Answer to L.T.T. – 12

The answer to LTT-12 was B = Grey routing / Sim boxing. Revenue leakage occurs when inbound calls do not transit through the gateway (interconnect) switch, resulting in lost termination revenues. Instead, the call is routed to a local SIM box gateway (usually over the internet) and the call appears to originate as an on-net call.

The following action plan is recommended to eradicate bypass activity:-

  • Ring fence 1 or 2 resources to permanently monitor and close down bypass for the next few months.
  • Undertake a sustained calling campaign to identify the source of the bypass.
  • Automate the disconnection process to reduce the time from detection to disconnection to under 30 minutes.
  • Utilize daily reports from the FMS or data warehouse to identify signatures / profiles of suspected MSISDNs based on characteristic usage patterns.
  • Define a disconnection process with cross functional agreement with legal, regulatory, marketing etc based on usage patterns e.g. high outbound usage but with no inbound calls, zero SMS, zero WAP contexts, etc, and with all calls originating within a limited number of cell sites.
  • Co-ordinate with local police enforcement officers to arrest fraudsters committing bypass, and confiscate their equipment. Also identify the common point of SIM card sale and monitor dealers suspected of collusion.
  • Cross industry collaboration with local operators to close down International bypass traffic transiting via national interconnect routes.
  • Align interconnection and retail pricing strategy to minimize opportunities for bypass.

The correct answer came from Michael Lazarou, with the following action plan:

The actions I’d take would be to run some test calls – get the CDRs (both retail and interconnect) and check the details – basically if the CLI matches the A_Number. In addition, we can check the latest subscriptions of the 1000 free onnet minutes promo – whether there was anyone that bought a large amount together or used strange customers details or many lines to one subscriber…

The next LTT will be published on 12 January.

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.