1. Virtual Signaling Transfer Point
  2. Overview of vSTP
  3. Stateful Application Feature
  4. Stateful Security Dynamic Learning
  5. Call Flow in Test Mode

2.8.4.2 Call Flow in Test Mode

This mode validates all the learned VLRs at all times. In case the VLR is not validated, it is added to greylist and measurements and alarms are generated. These measurements and alarms allows the operator to validate the whitelists and the overall solution, before they choose to go to the Active mode.

The mode can be changed to ACTIVE mode:
  • Automatically, upon expiry of the test mode time limit, if configured
  • By manual switching of mode
All the messages coming from the VLRs are allowed to the home network. This mode allows the operator to test the VLRs creation in learning mode.

VLR Validation in Test Mode

The following figure shows the vSTP call flow for VLR validation in test mode:

Figure 2-18 VLR Validation in Test Mode


img/vlr-validation-test-mode.png

  1. The incoming message is decoded. An error is generated in case of decode failure.
  2. The message information gets stored in the local database.
  3. Lookup in VLR Whitelist table (Profile).

    If entry is available for new VLR, then skip the validation. Otherwise, continue below steps.

  4. Lookup in DPT:
    • If entry is not available for New VLR, then create the Entry in DPT.
    • If entry in DPT exists, then VLR validation is performed with lookup in UDR for that IMSI.
  5. If record is not found in UDR then send ATI to HLR.
  6. Update success & failure counts based on validation results.
  7. If validation is success then send location update to HLR and send CreateorUpdate event to the UDR for latest timestamp.
  8. If validation is failed then send response based on configured option:

    Fail Action Id is FALLBACK (do not discard messages even if the validation fails in test mode for dynamic VLRs)

  9. The Greylisted dynamic VLRs remain unchanged. They are not moved to Whitelisted or Blacklisted VLRs. However, the event notification for status change (GL->BL, GL->WL, and so on) is raised, based on the threshold values.

Velocity Check in Test Mode

The following figure shows the vSTP call flow for Velocity check in test mode:

Figure 2-19 Velocity Check in Test Mode


img/velocity-check-test-mode.png

  1. 1. The incoming message is decoded.
    1. An Error will be generated in case of decode failure.
    2. A Measurement is pegged for the decode failure with OpCode and CgPA.
  2. The message information is stored in the local database.
  3. If no new VLR entry is available in Dyn VLR Profile table, then create the VLR entry.
  4. Perform validation by sending ReadEvent to UDR for that IMSI record.
    • If the record is available in UDR, then extract the lastUpdatedTimestamp and VLR from UDR response.
    • If the record is not available in UDR, then ATI request is generated towards the HLR identified in the CdPA of the incoming message.

      For a success response from HLR, extract the Age of Location from the ATI Response message and the VMSC address in the HLR.

  5. In case the new VLR from which the SAI/LU was received, matches the old VLR in the UDR/ATI response, no action is performed.
  6. In case the VLR addresses do not match:
    • If old VLR is not available in DPT, then create the entry.
    • If old VLR status is Blacklisted, then entry is not created in DPT. The velocity check results in Validation Failure.