摘要：National Telecommunication Regulator in many countries around the world imposes call termination taxes on national calls as well as international calls landing in that country. In many third world countries, every year up to 90 % of the international traffic bypasses regulatory checks, causing a huge revenue loss to the country. The use of illegal gateways to bypass the Voice Clearing Houses to terminate international traffic using VoIP gateways, GSM / local line branch exchanges or other related equipment are the simplest means of Grey traffic. Use of the encryption and other network design techniques are the easiest methods to hide the VoIP traffic from any clearing house. We have proposed an architecture based on a mathematical model to detect, segregate and qualify VoIP traffic (Grey) into different categories. The proposed model identifies grey traffic, through traffic analysis techniques coupled with statistical anomaly based intrusion detection system and behavior analysis.
关键词：voice over internet protocol (VoIP); grey traffic; international clearing house (ICH); intrusion detection system (IDS); statistical analysis
