The last decade has seen explosive growth in the development of mobile applications. This has increased the demand on the wireless communication services. The capability to achieve wireless access anywhere, anytime, and anyplace has become common expectation as it provides significant flexibility and freedom in mobility. But to achieve global mobility in heterogeneous networks for any mobile device requires seamless connectivity using vertical handoff. Since none of the existing wireless frameworks provide practical solutions for vertical handoff. End-to-End Vertical Handoff (E2EVH) proposed in this paper offers a new concept to perform vertical handoff between heterogeneous wireless networks. To deliver network services without interruption, E2EVH present a novel design to monitor the network availability, it then picks the best accessible network for application layer. Since this approach relies only on existing technologies, deployed protocols and lightweight calculations, our approach can be easily implemented. In this paper, we present a proof-of-concept of E2EVH, and preliminary simulation results using OPNET Modeler 14.5. The results for different tested scenarios indicate the effectiveness of the proposed approach. Future research activities will integrate several additional wireless technologies that are presented and discussed in the paper.