A fixed & mobile converged access network conducting a wide range of wireless and wireline access technologies with different performance capabilities becomes reality in Next Generation Network (NGN) using Internet Protocol (IP) for data transport. How the mobility of user terminals connected to a heterogeneous access network will be enabled as well as how the network resources, primarily strongly limited radio resources. will be distributed among demanding subscribers are important and challenging research topics today. The majority of the research on the mobility management systems tackles the problems of a topologically correct IP packet delivery to and from mobile terminals moving across access nodes while mechanisms for resource management are investigated separately. This thesis presents a new Integrated Mobility and Resource Management Mechanism (lM› RMM). a network oriented framework enabling intelligent Network Load Balancing improving the performance of NGN applications. Using IMRMM architecture. input triggers for the mobility mechanism enabling a correct data exchange with mobile nodes are enabled by an observation function monitoring the Quality of Service (QoS) level provided for different applications. Observation functions are proposed to be installed on access nodes which only can determine the performance that may be provided for a particular mobile node or for a particular traffic type. The main contribution of this thesis is the introduction of a new functional network architecture used for an intelligent distribution of the IP flows between available access nodes. The resource control is implemented by the assignment of different IP flows to different access nodes. The results of the QoS observation are used as triggers for a network located Mobility Management Engine initiating re-distribution of the network load between access nodes. Using a novel Layer 2 (L2) based mobility solution a simultaneous usage of multiple network interfaces for different IP flows and their fast re-switching between network interfaces is enabled. Functional elements of the developed IMRMM architecture as well as of the new L2 based mobility management system are defined in detail in this thesis. Extensive simulation based investigations are used to compare the quality enabled by the new IMRMM architecture with the quality provided by using traditional algorithms for the selection of access nodes. The obtained results clearly show the benefits of the proposed IMRMM and of the developed handover algorithms.