INPQ Overview

The Intelligent Network Application Part (INAP) Number Portability Query (INPQ) feature supports number portability in the network,, which allows subscribers to switch their telephone service provider while retaining their original telephone number.

INPQ performs these actions based on the message received.

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

An overview of the message handling procedure includes:

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

   2. It checks INPQ 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 INPQ ACK response and routes the response to the originator.

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

Figure 2-15 Message Flow for INPQ Solution on vSTP