The exponential growth of Internet-based services together with various access technologies and a wide range of mobile-networked devices have allowed users to be ‘always connected'. However, no single technology can provide ubiquitous coverage and high throughput across all geographical areas and hence require inter-working of various heterogeneous access networks and technologies, a concept for the 4th generation networks. To provide true mobility, service providers (Telco) need a management system to authenticate and authorise users, to provide agreed-upon services and to negotiate roaming agreements with other service providers at real time. This book presents a new model and its architecture for centralised management of networks based on business-level policies. This book also implements a new model of an intelligent mobile client to automatically detect, select and handoff across best available network, hence providing always-best-connected services to mobile users. This work should be especially useful to professionals in network management and mobile field considering to provide end-to-end services to their users.