Presentation on theme: "Cost-Based Cache Replacement and Server Selection for Multimedia Proxy Across Wireless Internet Qian Zhang Zhe Xiang Wenwu Zhu Lixin Gao IEEE Transactions."— Presentation transcript:
Cost-Based Cache Replacement and Server Selection for Multimedia Proxy Across Wireless Internet Qian Zhang Zhe Xiang Wenwu Zhu Lixin Gao IEEE Transactions on Multimedia, August 2004
Outline Introduction Multimedia Proxy Architecture Cost-Based Cache Replacement in the Single-Server Environment Sever Selection in Multiple Server Environment Simulation Conclusion
Multimedia Proxy Architecture
Scalable Video Structure Layer 0 Layer 1 Layer 2 Video Object
Key effectiveness of the proxy cache Replacement Policy Cache gain : Video objects contribution of the proxy to achieve high performance Cost-Based Cache Replacement
Performance metrics of traditional replacement algorithm Hit ratio Byte hit ratio Performance metrics of cost-based replacement algorithm Video quality Network cost saving Start-up delay Cost-Based Cache Replacement
Multiple objectives for multimedia proxy Different portion of continuous media have different characteristics Reduce the consumption of network resource by reducing the throughput of Internet transmission between proxy and server Cache a video prefix in order to reduce startup latency for streaming.
Different layer have different video-quality impact. Video-Quality Revenue Rate Rmse(v) [root-mean-square error] : represents the quality of video object. f (v) : request frequency of the video object Redundant video object
Network-Saving Revenue Rate Objective : reduce the consumption of network resource between proxy and server Throughput Revenue Rate : Size (v) : size of the video object Dist (RTT(v)) : distance between the server and proxy Network-Utilization Revenue Rate : μ(v, t) : network utilization for video v at time t
Startup Latency Revenue Rate Latency between remote video server and proxy dominates end-to-end latency. Prefix caching is an effective way to reduce startup latency for end clients.
Cost-Based Replacement Policy Total revenue rate of video object v Total revenue rate of redundant video object v R Cache Gain
Cost-Based Replacement Policy in Multiple Server : integration network utilization for video v at time t Video with fewer replicas gets a higher network-utilization revenue reate (Single Server) (Multiple Server)
Server-Selection Algorithm Multimedia proxy measures the potential revenue of each candidate video server for the request.
Server-Selection Algorithm To perform load balance for consumed network resource Selection Gain To avoid the overload for the hot link while improving the utilization of the cold link
Multimedia proxy over wireless Internet where the data cache and computational cache were introduced considering the different characteristics of wireless and Internet links. For the single server case, novel cost-based replacement so as to improve all three aspects of performance, i.e., video quility. For the multiservers case, new cost-based server- selection policy for multimedia proxy to improve the video quality. Conclusion