side of the interconnection point for the
> choke trunk groups to the choke serving office as described in
> Appendix A. This should ensure parity in incremental costs of
> provisioning the choke trunk groups for all Service Providers. In
> addition, it was agreed that there should be no incremental charges
> over existing terminating compensation for use of the choke network to
> provide number portability.
>
> 3.4 In order to conserve numbering resources and acknowledging the
> expectation that HVCI service volumes will continue to be minimal, all
> parties agree to request that the Industry Numbering Committee (INC)
> ensure that the guidelines for the new North American Numbering Plan
> Administrator (NANPA) contain requirements for a process to facilitate
> sharing of existing and future HVCI numbering resources. If this
> process is not yet available when a Service Provider needs a number
> for a customer requiring HVCI services, consistent with the current
> uses of HVCI networks as described in paragraph 1.3, the ILECs and
> CLECs will make a good faith effort to share the existing HVCI numbers
> through a temporary process administered by the ILEC. The parties will
> work together to establish new choke NPA-NXXs when current HVCI
> numbers are exhausted.

Appendix A

SBC Presentation - Option 1

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![](media/image9.emf){width="8.501388888888888in"
height="6.043055555555555in"}

Appendix B

AT&T Presentation - Option 2

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height="6.4631944444444445in"}

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[^1]: First Report and Order and Further Notice of Proposed Rulemaking,
    cc Docket No. 95-116, July 2, 1996 (LNP Order). On March 11, 1997,
    the FCC released a First Memorandum Opinion and Order on
    Reconsideration, in which the LNP deployment periods for the first
    two (2) implementation phases were extended.

[^2]: LNPA Working Group Report, April 25, 1997, Appendix E, Paragraph
    7.13.

[^3]: Second Report and Order, cc Docket No. 95-116, August 18, 1997,
    ¶82.

[^4]: First Report and Order and Further Notice of Proposed Rulemaking,
    cc Docket No. 95-116, July 2, 1992, ¶51.

[^5]: Id. at ¶55.

[^6]: Id. at ¶56.

[^7]: Id at ¶132.

[^8]: First Memorandum Opinion and Order, cc Docket No. 95-116, March,
    1997, ¶ 83.