Studies On IP Multicast In Mobile Internet

Internet has become the most important information infrastructure in modern society, and an important component in our lives. Mobile Internet can extend the network services even when people are moving and it has wide development prospects. Meanwhile, IP multicast can efficiently deal with multi-destinations delivery and release the burden of replications from the source, so it has attracted enough attentions of researchers. Providing multicast in mobile Internet can make better use of efficiency, and it will be fruitful to bring these two technologies together. But the structure of mobile Internet is more complex, and the handoff of mobile nodes will cause the joining and leaving behaviors occur much more frequently, so it is challenging when providing multicast for mobile nodes. It is a new research area and still lacks of architecture, algorithm and protocol. In this thesis, the multicast in mobile Internet (mobile multicast for short) is studied in details. The main research works and conclusions are as follows:1. The difficulties of providing multicast in mobile Internet are analyzed, and then a comprehensive overview of existing researches on mobile multicast is provided.2. A hierarchical mobile multicast framework based on domain agent is proposed. Some key techniques are proposed, such as hierarchical multicast model, cross-domain multicast group transform mechanism, hierarchical multicast group management, and hierarchical multicast tree maintenance mechanism. These techniques make sure that the framework achieves high scalability on network scale, heterogeneous network environments and heterogeneous multicast routing protocols. Then an integrated performance evaluating theory is proposed. It evaluates the mobile multicast algorithms from the aspects of both multicast users and the whole Internet. This integrated performance evaluating criteria can be applied to design, select and improve the mobile multicast algorithms.3. Based on the hierarchical mobile multicast framework, the author proposes the Fast Multicast Handoff Based Hierarchical Mobile Multicast Algorithm (FHMM). The simulation results show that FHMM achieves better performance on both sides of multicast users and whole network. It is a comprehensive and efficient solution for mobile multicast.4. The author finds out and proves that mobility makes the stability problem of multicast tree more serious. In order to find out how the various elements impact on the stability factor, five elements are investigated. They are mobile multicast algorithm, the ratio of the number of mobile nodes and network size, the mobility model, the move speed and the power range. The main correlative elements are found which gives references when designing mobile multicast algorithms.5. In order to improve the stability of FHMM algorithm, the idea of motion prediction is introduced, and a new algorithm called P-FHMM is proposed. The simulation results show that P-FHMM can improve the stability of multicast tree remarkably while maintaining high efficiency and low packet loss percentage.6. A simulation system to investigate mobile multicast algorithms has been developed. It can be easily configured and managed, and has the merit of high scalability.