As successors of IP multicast, application-layer multicast and overlay networks have become two very important technologies in the current Internet that promise to provide a highly scalable platform for concurrent delivery of information to large groups of Internet users. This project focuses on next-generation overlay networks and studies the problem of building a distributed, self-organizing content distribution architecture for real-time video streaming services. Unlike previous approaches, our work does not rely on delay as the metric of distance, but rather utilizes the topological and routing structure of the existing Internet to compute distances and create local topologies. Using topologically aware discovery of the neighborhood of each replica server, nodes build efficient meshes for replication of static content and construct self-organizing multicast overlay trees for real-time streaming of live video material.
A special attention is paid to making sure that the entire architecture is highly scalable and suitable for practical use over the existing Internet. Once installed, each node in the proposed content distribution network (CDN) automatically discovers its location in the Internet, attaches to the control tree of the CDN structure, and finds other nodes in its neighborhood. The information in the control tree contains a scalable aggregation of all independently discovered views of the Internet by the nodes of the CDN network. Using this control tree, the nodes quickly build an overlapping set of neighborhood meshes that reach the main data server. Arriving end-users are efficiently directed to the nearest cache based on their location in the Internet and network clusters already discovered by the individual cache nodes. To avoid packet loss and to control the flows along the branches of the multicast tree, we investigate new congestion control methods for video streaming that allow smooth playback and remain stable under delayed feedback from the network.
CDNs emerged as a crucial part of the existing web infrastructure and already improve the response time, as well as the throughput, of many Internet downloads. Future CDNs that support video streaming will deliver a scalable platform for distributing live and pre-recorded video programs to end-users and will greatly improve the current ability of the society to disseminate information.
The proposed research activities will be integrated in the network course curriculum. This will enable students to gain deep understanding of the architectural design issues related to peer-to-peer networking and content distribution networks.
