2.2.1 ATI NP Message Handling

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.

This procedure describes how ATI NP handles a message.

1. The ATI query message arrives at vSTP with routing determined by either route-on-gt or route-on-SSN.
   • If the message is route-on-SSN and the SSN number in Called Party Subsystem field in the matches to the ATINP SSN provisioned on vSTP, the message is sent to ATINP subsystem for further processing.
   • If the message is route-on-GT, vSTP decodes the SCCP portion and uses the data to perform ATINP selection based on the CdPA GT fields. The result of this selection provides a service indicator. If the service selector is ATINP, the message is sent to ATINP subsystem for further processing.
2. The message is decoded to verify the opcode and mandatory parameters.
   • If the MAP message opcode is ATI, the MSISDN and requested information parameters are decoded.
   • If MSISDN is valid and either MNPinfo or LocationInfo or both parameters are present, further number conditioning is performed.
   • Otherwise, an error message is sent back to originator.
3. The decoded DN is conditioned to an international number before performing a UDR NPDB lookup.
   The DN is considered to be in international format if either of the following conditions are true.

   • VstpMnpOptions:ATISNAI = INTL

     OR

   • VstpMnpOptions:ATISNAI = NAI and NAI field from MSISDN is INTL (0x1) or Network Specific Number (0x3).

   If the incoming DN is in national format, VstpMnpOptions:DefCC is prepended to the DN to condition it to international format.

4. The UDR NPDB database lookup involves two steps:

   1. First the exception or individual number database is searched for a match.

      If the match is found, then the data associated with this entry is considered.

   2. If the conditioned number is absent in the exception (individual) database, then the number range database is searched.

      If the match is found then the data associated with this range entry is considered. If the search is unsuccessful then the result is no match.

5. UDR NPDB lookup is considered successful if:

   • VstpMnpOptions:ATINPTYPE = ANY and MSISDN is found in the NPDB with entity type = RN, SP, or GRN.

     OR

   • VstpMnpOptions:ATINPTYPE = ALWAYS and MSISDN is not found in individual or range entries.
6. If the UDR NPDB lookup is successful and if the ATI query contains the MNP request information parameter, ATINP sends the ATI ACK response message with these fields in the message:
   • Routing Number: Formatting is determined by VstpMnpOptions:ATIACKRN option
   • IMSI: Formatting is determined by VstpMnpOptions:ATIACKIMSI option
   • MSISDN: Formatting is determined by VstpMnpOptions:ATIACKMSISDN option
   • Number Portability Status:
     • Not Known To Be Ported (0)
     • Own Number Ported Out (1)
     • Foreign Number Ported To Foreign Network (2)
     • Own Number Not Ported Out (4)
     • Foreign Number Ported In (5)
7. If UDR NPDB lookup is successful and if the ATI query contains the Location Information request information parameter, ATINP sends the ATI ACK response message with these fields in the message:
   VLR Number: Formatting is determined by VstpMnpOptions:ATIACKVLRNUM option
8. If UDR NPDB lookup is unsuccessful, ATINP sends the ATI NACK response message with the error code = “UnknownSubscriber”.

Figure 2-12 ATI NP Function Flow Chart - Sheet 1 of 3

Figure 2-13 ATI NP Function Flow Chart - Sheet 2 of 3

Figure 2-14 ATI NP Function Flow Chart - Sheet 2 of 3