Investigation of multicast-based mobility support in all-IP cellular networks

To solve the IP mobility problem, the use of multicast has been proposed in a number of different approaches, applying multicast in different characteristic ways. We provide a systematic discussion of fundamental options for multicastbased mobility support and the definition and experimental performance evaluation of selected schemes. The discussion is based on an analysis of the architectural, performance-related, and functional requirements. By using these requirements and selecting options regarding network architecture and multicast protocols, we identify promising combinations and derive four case studies for multicast-based mobility in IP-based cellular networks. These case studies include both the standard anysource IP multicast model as well as non-standard multicast models, which optimally utilize the underlying multicast. We describe network architecture and protocols as well as a flexible software environment that allows to easily implement these and other classes of mobility-supporting multicast protocols. Multicast schemes enable a high degree of flexibility for mobility mechanisms in order to meet the service quality required by the applications with minimal protocol overhead. We evaluate this overhead using our software environment by implementing prototypes and quantifying handoff-specific metrics, namely, handoff and paging latency, packet loss and duplication rates, as well as TCP goodput. The measurement results show that these multicast-based schemes improve handoff performance for high mobility in comparison to the reference cases: basic and hierarchical Mobile IP. Comparing the multicast-schemes among each other the performance for the evaluated metrics is very similar. As a result of the conceptual framework classification and our performance evaluations, we justify specific protocol mechanisms that utilize specific features of the multicast. Based on this justification we advocate the usage of a source-specific multicast service model for multicast-based mobility support that adverts the weaknesses of the classical Internet any-source multicast service model.