Although many overlay and P2P approaches have been proposed to assist large-scale live video streaming, how to ensure
service quality and reliability still remains a challenging issue. Peer dynamics, especially unscheduled node departures,
affect the perceived video quality at a peer node in two ways. In particular, the amplitude of quality fluctuations and the
duration for which stable quality video is available at a node heavily depend on the nature of peer departures in the system.
In this paper, we first propose a service quality model to quantify the quality and stability of a video stream in a P2P
streaming environment. Based on this model, we further develop tree construction algorithms that ensure that every peer
in the collaborative network receives a video stream with a statistical reliability guarantee on quality. A key advantage
of the proposed approach is that we can now explicitly control the quality and stability of the video stream supplied to
every node. This is the fundamental difference of our approach from existing approaches that provide stream stability by
over-provisioning resources allocated to every peer. Also, the proposed tree construction schemes decide the position of
a node in the delivery tree based on both its estimated reliability and upstream bandwidth contribution while striving to
minimize the overall load on the server. Our simulations show that our algorithms use the server resources very efficiently
while significantly improving the video stability at peers.
In this paper, we propose a novel loopback approach in a two-level streaming architecture to exploit collaborative client/proxy buffers for improving the quality and efficiency of large-scale
streaming applications. At the upper level we use an overlay to deliver video from a central server to proxy servers, at the lower level a proxy server delivers video with the help of collaborative caches. In particular, a proxy server and its clients in a local domain cache different portions of a video and form delivery loops. In each loop, a single video stream originates at the proxy, passes through a number of clients, and is passed back to the proxy. As a
result, with limited bandwidth and storage space contributed by collaborative clients, we are able to significantly reduce the requirements of network bandwidth, I/O bandwidth, and cache space at a proxy. Furthermore, we develop local repair schemes to address the client failure issues for enhancing server quality and eliminating most repairing load at servers. For popular videos, our local repair schemes are able to handle most of single-client failures without service disruption and retransmissions from a central server. Our analysis and simulations have shown the efficacy of loopback in various settings.