Providing efficient and reliable end -host multicast services on the Internet.

Abstract

The fast emergence of P2P services, such as file sharing, Internet phone service, and video streaming demonstrates the potential of P2P network to deliver large files and high quality streams to a large audience. The successful commercialization of P2P audio services such as Skype illustrates the business potential of P2P services. End-host multicast is a natural protocol for P2P applications that deliver data in a one-to-many fashion. In this thesis, we present a comprehensive solution for providing efficient and reliable end-host multicast services on the Internet. Existing approaches have several drawbacks in their protocol design. First, existing approaches lack a systematic study of overlay construction. Second, existing published protocols focus on the overlay design itself without taking into account the heterogeneity of Internet hosts and network conditions. Finally, current efforts only focus on data dissemination from a single source. Supporting multi-source applications with current solutions may lead to sub-optimal performance. To address these drawbacks, we first conduct a systematic study on the effect of adding new links to an overlay and present an effective heuristic to reduce latencies between multicast group members. We then conduct empirical experiments on the Internet to collect statistics on user profiles of existing P2P systems. We discover that the prevalence of guarded hosts---hosts behind firewalls and NAT gateways---interferes with overlay construction, since guarded peers cannot accept incoming connections from other peers. Taking into account the existence of guarded hosts, we enhance our overlay improvement heuristic and develop the <italic>e</italic>* protocol to accommodate a large number of guarded hosts while achieving low average end-to-end latencies. Under realistic scenarios involving guarded hosts, <italic> e</italic>* can reduce average end-to-end latency on the overlay by 28-61% compared to existing protocols. We also improve the resiliency of overlays to membership churn, node failures, and targeted attacks. Finally, we implement our protocol and develop a video/audio multicast system that has been used to stream several workshops and conferences live online. Our experience with the deployment of our multicast tool confirms that our protocol can provide efficient and reliable overlay services on the Internet.