| Previous slide | Next slide | Back to the first slide | View Graphic Version |
Connected handover.
Backward handover is initiated by the mobile and controlled using the connection to the currently active base-station.
Shown are the mobile two base-stations and the fixed switching points. The mobile and base have meta-signalling processes indicated.
The mobile uses the handover signalling channel to signal to the base and FSP that a handover is required to the new base station.
The FSP creates a copy of the currently active virtual path and virtual circuits to the new base-station. The virtual circuits via the original base-station remain active whilst this ocurrs. The operation of virtual path copying is a relatively slow process, using standard ATM signalling protocols, typically taking 10s to 100sof milliseconds. Once the path is complete the FSP acknowledges to the base station which acknowledges the mobile.
The mobile now switches physical layer and initiates the meta-signalling protocol to connect to the new base-station.
The meta-signaling protocol establishes the ATM signaling, and handover-signaling channels to the new base-station by allocating a new VPI for the mobile.
During the path creation process the mobile was registered at the new base and the name-response from the mobile confirms its identity.