Patent ID: 8843638

Claim:
A method performed in a radio access network, the method comprising: establishing a session between an access terminal and a first radio network controller through a first radio node, the first radio node being controllable primarily by the first radio network controller, maintaining the session with the first radio network controller as the access terminal moves from a coverage area of the first radio node toward a coverage area of a second radio node, the second radio node being controllable primarily by a second radio network controller and controllable subordinately by the first radio network controller, establishing a route for the session established with the first radio network controller through the second radio node, and responsive to determining that an active set of the access terminal contains only radio nodes which are subordinately controlled by the first radio network controller, initiating an active handoff from the first radio network controller of a first subnet to the second radio network controller of a second subnet including transferring the session from the first radio network controller to the second radio network controller without dropping an active call associated with the session, wherein the first and second radio network controllers are located in different subnets of the radio access network.