Archive for the Quizzes Category

This months LTT by Arun Rishi Kapoor was won by Abhijeet Singh from Subex for providing the first correct answer.



Congratulations to all those who took part in this months quiz. The next LTT will be published on Monday 16th December.

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Welcome to this month’s LTT by Arun Rishi Kapoor.

Crossword Challenge

LTT11 - 1


1 Call me if you have enough money for fun and games (3)
2 An insider’s con (8,5)
3 Micro is bigger brother of mini and nano (3)
4 Default passwords may brings this to you (3,7)
5 High speed data (3)
6 If two operators A and B are not ________ partners then it would not be possible for a customer of Operator A to communicate with a customer of Operator B (12)
7 Committed to fighting mobile Industry crime (4)
8 Use me to bypass phone company and its charges (4)
9 Technologies that have reduced the amount of power and time necessary for information to be communicated (3)
10 Control & supervises the Base Transceiver Stations (3)
11 Transfer of identity. Recall Mi2 (7)


8 Roaming network (4)
9 Part of IMSI to identiy the country (3)
12 A database of all subscribers (3)
13 Internet Protocol (2)
14 Causes interconnect termination revenue loss (6)
15 A tool to detect & prevent crime (3)
16 Optic fiber technology  of a broadband network architecture (4)
17 Largest mobile telephony in US (4)
18 Aim to optimize a service providers operational and process infrastructure (3)
19 Geographic position (4,4)
20 Local loop on which origination and termination of call happens (4)
21 Fraud occurs mainly where credit checking procedures are tightly controlled and fraudster uses another persons ID (5)
22 Happens when services are delivered but not billed (7)


5 Police services for Telecommunications (3)
10 Creditor’s loss (3,4)
23 Consists of fiber optic, telephone, cellular networks and comms satellites. Even consists of undersea cables interconnected by switching centers (4)
24 A third generation mobile cellular system developed by 3GPP (4)


25 Expert opinions for communication providers (4,2)
26 An act to steal (5)

Please send your completed answers in this file to

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This month’s LTT by Arun Rishi Kapoor was meant to illustrate that operational performance can be enhanced by fine tuning the alarm rules, to eliminate unnecessary false alarms. This would then allow the RA-FM team to also concentrate on alarms coming from the new roll out of 4G/LTE and Mobile Money services, without the need to recruit more staff.  

The CFO wanted to know the following:

Which network was contributing to the most number of false alarms?

You need to create a pivot on the (LTT_10_Alarms.xls) file to find the maximum number of false alarms.

LTT10 pic1

The correct answer is Network F.

What configuration entities can be fine tuned in the Industry Alert Violation rule to lower the number of false alarms in the FMS?

Based on the statistics of the pivot on the (LTT_10_Alarms.xls), the following recommendations can be given.

  1. As most of the false alarms are coming from Networks A, B, D, E & F, it would be better to create a separate rule for these Networks. In the extreme case, we could consider turning the alarms off for some of these Networks altogether but this is not advisable for extended periods of time.
  2. Since all of the fraud is being generated in Network C, but is also contributing to some false alarms (41), the Fraud Manager could expand the rule from the first 7 digits (cc+4 digits) to 9 digits (cc+6 digits) to make the rule more accurate.
  3. Out of the 1780 countries in the industry alert dump file, fraud alarms are only found in 15 countries (see table below).

 LTT10 pic2

Thus the three configuration entries – network, country and called number prefix is causing lots of false alarms and requires fine tuning.

How many calls were made to numbers in the Industry Alert Dump File?

  1. In the (LTT_10_xDRs.xls) file, take the NEW CALLED NUMBER field - 7 digits (cc+4 digits) and then copy them into a new column named [CALLED NO (first 7 digits)].
  2. Now do a vlookup of this new column to the column – [Range (cc + 4 digits)] in the (LTT_10_Industry_Alert_Dump.xls) file.
  3. For the B number ranges matching, these are the calls made to the Industry Alert dump.

The correct answer is 2410 calls and can be found in this file.

Congratulations to three times winner, Michael Lazarou, and Deepak Chand for providing the correct answer. The next LTT will be published on Monday 18th November.

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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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This month’s LTT by Guy Howie was meant to illustrate the importance of assuring destination dial codes, their descriptions, and the associated rating charges and internal rating system logic.  The trick is to be able to validate and spot errors in the detail, even though the margins can look good.

Identifying what went wrong in Call Rating – How well did you do ?

  • In the first example, the charging mechanism was being applied incorrectly – customers were being overbilled because the duration element of the charge was being applied immediately instead of after the first 60 seconds as advertised. This type of error can easily arise from misunderstandings between IT and the Business.
  • In the second example, the rate applied was 1 pence per minute instead of 10 pence per minute – a simple error, perhaps caused when keying in a rate and getting the decimal point in the wrong place.
  • The third and fourth examples were rating correctly, with the fourth example illustrating that negative margin calls can be a natural consequence of ‘free/ bundles minutes’ type packages, and the values of these should be monitored.
  • The fifth example shows how the losses can grow when there is an error in the dial codes, for example when the minutes are to a more expensive Poland International Mobile destination but the dial code has not been setup in rating.
  • In the sixth example, we see a common situation where the calls to new country, in this case to Sint Maartin, are rating as USA calls because the Sint Maartin Dial code was not set up in rating. The USA often has a default code in call rating like “001” – this means all 001 terminating traffic not set up correctly will rate as USA traffic!

Finally, we see a current area of pain for operators in the last example – where some destinations are being classed by International Carriers as ‘Mobile’ or ‘Special’ because of issues like numbering abuse and International Revenue Share. In the world of retail, the calls are often referred to as fixed line and so losses can arise.

The above examples are all real life examples which we at BIAAS have seen more than once. Congrats to Arun Kapoor and Michael Lazarou for providing by far the closest and most comprehensive answers.

The next LTT will be published on Monday 21st October.


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