Lunch Time Teaser – 10

This month’s LTT comes from Arun Rishi Kapoor, who is a Consultant at Subex with 6+ years experience in Telecom Fraud Management Operations & Consulting. As a Fraud Consultant, he is responsible for supervising & establishing best practices in Telecom Frauds, data analytics, requirement gathering & business scoping activities.  Arun has worked with more than 15 telecom Operators across the globe along with onsite assignments in APAC and MENA region. Arun graduated from Jaypee University of Information Technology (Himachal Pradesh, India) with a Bachelor of Technology in Computer Science Engineering.

The challenge

You work for a Telco which is about to launch 4G LTE & mobile money services. The CFO has asked you to check the feasibility of decreasing the existing alarm count but not at the cost of fraudsters bypassing the evaluation rules. This is required to let the Fraud team work on new alarms coming from 4G LTE and mobile money, thus saving to recruit new employees. The CFO asks you to report back to him after lunch.

You glance at the monthly alarm statistics and find the rule “Industry Alert Violation” contributes to 75% of the false alarms.

You have the following information available to help you:

1. The alarm information over the last month detailing the status of each case.

2. The call details of the subscribers who may violate the rule “Industry Alert Violation”.

3. The “Industry Alert Violation” rule generates an alarm in the FMS if the caller makes any call with the following paramters:

  • Called party number (called_number) having  prefix matching with the “Range (cc + 4 digits)” column of the Industry Alert Dump file
  • If the call is outbound
  • If the call is voice
  • If the network of the caller belongs to A, B, C, D, E or F
  • If the call duration is > 2 seconds
  • If the call is cross border.

4. The Industry Alert Dump file is simlar to that of the GSMA’s FF hot B-number database. It contains a list of all reported B-numbers used in fraudulent activities. 

The CFO would like to know the following.

  • Which network is contributing to the most number of false alarms?
  • What configuration entities can be fine tuned in the Industry Alert Violation rule to lower the number of false alarms in the FMS?
  • How many calls were made to numbers in the Industry Alert Dump File?

Please email your answers to

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2 Comments on "Lunch Time Teaser – 10"

  1. Man, this is a hard one.

  2. Dear Rachel,

    A look up (vlookup) function in excel may easy the quiz. We would be happy you trying it again and submit your response.

    Thank you

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