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Answer to L.T.T. – 03

This month's correct answers came from three times winner Lionel Griache at ProactiveRA, and Srinivas Chikkala from India.To solve LTT-03 some basic CDR reconciliation matching between MSC1 & MCS2, to the interconnect I/C Gateway was required. The results would show there are some CDRs present at the interconnect I/C Gateway, but are not present on MSC1 or MSC2. The missing CDRs correspond to off-net calls with a short duration of under 5 seconds.Browsing through the CDR data of both MSC1 & MSC2 shows there are no calls under 5 seconds of duration, which indicates the problem could also include on-net calls as well. Although it is not possible to determine if the calls originated from either MSC1 or MSC2, the lack of calls under 5 seconds in them both points to the problem being in the two switches. Therefore, the most likely cause of the revenue leakage will have to be answer C - MSC1 & MSC2.The next LTT will be published on Monday 15th April.

This month’s correct answers came from three times winner Lionel Griache at ProactiveRA, and Srinivas Chikkala from India.

To solve LTT-03 some basic CDR reconciliation matching between MSC1 & MCS2, to the interconnect I/C Gateway was required. The results would show there are some CDRs present at the interconnect I/C Gateway, but are not present on MSC1 or MSC2. The missing CDRs correspond to off-net calls with a short duration of under 5 seconds.

Browsing through the CDR data of both MSC1 & MSC2 shows there are no calls under 5 seconds of duration, which indicates the problem could also include on-net calls as well. Although it is not possible to determine if the calls originated from either MSC1 or MSC2, the lack of calls under 5 seconds in them both points to the problem being in the two switches. Therefore, the most likely cause of the revenue leakage will have to be answer C – MSC1 & MSC2.

The next LTT will be published on Monday 15th April.

Lee Scargall
Lee Scargall

Lee is a senior risk management professional. He has extensive experience of managing both ERM and RAFM teams in telcos around the world, having worked for Ooredoo Group, Cable & Wireless and T‑Mobile UK.

Lee is a regular presenter of The Communications Risk Show, our livestreaming discussion program.

Lee earned a PhD in Electrical and Electronic Engineering from the University of Newcastle upon Tyne, UK, for advanced research in to 3G video-telephony.

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