TR-05-5.pdf
``DISC: Dynamic Interleaved Segment Caching for Interactive Streaming Accesses",
Lei Guo, Songqing Chen, Zhen Xiao, and Xiaodong Zhang
Proceedings of the 25th International Conference on Distributed Computing
Systems (ICDCS'2005), Columbus, Ohio, June 6-9, 2005.
Abstract
As streaming media objects are becoming widely used on the Internet, the
demand of interactive requests to these objects has increased dramatically.
Typical interactive requests include fast forward and direct jump from one
point to another. Unfortunately, existing streaming proxies are usually
designed for sequential accesses and hence cannot support interactive
requests effectively. Previously, a few solutions have been proposed to
maintain additional data structures in the proxy to support some interactive
operations (such as fast forward). However, they are not able to support
jumps, which are among the most common interactive requests from the clients.
In this work, we present our analysis of the media workload collected from
thousands of broadband home users through a major ISP. Our analysis shows
that jump accesses (48%) and pauses (51%) are the dominant client interactive
requests and that jump accesses often suffer serious delays due to slow
buffering through the network. To support jump accesses effectively, we
propose a novel caching algorithm -- DISC (Dynamic Interleaved Segment
Caching), which trades cache performance for response time to client
interactive requests. In this algorithm, segments of a media object are
cached dynamically according to the client access patterns. It can support
direct jumps efficiently while ensuring in-time prefetching of uncached
segments for sequential accesses. Trace-driven simulations demonstrate that
DISC outperforms other caching schemes significantly for interactive requests
with only a small degradation in cache performance.