USSD EDRs

Introduction

This section describes the Event Data Records generated by the USSD Service Library.

Note that these EDRs are generated directly by the ProcessUssdLuaService and/or UssdNotifyLuaService) service library plugin components, rather than by an n2svcd top-level ‘Application’.

This is because USSD Lua scripting in the n2ttg product uses a relatively direct architecture compared to architecture for Lua scripting of e.g. INAP or SIP.

For USSD, the two applications are:

1. The `SigtranApp` which handles the TCAP/SCCP/SIGTRAN (does not generate EDRs).
2. The `LogicApp` which runs the `ProcessUssdLuaService` service library (generates `USSD` and custom EDRs).

By contrast in the N2ACD-SCP case, there is an intermediate application:

1. The `SigtranApp` which handles the TCAP/SCCP/SIGTRAN (does not generate EDRs).
2. The `LhoScpApp` which implements the SCP INAP state machine (generates `SCP` EDRs).
3. The `LhoScpLuaService` service library within the `LogicApp` (generates custom EDRs).

his is because the SCP state machine is much more complex than the USSD session state machine, and a separate application is necessary. For USSD, the simpler two-application model will suffice.

Note of course that neither ProcessUssdLuaService nor Logic app actually performs the EDR file writing. Instead, these components send an EDR-LOG message to the EdrApp which performs the in-memory buffering, EDR encoding, EDR write-to-disk, file managemement, etc.

The USSD EDR Event Types are:

• USSD-PROCESS
• USSD-PROCESS-E
• USSD-PROCESS-R
• USSD-REQUEST
• USSD-REQUEST-E
• USSD-REQUEST-R
• USSD-END
• USSD-NOTIFY
• USSD-NOTIFY-R
• USSD-NOTIFY-E
• USSD-SHUTDOWN

Common Format

The configuration parameters for configuring EDR output including filename structure and location is defined in the configuration documentation for the EdrApp which is a base component provided by the n2svcd package.

All EDRs are written by the EdrApp application using its file and record formatting rules.

Refer to the n2svcd base documentation for more details on configuring and managing EDR streams, and on the syntax/encoding details for N-Squared EDRs.

USSD-PROCESS EDR

The USSD-PROCESS EDR Event is generated by the ProcessUssdLuaService service library when it first accepts the inbound ProcessUnstructuredSSRequest MAP operation and commences execution of the Lua script.

In order for this (or any other EDR) to be generated, the following service loading steps must succeed.

1. The inbound `TCAP-RECV` must contain a single `Invoke` component with a well-formed `ProcessUnstructuredSSRequest`.
2. The decoded parameters must match a configured `` rule in the service configuration.

If both of these pre-conditions are met, then a USSD-PROCESS EDR will be generated at the start of the script, and at least one other EDR will be generated at (or before) the end of script processing.

Example:

2021-09-30 05:00:54.079<Logic-1632976990-05f220e1>USSD-PROCESS
→ |DREF=333:1:6|LTID=195c5d37|MSISDN=27761485722:1:1|OREF=64221420001:1:1|RPC=2068|RSSN=10|RTID=195c5d36|TEXT=%2A%23101%23

USSD-PROCESS-R EDR

The USSD-PROCESS-R EDR Event is generated by the ProcessUssdLuaService service library when sending the final result back to the handset. This will be present in all cases except when:

• A ReturnError is sent instead, by the decline USSD service library method.
• A TCAP Empty END is sent instead, by the close USSD service library method.
• A TCAP ABORT is sent instead, by an unhandled service logic error.
• A TCAP ABORT or TCAP Empty END is received from the handset/network.

Example:

2021-09-30 21:42:02.997<Logic-1633038118-7274949c>USSD-PROCESS-R
→ |TEXT=NAME ONE/64221420001/333/%2A%23101%23

USSD-PROCESS-E EDR

The USSD-PROCESS-E EDR Event is generated by the ProcessUssdLuaService service library when sending back a final ReturnError component. This happens only when expressly requested by the service logic, using the close USSD service library method.

Example:

2021-09-30 21:42:02.997<Logic-1633038118-7274949c>USSD-PROCESS-R
→ |TEXT=NAME ONE/64221420001/333/%2A%23101%23

USSD-REQUEST EDR

The USSD-REQUEST EDR Event is generated by the ProcessUssdLuaService service library whenever an UnstructuredSSRequest Invoke is sent. This happens when specifically requested by the service logic, using the menu Lua service method.

Example:

2021-09-30 23:14:23.362<Logic-1633043654-4c61bd9a>USSD-REQUEST
→ |TEXT=1. Add-ons%0A2. Packages%0A3. Account Services%0A4. Other Services

USSD-PROCESS-R EDR

The USSD-PROCESS-R EDR Event is generated by the ProcessUssdLuaService service library when any of the following cases occur.

• A ResultResult for the most recently sent UnstructuredSSRequest Invoke is received from the handset.
• The menu timer expires and no result has been received from the handset/network.
• A TCAP ABORT or TCAP Empty END is received from the handset/network.

Example:

2021-09-30 23:14:22.253<Logic-1633043654-4c61bd99>USSD-REQUEST-R
→ |CONTROLLED=1|REASON=Input|TEXT=2

USSD-PROCESS-E EDR

The USSD-PROCESS-R EDR Event is generated by the ProcessUssdLuaService service library when a ReturnError for the most recent sent UnstructuredSSRequest Invoke is received from the handset.

Example:

2021-09-30 23:14:23.361<Logic-1633043654-4c61bd9a>USSD-REQUEST-E
→ |CONTROLLED=1|ERROR_CODE=5

USSD-NOTIFY EDR

The USSD-NOTIFY EDR Event is generated by the ProcessUssdLuaService service library whenever an UnstructuredSSNotify Invoke is sent. This happens when specifically requested by the service logic, using the notify Lua service method.

Alternatively, the USSD-NOTIFY EDR Event is generated by the UssdNotifyLuaService service library whenever an UnstructuredSSNotify Invoke is received. This happens at the start of the service logic when the script is initiated.

Example:

2021-10-01 00:15:19.256<Logic-1633047210-2ab08933>USSD-NOTIFY
→ |TEXT=Top-up Completed Successfully

USSD-NOTIFY-R EDR

The USSD-NOTIFY-R EDR Event is generated by the ProcessUssdLuaService service library when a ResultResult for the most recent sent UnstructuredSSNotify Invoke is received from the handset.

Alternatively, the USSD-NOTIFY-R EDR Event is generated by the UssdNotifyLuaService service library when it sends a ResultResult for an inbound UnstructuredSSNotify Invoke that was received from the handset.

Example:

2021-09-30 23:14:23.361<Logic-1633043654-4c61bd9a>USSD-REQUEST-E
→ |CONTROLLED=1

USSD-NOTIFY-E EDR

The USSD-NOTIFY-E EDR Event is generated by the ProcessUssdLuaService service library when a ReturnError for the most recent sent UnstructuredSSNotify Invoke is received from the handset.

Alternatively, the USSD-NOTIFY-E EDR Event is generated by the UssdNotifyLuaService service library when it sends a ReturnError for an inbound UnstructuredSSNotify Invoke that was received from the handset.

Example:

2021-09-30 23:14:23.361<Logic-1633043654-4c61bd9a>USSD-REQUEST-E
→ |CONTROLLED=1|ERROR_CODE=5

USSD-ABORT EDR

The USSD-ABORT EDR Event indicates that the handset/network abandoned the USSD session by sending or receiving a TCAP ABORT.

Example:

2021-09-30 23:14:23.361<Logic-1633043654-4c61bd9a>USSD-ABORT
→ |DIRECTION=in

USSD-END EDR

The USSD-END EDR Event indicates that the handset/network abandoned the USSD session by sending or receiving TCAP Empty END.

Example:

2021-09-30 23:14:23.361<Logic-1633043654-4c61bd9a>USSD-ABORT
→ |DIRECTION=in

USSD-SHUTDOWN EDR

The USSD-SHUTDOWN EDR Event indicates that the USSD service logic ended with an internal processing error because of:

• Call to the built-in Lua error method directly in the service logic or library function, or
• Internal processing error in the LogicApp framework, or
• Internal processing error in the USSD service library, or
• Invalid message content or sequence detected by the USSD service library.

This EDR is generated independently of any other USSD EDRs associated with the EDR. In most cases, there will be other USSD EDRs associated with this instance containing additional protocol information.

Example:

2021-09-30 23:14:36.360<Logic-1633043654-4c61bda0>USSD-SHUTDOWN
→ |EXCEPTION=Received unsupported ReturnResult operation code 61 on USSD transaction.