Figure 5 depicts the successful MO–SM scenario, utilizing the GSM method. The IS–41 method for the MO-SM scenario is depicted in Figure 6.

Figure 5. MO—SM Scenario (GSM)

1. The MS is powered on and registered with the network.
2. The MS transfers the SM to the MSC.
3. The MSC interrogates the VLR to verify that the message transfer does not violate the supplementary services invoked or the restrictions imposed.
4. The MSC sends the short message to the SMSC using the forwardShortMessage operation.
5. The SMSC delivers the short message to the SME (and optionally receives acknowledgment).
6. The SMSC acknowledges to the MSC the successful outcome of the forwardShortMessage operation.
7. The MSC returns to the MS the outcome of the MO-SM operation.

Figure 6. MO—SM Scenario (IS—41)

1. The MS transfers the SM to the MSC.
2. The MSC interrogates the home SMSC to verify that the message transfer does not violate the supplementary services invoked or the restrictions imposed. The MSC sends the short message to the home SMSC using the SMSPP Invoke operation.
3. The SMSC delivers an acknowledgment to the MSC.
4. The MSC returns order release to the MS.
5. The SMSC queries the HLR for the location of the destination MS.
6. The HLR returns the destination (MSC) serving the destination MS.
7. The SMSC delivers SM to the MSC serving the destination MS.
8. The SMSC delivers the short message to the MS.
9. The MS acknowledges to the MSC the successful outcome of the SMSDPP operation.
10. The MSC returns to the SMSC the outcome of the MO–SM operation (delivery successful).