It involves illegally obtaining profits by taking advantage of the way international telephone calls are billed and revenue is shared. 

• Fraudulent Call Generation: IRSF typically involves generating a large volume of calls to premium-rate international numbers. Fraudsters often collaborate with or operate these premium-rate services, thereby profiting from the call charges.

• Exploiting Revenue Sharing Agreements: The fraud capitalizes on the agreements between telecom operators that share revenue from international calls. The fraudsters' share of this revenue comes from the high charges of the premium-rate numbers.

• Use of Stolen or Cloned SIM Cards: IRSF often involves using stolen or cloned SIM cards to make the fraudulent calls, thereby avoiding direct payment for these calls.

• Wangiri Scam: A common method used in IRSF is the "wangiri" or "one ring and cut" scam, where calls from premium-rate numbers ring once and hang up, prompting the victim to call back and be charged high rates.

International Revenue Share Fraud represents a significant challenge in the telecommunications industry, requiring ongoing vigilance and advanced detection methods to protect against financial losses and maintain the integrity of international calling services.