A method comprising: initiating by a multi-mode mobile device a service in a first session in a first wireless network; detecting by the multi-mode mobile device a second wireless network supporting a different access network technology than the first wireless network; determining a Quality of Service requirement for the service, and completing pre-registration session establishment procedures by the multi-mode mobile device for a second session in the second wireless network for inter-technology handover when the service supported by the multi-mode mobile device includes at least one of a service sensitive to Quality of Service and real time service, the pre-registration session establishment procedures including authentication, authorization, and registration procedures, wherein after completion of the pre-registration session establishment procedures the multi-mode mobile device receives service from the first wireless network and remains dormant on the second wireless network; determining when handover is required; when handover is required, handing over from the first wireless network to the second wireless network using the established pre-registration session, without having to complete further network entry and session registration/establishment procedures; and further comprising not completing pre-registration session establishment procedures by the multi-mode mobile device for the second session in the second wireless network when the determined service supported by the multi-mode mobile device does not include at least one of a service sensitive to Quality of Service and real-time service. initiating by a multi-mode mobile device a service in a first session in a first wireless network; detecting by the multi-mode mobile device a second wireless network supporting a different access network technology than the first wireless network; determining a Quality of Service requirement for the service, and completing pre-registration session establishment procedures by the multi-mode mobile device for a second session in the second wireless network for inter-technology handover when the service supported by the multi-mode mobile device includes at least one of a service sensitive to Quality of Service and real time service, the pre-registration session establishment procedures including authentication, authorization, and registration procedures, wherein after completion of the pre-registration session establishment procedures the multi-mode mobile device receives service from the first wireless network and remains dormant on the second wireless network; determining when handover is required; when handover is required, handing over from the first wireless network to the second wireless network using the established pre-registration session, without having to complete further network entry and session registration/establishment procedures; and further comprising not completing pre-registration session establishment procedures by the multi-mode mobile device for the second session in the second wireless network when the determined service supported by the multi-mode mobile device does not include at least one of a service sensitive to Quality of Service and real-time service.