DCA Not Terminating All Diameter Multiple-Service-Credit-Cotrol(MSCC) Rating-Groups Correctly (Doc ID 1506050.1)

Last updated on OCTOBER 18, 2016

Applies to:

Oracle Communications Network Charging and Control - Version 5.0.0 and later
Information in this document applies to any platform.

Symptoms

The behaviour of the Diameter Control Agent (DCA) changed in NCC 5.0.0.0 with not all Rating-Groups (RG) provided in a final terminating DIAMETER Credit-Control-Request (CCR-T) being responded to and closed.  This occurred for Multiple-Services-Credit-Control (MSCC) data sessions that had more than one RG and in which, at least one RG, had a transient failure error Result-Code (40xx).  DCA's Credit-Control-Answer Terminate (CCA-T) response only returned the failed MSCC-RG with a permanent failure Result-Code (50xx).  This left any other RG(s) in a hung state on the GGSN (cannot try again due to permanent failure), Service Logic Controller (SLC) and Voucher Wallet Server (VWS).

Consider as an example the following MSCC Credit-Control data session that uses two rating groups:

In the simple scenario, RG 250 is the normal (or default) and RG 240 is a free rating group (to allow redirection to a top-up server).  However RG 250 has no funds and DCA returns a transient failure result back to the GGSN, which then requests RG 240 so the subscriber may credit their account again.  Here is a sequence diagram showing the basic message flow:

    GGSN                             DCA
  1. |         CCR-Initial            |
     |------------------------------->|
     |         CCA-I (2001)           | DIAMETER_SUCCESS
     |<-------------------------------|
     |                                |
  2. |       CCR-Update (RG-250)      | * default data rating group - no credit
     |------------------------------->|
     |         CCA-U (4012)           | RG-250 (DIAMETER_CREDIT_LIMIT_REACHED)
     |<-------------------------------|
     |                                |
  3. |         CCR-U (RG-240)         | * self-care rating group (topup server) - free
     |------------------------------->|
     |         CCA-U (2001)           | RG-240 DIAMETER_SUCCESS
     |<-------------------------------|
     |                                |
  4. |         CCR-U (RG-240)         | * self-care rating group
     |------------------------------->|
     |         CCA-U (2001)           | RG-240 DIAMETER_SUCCESS
     |<-------------------------------|
     |                                |
  5. |   CCR-Terminate (RGs-250/240)  |
     |------------------------------->|
     |         CCA-T (5008)           | MSCC: - RG-250 (DIAMETER_AVP_NOT_ALLOWED, Failed-AVP Used-Service-Unit)
     |<-------------------------------|       - RG-240 (not provided)
 End |                                |
    GGSN                             DCA

In this example, DCA's final MSCC Credit-Control-Answer Terminate contains a permanent error result code for RG 250 and RG 240 is not responded to at all.

To confirm these symptoms take a network trace of the DIAMETER messaging that will show the incorrect final answer from DCA looking similar to this:

INCORRECT BEHAVIOR

Changes

 Installation, or upgrade, of NCC 5.0.0.0 (Intrepid) release.

Cause

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