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.

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