Design and evaluation of a scalable and reliable P2P assisted proxy for on-demand streaming media delivery

To efficiently deliver streaming media, researchers have developed technical solutions that fall into three categories, each of which has its merits and limitations. Infrastructure-based CDNs with dedicated network bandwidths and hardware supports can provide high-quality streaming services, but at a high cost. Server-based proxies are cost-effective but not scalable due to the limited proxy capacity in storage and bandwidth, and its centralized control also brings a single point of failure. Client-based P2P networks are scalable, but do not guarantee high-quality, streaming service due to the transient nature of peers. To address these limitations, we present a novel and efficient design of a scalable and reliable media proxy system assisted by P2P networks, called PROP. In the PROP system, the clients´ machines in an intranet are self-organized into a structured P2P system to provide a large media storage and to actively participate in the streaming media delivery, where the proxy is also embedded as an important member to ensure the quality of streaming service. The coordination and collaboration in the system are efficiently conducted by our P2P management structure and replacement policies. Our system has the following merits: 1) It addresses both the scalability problem in centralized proxy systems and the unreliable service concern by only relying on the P2P sharing of clients. 2) The proposed content locating scheme can timely serve the demanded media data and fairly dispatch media streaming tasks in appropriate granularity across the system. 3) Based on the modeling and analysis, we propose global replacement policies for proxy and clients, which well balance the demand and supply of streaming data in the system, achieving a high utilization of peers´ cache. We have comparatively evaluated our system through trace-driven simulations with synthetic workloads and with a real-life workload extracted from the media server logs in an enterprise network, which shows our design significantly improves the quality of media streaming and the system scalability.