Patent ID: 7139263

Claim:
A method of establishing call setup in relation to a call between calling and called parties over a Voice over Internet Protocol (VoIP) network, the VoIP network comprising a signaling gateway, a first access switch directly connecting the calling party to the VoIP network, and a second access switch connecting the called party to the VoIP network through the Public Switched Telephone Network (PSTN) and associated Signaling System Seven (SS7) network, the method comprising the steps of: terminating the call in the first access switch; issuing a first Signaling Initiation Protocol (SIP) INVITE message from the first access switch to the second access switch, and maintaining session state associated with the call in at least one of the first and second access switches, wherein the session state includes information related to a nature of a call and information related to control of an activity of a component in a VoIP network; after receiving the first INVITE message, sending a second INVITE message from the second access switch to the signaling gateway; and maintaining transaction state associated with the call setup in the signaling gateway during only the pendency of the call setup transaction, wherein the transaction state includes information related to call set up, call tear down, and a feature invocation.