Design, analysis and applications of a scalable multicast protocol for next-generation internet.

摘要

The next-generation Internet will accommodate various multimedia applications over a common IP-based transport infrastructure. Many multimedia services require a scalable and efficient multicast mechanism which is capable of disseminating the shared data to widely distributed destinations. The traditional IP multicast is bandwidth efficient in data delivery but not scalable in managing the multicast tree. The more recent overlay multicast establishes the data-dissemination structure at the application layer, however, induces redundant traffic at the network layer.;In this thesis, a multicast scheme based on the concept of application-oriented networking (AON) is proposed, where the essence is to integrate application intelligence into the network. The protocol is formally termed as application-oriented multicast (AOM). With AOM, each data packet carries explicit destinations information, instead of an implicit group address, to facilitate the multicast data delivery; each router leverages the unicast IP routing table to determine necessary multicast copies and next-hop interfaces. The fundamental issue is that the bandwidth overhead for such explicit addressing must be limited, since it is impractical to attach all the destination addresses to each packet. In the elaborated design, the Bloom filter technique is utilized to constrain the storage and bandwidth overhead of AOM protocol. AOM is scalable in routing and forwarding; its localized group identifier (ID) allocation scheme provides much management flexibility. Performance of the proposed multicast mechanism is demonstrated through ns-2 simulation results and theoretical analysis. Moreover, the proposed AOM protocol is applied to IPTV service, with the focus on reducing the channel zapping response time. A recently-proposed channel zapping acceleration scheme based on time-shifted sub-channels (TSS) is analyzed from a theoretical perspective to understand its fundamental performance and properties. AOM is proposed to implement the TSS-based model, which achieves higher efficiency and robustness compared with IP multicast based implementation. Furthermore, this thesis develops a generic AON simulation framework (GAON) compatible with ns-2 simulator to facilitate the research on next-generation Internet. With GAON, developers could conveniently deploy their protocols in the ns-2 environment. The interconnection of the developer-defined protocol agent and the built-in ns-2 utilities are handled by the GAON.