1. Diameter Signaling Router Mobile Number Portability User Guide
  2. vSTP IDP Relay and MOSMS
  3. MOSMS Overview
  4. Portability Check for Mobile Originated SMS

Portability Check for Mobile Originated SMS

The Portability Check for Mobile Originated SMS (MNP SMS) feature is designed to prevent subscriber use of an incorrect Short Message Service Center by filtering incoming messages based on MAP Operation Code. If the message is a MO Forward Short Message (MOFSM), the Mobile Subscriber Integrated Services Digital Network (MSISDN) number of the originating subscriber, or subscriber phone number, is used to search the MOSMS Mobile Number Portability database.

When a mobile subscriber sends a Mobile Originated Short Message Service message (MOSMS) using a GSM handset, the message is first deposited in a Short Message Service Center (SMSC). The SMSC determines where the intended recipient, who is also a mobile subscriber, is located by querying the Home Location Register (HLR) of the recipient to determine the current Mobile Switching Center (MSC) of the recipient.

The SMSC address to which a message is routed is programmed into the GSM mobile handset. After a subscriber ports to another network, the handset is reprogrammed with the SMSC address for the new network; however, the subscriber could change the SMSC address to the address of the former network, causing Short Message Service (SMS) messages to be sent incorrectly to the former network SMSC of the subscriber. Because the former network would not have billing records for the ported-out subscriber, the subscriber would receive free SMS service.

If a match is found in the MOSMS Mobile Number Portability database to indicate that the subscriber has been ported-out, the vSTP 5 ISS uses the destination SMSC address obtained from the SCCP CdPA to search a list of home network SMSC addresses. If a match is found to indicate that the ported-out subscriber is attempting to send a short message using the SMSC of the subscriber’s former network, the message is discarded. An error message is generated and returned to the originating MSC.

Portability Check for Mobile Originated SMS Call Flow

The MAP_FORWARD_SHORT_MESSAGE (FSM), in the following Call Flow example is used to carry a text message (short message) being transmitted from the mobile handset of one subscriber to the mobile handset of another subscriber. In practice, the short message is delivered first to the Short Message Service Center (SMSC) of the sending subscriber, and then the SMSC is responsible for sending the short message to the intended recipient.

Refer to the following steps in the flow for this call.

The vSTP will perform the following with respect to MNP SMS Feature functionality.

  1. The vSTP receives an UDT message.

  2. vSTP checks whether the service selector value is mosms. If the service selector matches mosms, continue to the next step. If the service selector is not mosms, the message falls through to GTT (#12).

  3. The MAP OpCode is examined. If the OpCode is MO_FSM, PPSMS processing continues with the next step. If the OpCode is not MO_FSM, the message falls through to GTT (#12).

  4. If the PPSMS feature is on, the message falls through to PPSMS processing (#8). If the PPSMS feature is not on, processing continues with the next step.

  5. If the MNP SMS feature is on, the Mobile Subscriber Integrated Services Digital Network (MSISDN) number is used to search the MOSMS Mobile Number Portability subscriber database. If the MNP SMS feature is not on, the message falls through to GTT (#12).

  6. If the MSISDN Number is found in the PDB/DN table, then the portability type of the subscriber is checked for Not Known to be Ported (0) / Ported-out (1) / FNPTFN (2) /Not identified to be ported (36) and processing continues. If the MSISDN Number is not found in the PDB/DN table, the message falls through to GTT (#12). If the portability type is in the range of Prepaid1 (3) to Prepaid32 (35), the message falls through to GTT (#12).

  7. The SCCP CdPA Address is used to search the list of home network SMSC addresses. If a match is found, the ported-out subscriber is fraudulently attempting to send SMS using the SMSC of the old network. The message is discarded; UIM #1129 is issued; an error message is generated and returned to the originating MSC, and the message falls through to #15. If the message is not on the list, the message falls through to GTT (#12).

  8. If the message is from one of the IN Platforms (PPSMS Servers), The message exits from MNP SMS feature functionality and falls through to PPSMS processing (#14). If the message is not from one of the PPSMS Servers, processing continues to the next step.

  9. The MSISDN number (phone number) of the originating subscriber is used to search the MOSMS Mobile Number Portability subscriber database. If the MSISDN Number is found in the PDB/DN table, then continue to the next step. Otherwise, exit from MNP SMS feature functionality and continue with Normal GTT processing (#12).

  10. Check the portability type of the subscriber. If the portability type matches the range of Prepaid1 (3) to Prepaid32 (35), go to #14; otherwise, continue with the next step.

  11. If the subscriber portability type is Not Known to be Ported (0) /Ported-out (1) / FNPTFN (2) /Not identified to be ported (36) and MNP SMS feature is also ON, then go to #7. Otherwise, exit from MNP SMS feature functionality and continue with Normal GTT processing.

  12. Exit from MNP SMS feature functionality and continue with existing processing for other services or GTT.

  13. Exit from MNP SMS feature functionality and continue with existing processing for MOSMS.

  14. Exit from MNP SMS feature functionality and continue with existing processing for PPSMS.

  15. Exit from MNP SMS feature functionality.