To provide a service customized for each user and for each application, when user host terminal H1 communicates with user host terminal H2 using VoIP, the terminal H1 transmits a service initiation message to service execution units SN1 and SN2. By this message, the service execution unit SN1 and SN2...http://www.google.ca/patents/US7424538?utm_source=gb-gplus-sharePatent US7424538 - Service control network system
