Method for routing a call

• US 5,796,813 A
• Filed: 08/08/1996
• Issued: 08/18/1998
• Est. Priority Date: 06/30/1995
• Status: Expired due to Fees

• Current Assignee: Siemens Telecom Networks (Siemens AG)
• Original Assignee: Siemens Telecom Networks (Siemens AG)
• Inventors: Sonnenberg, Edward
• Primary Examiner(s): Zele, Krista
• Assistant Examiner(s): Wolinsky, Scott
• Application Number:
  US08/694,380
• Time in Patent Office: 740 Days
• Field of Search: 379/221, 379/207, 379/201, 379/219, 379/220, 379/211, 379/210, 379/127, 379/265, 379/112, 379/114, 379/115, 379/229
• US Class Current: 379/221.13
• CPC Class Codes: H04M 3/42297 with number portability
• CPC Class Codes: H04Q 2213/13097 Numbering, addressing
• CPC Class Codes: H04Q 2213/13102 Common translator
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/13141 Hunting for free outlet, circuit or channel
• CPC Class Codes: H04Q 2213/13149 Change of provider, e.g. network or service
• CPC Class Codes: H04Q 2213/13176 Common channel signaling, CCS7
• CPC Class Codes: H04Q 2213/13513 UPT - personal as opposed to terminal mobility, inc. number portability
• CPC Class Codes: H04Q 2213/13527 protocols - X.25, TCAP etc.
• CPC Class Codes: H04Q 2213/13533 multivendor and hybrid, e.g. public/private, networks, inc. international
• CPC Class Codes: H04Q 2213/13541 routing
• CPC Class Codes: H04Q 2213/13542 numbering plans, e.g. number re-allocation
• CPC Class Codes: H04Q 2213/13547 subscriber, e.g. profile, database, database access
• CPC Class Codes: H04Q 3/0045 involving hybrid, i.e. a mixture of public and private, or multi-vendor systems
• CPC Class Codes: H04Q 3/005 Personal communication services, e.g. provisions for portability of subscriber numbers
• CPC Class Codes: H04Q 3/66 Traffic distributors

Abstract

A method for enabling a plurality of Local Service Providers within a common Numbering Plan Area (NPA) to serve Subscribers of the plurality of Local Service Providers. The method includes the step of assigning to each Subscriber of a Local Service Provider within the common NPA a unique three digit code, hereinafter referred to as a SPA code. The service provider area (SPA) code is used by the telephone system in the same manner presently used for routing calls made when a calling Subscriber dials the NPA code of the called party. Here, however, the SPA code is not dialed by the calling Subscriber. The dialed directory number, NXX-XXXX, of a called Subscriber subscribed to a different Local Service Provider, is sent to a database. The database maintains a record of the relationships between the directory numbers of Subscribers and the SPA codes of the Subscribers. The database retrieves the SPA code associated with the dialed directory number presently serving the called Subscriber. The call is routed as SPA-NXX-XXXX. Because the ten digit format, SPA-NXX-XXXX, is the same as the present NPA-NXX-XXXX, ten digit format, existing signaling and routing mechanisms may be used to route the call. Thus, each one of the Subscribers of each one of the plurality of Local Service Providers is assigned a common SPA code, each one of the Local Service Providers having a different SPA code.

Claims

1. A method for routing a call to a called Subscriber having an assigned directory number, NXX-XXXX or NPA-NXX-XXXX, and having moved to a different location served by a switch having a different exchange code, NYY, and a line code YYYY, comprising the steps of:

(a) dialing the directory number of the called Subscriber;

(b) determining from the dialed number, whether the call is an intra-LATA call or a call to an exchange code (NXX) served by a local switch,

(i) if the call is to an exchange code (NXX) served by the local switch, determining whether the dialed directory number is served by the local switch; and

,

(A) if the dialed directory number is served by the local switch, routing the call to the called Subscriber using the directory number; and

,

(B) if the dialed directory number is not served by the local switch, accessing a database external to the local switch to obtain routing information for the call; and

,

(ii) if the call is an intra-LATA call, determining based on an NPA code of the dialed directory number and the dialed exchange code NXX of the dialed directory number, whether the dialed exchange code supports local number portability, and if it does, then accessing the database external to the local switch to obtain routing information for the call; and

wherein accessing the database external to the local switch comprises the steps of;

(c) adding to the dialed directory number an NPA code if such NPA code is absent from the dialed directory number, to provide a database accessing number;

(d) retrieving from the database, in response to the database accessing number, a corresponding number comprising an SPA code of the called Subscriber'"'"'s service provider plus the NYY exchange code plus the line code YYYY, where

an SPA code is a three digit designation code assigned to each one of a plurality of Local Service Providers within a common Numbering Plan Area (NPA), each one of the Local Service Providers being assigned a different SPA code in the common Numbering Plan Area (NPA); and

(e) routing the call using the corresponding number.

2. The method of claim 1, wherein the directory number, NXX-XXXX, and the NYY exchange code plus the line code YYYY have a same or different Number Plan Area (NPA) code.

3. A method for routing a call to a called subscriber using a dialed number comprising NXX-XXXX or NPA-NXX-XXXX, the method comprising the steps of:

(a) determining from the dialed number, whether;

(1) the dialed number is served by a local switch serving a line from which the call is placed;

or, (2) the call is an intra-LATA call and the dialed number is not served by the local switch; and

,

(i) if the dialed number is served by the local switch, then using the local switch to route the call to the called subscriber using the dialed number;

(ii) if the call is an intra-LATA call and the dialed number is not served by the local switch, determining, based on an NPA code of the dialed number and the exchange code NXX of the dialed number, whether local number portability is available for the dialed number;

(A) if local number portability is available for the dialed number, then accessing an External Local Number Portability Database using the dialed number to retrieve routing information comprising a Service Provider Area (SPA) code, an exchange code NYY and a line code YYYY, and routing the call using the routing information, where

an SPA code is a three digit designation code assigned to each one of a plurality of Local Service Providers within a common Numbering Plan Area (NPA), each one of the Local Service Providers being assigned a different Service Provider Area (SPA) code in the common Numbering Plan Area (NPA); and

,

(B) if local number portability is not available for the dialed number, routing the call using the dialed number.

4. The method of claim 3, wherein prior to accessing the External Local Number Portability Database, if an NPA code is absent from the dialed number, prefixing the dialed number with an NPA code corresponding to the dialed number and using the prefixed dialed number to access the External Local Number Portability Database.

5. The method of claim 3, further comprising using the routing information to provide a number SPA-NYY-YYYY and routing the call using the number SPA-NYY-YYYY.