SOP: A SIU-based Overlay Proxy Service for Peer-to-Peer Streaming

Abstract

The heterogeneity of end hosts poses a significant challenge in delivering asynchronous multimedia access services across overlay networks. Conventional cache-and-relay methods do not address either the link bandwidth constraint of end hosts, or the variable bit rate properties of video streaming. This work proposes an end-host based proxy service, called a Synchronization Interval Unit (SIU) based Overlay Proxy service (SOP), to enable smooth video playback and boost server capacity in a heterogeneous environment. SOP segments a movie into many SIUs, which are processed off-line with a proposed SIU-based smoothing algorithm (SSA) to handle the link and buffer constraints of heterogeneous end hosts. SSA generates a transmission profile for each SIU, including parameters relating to three resource constraint switching modes, BB, BR and BRR, between the download of each SIU to ensure smooth playback and to raise the cache hit rate. This study also develops four cache replacement strategies, namely, access-unaware, local access-aware, regional access-aware and global access-aware, each offering various levels of prefix, selective and cache-and-relay caching and caching cooperation among peers. A simulation experiment is performed to investigate the performance of SOP in cluster-based P2P networks. SSA with the access-aware caching approach can significantly improve the proxy hit rate, and can lower the server load by 15-35% server load at various user arrival rates. The simulation results indicate that SOP can relieve server load, and that the presented novel mechanisms can effectively improve the streaming service quality.