Whats the technique CDrtools using to tackle this problem?

Thanks

Jim

http://cdrtool.ag-projects.com/EVALUATION.txt

CDRTool evaluation software is a stripped down version of CDRTool. The following features are missing from this version:

- Rating and prepaid engine - SOAP/XML provisioning interface - Anti-fraud quota based mechanism for SIP Express Router - Accounting for SIP Express Router for calls with no BYE messages - ASR statistics and grouping per Q931 release code or SIP status - Group calls per Carrier, Billing Party or Source IP