ATI NP Overview

The AnyTime Interrogation Number Portability (ATI NP) feature. An ATI message allows an external server to interrogate an HLR and obtain information about the location and/or state of a GSM subscriber.

Before number portability, SCPs and other querying nodes could easily determine which network the subscriber belonged to based on the digits dialed by the caller. With number portability, subscriber digits cannot be relied upon to determine the subscriber's network.

Anytime Interrogation Number Portability (ATINP) query feature provides a method for querying entities to obtain number portability and routing information for subscribers.

ATINP provides number portability functions for decoding the information in the incoming ATI query message, number conditioning before the Real Time Database (RTDB) lookup, determining the success or failure of the RTDB lookup, and formatting the Return Result or Error Response based on the result of the lookup. ATINP is fully compliant with the ATI standards for Global Number Portability in 3GPP TS 23.066V7.0.0 (2007-06), Support of Mobile Number Portability.

ATINP supports the use of Additional Subscriber Data (ASD) in formatting response messages.

ATINP supports Service Portability functions that allow a subscriber to keep the same phone number when switching from one type of network or service technology to another within the same operator's network. With Service Portability, the subscriber remains with the same operator, but receives service from a different network technology supported by that operator or moves from one physical network to another, with both networks operated by the same service provider. The Service Portability (S-Port)feature allows RTDB GRN Entity digits to be used as Service Portability prefixes for own-network GSM and IS41 subscribers in response digit formats.

ATINP supports functions to cluster CNLs into groups referred to as ROPs, which can be used to simplify routing and simple billing analysis in cases where the number of supported CNLs is very large. The Generic Routing Number field is used to store ROP information.

The ATI NPQ local subsystem in vSTP processes ITU-TCAP ATI messages with the requested information MNP Requested Info parameter. The vSTP responds with an ATIACK message that contains number portability and routing information, or with an ATINACK message if the requested information cannot be provided. The original ATI query is discarded.

ATINP is an EPAP-based feature that requires EPAP provisioning data from the RTDB. Subscriber data is transferred from customer databases to the UDR. The UDR formats the RTDB and loads it to vSTP MP. The RTDB data is used in obtaining number portability information and in determining how to correctly format the ATI ACK response message.

ATI NP performs these actions based on the message received.

• If the incoming ATI query message requested MNP information, ATI NP sends the ATI Ack message to the MSC with the routing number and number portability status information in the MAP portion of the message.
• If the incoming ATI query message requested location information, ATI NP sends the ATI Ack message to the MSC with the location information of the VLR.

An overview of the message handling procedure includes:

1. MSC sends an ATI request to vSTP MP over SS7 links.
   1. vSTP MP decodes and verifies the ATI message.

   2. It checks ATI message to make sure it is a valid request.

      The requestedInfo parameter must be MNPRequestedInfo and/or Location Information.

   3. It decodes the MSISDN parameter from the Subscriber Identity parameter.
   4. It conditions the MSISDN to the international format.
2. vSTP MP queries the UDR NOAM for conditional MSISDN DB.
3. UDR NOAM looks up MSISDN DB and sends a response to the vSTP MP.
4. Determines if the lookup is considered successful based on provisioned options.

   If yes, it uses the entity information to encode ATI ACK response and routes the response to the originator.

   If no, it sends an ATI NACK response with an appropriate error code.

Figure 2-11 Message Flow for ATINP Solution on vSTP