Lunch Time Teaser – 08

Welcome to this month’s LTT by Lionel Griache.

The Challenge

You are the Revenue Assurance manager of a GSM telecom operator. The CTO is coming to your office, intrigued by an unusual graph on his Revenue Assurance dashboard (below). He’s seeing a strong deviation between the SMSc and the postpaid billing system, for SMS generated by postpaid subscribers. The deviation takes place during almost a 24 hour period.



After a quick call to the manager of the postpaid billing system, you learn that there was also an increase of exceptions in the processing of this revenue-stream. The increase in exceptions is due to a large number of SMS that can’t be associated to any known active postpaid subscriber (unknown or disconnected A-number). The CTO is asking for a possible explanation to this unusual deviation.

Looking at the proposed answers below, which one is most likely to be the explanation?

  1. Because of a crash & recovery of the mediation application, the Revenue-Assurance system received duplicate CDRs, artificially reporting higher number of SMS on the SMSc graph.
  2. This is a classical revenue leak. The billing system didn’t receive all the files produced by the SMSc during the period. Collecting the files and processing them in Billing will allow to recover the revenue.
  3. This is a possible case of fraud. The fraudsters are generating SMS using the postpaid number-range as the originating number.
  4. The team managing the billing system probably forgot to configure the new short-code that the marketing team launched at the start of the week
  5. The extra number of SMS is simply due to the final of the Basket Ball World Championship taking place in the country this week. Roaming visitors are generating a high number of SMS and their A-number was simply not recognized by the postpaid billing system.
  6. The SMSc had technical issues during the period and it took an average of 3 attempts for the SMSc to deliver each SMS, generating a much higher graph on the SMSc than on the billing system.

To receive the answer, please send an email to with LTT-08 in the heading.

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