A method and system for rating a packet based telephone call determines a source, and optionally a destination location of an Internet Protocol (IP) telephone call based on information contained within a call detail record. The locations are used to rate the call into any of a number of categories including...http://www.google.com.hk/patents/US20040028057?utm_source=gb-gplus-share專利 US20040028057 - Method and system for rating a packet based communication
