On the Feasibility of Prefetching and Caching for Online TV Services: A Measurement Study on Hulu
Lately researchers are looking at ways to reduce the delay on video playback through mechanisms like prefetching and caching for Video-on-Demand (VoD) services. The usage of prefetching and caching also has the potential to reduce the amount of network bandwidth usage, as most popular requests are served from a local cache rather than the server containing the original content. In this paper, we investigate the advantages of having such a prefetching and caching scheme for a free hosting service of professionally created video (movies and TV shows) named “hulu”. We look into the advantages of using a prefetching scheme where the most popular videos of the week, as provided by the hulu website, are prefetched and compare this approach with a conventional LRU caching scheme with limited storage space and a combined scheme of prefetching and caching. Results from our measurement and analysis shows that employing a basic caching scheme at the proxy yields a hit ratio of up to 77.69%, but requires storage of about 236GB. Further analysis shows that a prefetching scheme where the top-100 popular videos of the week are downloaded to the proxy yields a hit ratio of 44% with a storage requirement of 10GB. A LRU caching scheme with a storage limitation of 20GB can achieve a hit ratio of 55% but downloads 4713 videos to achieve such high hit ratio compared to 100 videos in prefetching scheme, whereas a scheme with both prefetching and caching with the same storage yields a hit ratio of 59% with download requirement of 4439 videos. We find that employing a scheme of prefetching along with caching with trade-off on the storage will yield a better hit ratio and bandwidth saving than individual caching or prefetching schemes.
KeywordsVideo-on-Demand services Hulu Cache Prefetching
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- 1.Hulu, http://www.hulu.com
- 2.Netflix, http://www.netflix.com
- 3.Wikipedia on Hulu, http://en.wikipedia.org/wiki/Hulu
- 4.Endance DAG Network Monitoring Interface, http://www.endance.com
- 5.Liu, W., Chou, C.T., Yang, Z., Du, X.: Popularity-wise Proxy Caching for Interactive Media Streaming. In: Proceedings of LCN Conference, Tampa, Florida (2004)Google Scholar
- 6.Sen, S., Rexford, J., Towsley, D.: Proxy Prefix Caching for Multimedia Streams. In: Proceedings of IEEE INFOCOM (1999)Google Scholar
- 7.Wu, K.-L., Yu, P.S., Wolf, J.L.: Segment-based Proxy Caching of Multimedia Streams. In: Proceedings of the 10th International Conference on World Wide Web, pp. 36–44. ACM, New York (2001)Google Scholar
- 8.Zink, M., Suh, K., Gu, Y., Kurose, J.: Watch Global, Cache Local: Youtube Network Traffic at a Campus Network – Measurements and Implications. In: Proceedings of SPIE/ACM Conference on Multimedia Computing and Networking (MMCN), Santa Clara (2008)Google Scholar