System and method for providing value-added services (vas) in an integrated telecommunications network using session initiation protocol (sip)

A system and method for providing Value-Added Services (VAS) in an integrated telecommunications network (200) having a packet-switched network portion (PSN) operable with Session Initiation Protocol (SIP). The integrated telecommunications network includes a SIPextSSP server (204), a trigger server (206), and a service node (212)having a Service Logic Program (SLP)(216) that is operable with Intelligent Network Application Protocol (INAP). The SIPext SSP and service nodes are provided with the capability to communicate using SIP-compliant messaging. New header fields are provided that specify operations to be performed by the service node (212) with respect to a service. INAP service parametric data is also provided in the header fields in a sequential form. When a call is received in the SIPext SSP server (204) for a user having a subscription for a VAS, it queries the user profile stored in the trigger server (206). If the user is subscribed for a service, a SIP request message is formulated based on the user profile, wherein appropriate headers are populated with relevant parametric information and call context data. The service node (212) launches the SLP (216) based on the information provided in the request message and sends a SIP response message to the SIPext SSP (204) server with an instruction concerning the provisioning of the VAS. The SIPext SSP server, thereafter, takes an appropriate action based on the response message and any parametric information contained therein.