In a future full service packet switched transport network, service quality equivalent to a circuit switched network should be supported. Recently, optical hybrid networks combining properties of circuit and packet switching have gained increased attention. We first comment on different network scenarios combining packet and circuit switching properties. We then describe in detail a network concept, entitled Optical packet switched Migration capable network with Guaranteed service (OpMiGua). Both a network model and a node model are described, and potential benefits are discussed. Guaranteed Service Transport (GST) traffic with fixed delay and zero packet loss is forwarded through a wavelength routed optical network. The remaining traffic is packets containing header control information, and is forwarded using packet switches. For the GST traffic, the OpMiGua concept ensures transparency, high reliability and high security. Because the GST traffic bypasses the packet switches, a reduction of the required size of the packet switch may be possible if transit-traffic is handled as GST traffic.