1. Diameter Signaling Router Mobile Number Portability User Guide
  2. vSTP IDP Relay and MOSMS
  3. MOSMS Overview
  4. Prepaid Short Message Service Intercept
  5. Prepaid Short Message Service Intercept Call Flows

Prepaid Short Message Service Intercept Call Flows

The MAP_FORWARD_SHORT_MESSAGE (FSM), in the following Call Flow examples 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.

Successful Delivery of Mobile Originated FSM from Contract/Postpaid Subscriber

The following figure describes the steps in the flow for this call:

Figure 5-11 Successful Delivery of MO_FSM from Contract Subscriber

img/c_prepaid_sms_intercept_call_flows-fig1.jpg
  1. The Gateway Mobile Switching Center (GMSC) sends the Mobile Originated Forward Short Message (MO_FSM) to the vSTP with PPSMS (TCBEGIN).

    Based on MTPDPC = vSTP point code and SCCP CdPA TT, NP, NAI, SSN, and GTI, the message is pre-selected for PPSMS service. If service is not PPSMS, the message falls through to GTT.)

    Next, the MAP OpCode and SCCP CgPA GTA are examined. The OpCode is MO_FSM and the CgPAGTA is not from one of the IN platforms, therefore, PPSMS processing continues. (If the OpCode is not MO_FSM, or if CgPA GTA is for one of the IN platforms, the message falls through to GTT.)

    The vSTP queries the DB using the sender's MSISDN from the OA field in the MAP portion of message.

    MSISDN is present in the database, but the portability type is not in the range of prepaid1 to prepaid32, meaning the sender is not a prepaid subscriber.

  2. The vSTP therefore GTT-routes the MO_FSM to the SMSC (TCBEGIN).
  3. The SMSC returns the MO_FSM_ack (TCEND).
  4. One of two possibilities:
    1. The SMSC sends the MO_FSM_ack route-on-SSN to the GMSC, then the SRF will simply MTP route the MO_FSM_ack to the GMSC. G-Port is not involved.
    2. The SMSC sends the MO_FSM_ack route-on-GT, and the service selectors indicate G-Port/PPSMS. CdPA SSN = GMSC, which is same as SMSC, so PPSMS is selected. As PPSMS decodes message, it discovers it is a TCEND. Therefore, the message falls through to normal GTT and is routed to the GMSC.

Successful Delivery of Mobile Originated FSM from Prepaid Subscriber

The following figure describes the steps in the flow for this call:

Figure 5-12 Successful Delivery of Mobile Originated FSM from Prepaid Subscriber

img/c_prepaid_sms_intercept_call_flows-fig2.jpg
  1. The Gateway Mobile Switching Center (GMSC) sends the Mobile Originated Forward Short Message (MO_FSM) to the vSTP with PPSMS (TCBEGIN).

    Based on MTPDPC = vSTP point code and SCCP CdPA TT, NP, NAI, SSN, and GTI, the message is pre-selected for PPSMS service. If service is not PPSMS, the message falls through to GTT.

    Next, the MAP OpCode and SCCP CgPA GTA are examined. The OpCode is MO_FSM and the CgPAGTA is not from one of the IN platforms, therefore, PPSMS processing continues. If OpCode is not MO_FSM, or if CgPA GTA is for one of the IN platforms, the message falls through to GTT.

    The vSTP queries the DB using sender's MSISDN from SM RP OA field in MAP portion of message.

    MSISDN is present in the database, and the portability type is prepaid1, meaning the sender is a prepaid subscriber.

  2. The vSTP forwards the MO_FSM to the IN Platform (TCBEGIN) associated with prepaid1, after checking mated application or mated relay node table.

    The portability types prepaid1 through prepaid32 are used to select which of the IN platforms the message should be sent.

  3. The IN Platform checks the account, finds there is enough credit to send the message, opens a new TCAP dialogue, and returns the MO_FSM to the SRF (TCBEGIN-2).
  4. The message arrives at vSTP and is again selected for PPSMS service based on CdPATT, NP, NAI, GTI, and CdPA SSN = SMSC. The OpCode is MO_FSM but the SCCP CgPA GTA is IN platform, therefore, PPSMS service is not indicated and the message falls through to GTT and is routed to the SMSC.
  5. The SMSC returns the MO_FSM_ack to the IN platform (TCEND-2). There are two possibilities:
    1. The SMSC sends the MO_FSM_ack route-on-SSN to the IN platform, then the SRF will simply MTP route the MO_FSM_ack to the IN platform. G-Port is not involved.
    2. The SMSC sends the MO_FSM_ack route-on-GT, and the service selectors indicate G-Port/PPSMS. CdPA SSN = GMSC, which is same as SMSC, so PPSMS is selected. As PPSMS decodes the message, it discovers it is a TCEND. Therefore, the message falls through to normal GTT and is routed to the GMSC.
  6. The IN Platform transfers the MO_FSM_ack to the first transaction and returns the MO_FSM_ack to the SRF (TCEND).
  7. One of two possibilities:
    1. The IN platform sends the MO_FSM_ack route-on-SSN to the GMSC, then the SRF will simply MTP route the MO_FSM_ack to the GMSC. G-Port is not involved.
    2. The IN platform sends the MO_FSM_ack route-on-GT, and the service selectors indicate G-Port/PPSMS. CdPA SSN = GMSC, which is same as SMSC, so PPSMS is selected. PPSMS decodes message, discovers it is a TCEND, and the message falls through to normal GTT and is routed to the GMSC.

Unsuccessful Delivery of Mobile Originated FSM from Prepaid Subscriber - Credit Check Failure

The following figure describes the steps in the flow for this call:

Figure 5-13 Unsuccessful Delivery of Mobile Originated FSM from Prepaid Subscriber at SCP

img/c_prepaid_sms_intercept_call_flows-fig3.jpg
  1. The Gateway Mobile Switching Center (GMSC) sends the Mobile Originated Forward Short Message (MO_FSM) to the vSTP with PPSMS (TCBEGIN).

    Based on MTPDPC = vSTP point code and SCCP CdPA TT, NP, NAI, and GTI, the message is pre-selected for PPSMS service. If service is not PPSMS, the message falls through to GTT.

    Next, the MAP OpCode and SCCP CgPA GTA are examined. The OpCode is MO_FSM and the CgPAGTA is not from one of the IN platforms, therefore, PPSMS processing continues. If the OpCode is not MO_FSM, or if CgPA GTA is for one of the IN platforms, the message falls through to GTT.

    The vSTP queries the DB using sender's MSISDN from the SM RP OA field in the MAP portion of message.

    MSISDN is present in the database, and the portability type is prepaid1, meaning the sender is a prepaid subscriber.

  2. The vSTP forwards the MO_FSM to the IN Platform (TCBEGIN) associated with prepaid1.

    The portability types prepaid1 through prepaid32 are used to select to which of the IN platforms the message should be sent.

  3. The IN Platform checks the account, finds there is not enough credit to send the message, and rejects the message by returning a MO_FSM_Neg_Response to the SRF (TCEND).
  4. One of two possibilities:
    1. The IN platform sends the MO_FSM_Neg_Response route-on-SSN, then the SRF will simply MTP route the MO_FSM_Neg_Response to the GMSC. G-Port is not involved.
    2. The IN platform sends the MO_FSM_Neg_Response route-on-GT, and the service selectors indicate G-Port/PPSMS. CdPA SSN = GMSC, which is same as SMSC, so PPSMS service is selected. PPSMS decodes message, discovers it is a TCEND, and the message falls through to normal GTT and is routed to the GMSC.