In a Cisco Contact Center Enterprise (CCE) Call Flow, the IVR leg is established when the Cisco Voice Portal (CVP) establishes an HTTP link with the VVB (Virtualized Voice Browser) or an IOS VXML Gateway. This connection is crucial for delivering and executing VXML scripts, which define the IVR's logic and caller interactions. The IVR leg's establishment is a key step in the call flow, enabling the system to provide self-service options, collect caller information, and route calls based on dynamic conditions.References:Cisco CCE and CVP documentation provides insights into call flow processes, specifically detailing the role of the VVB and the establishment of the IVR leg.