AViC: A Cache for Adaptive Bitrate Video

Video dominates Internet traffic today. Users retrieve on-demand video from Content Delivery Networks (CDNs) which cache video chunks at front-ends. In this paper, we describe AViC, a caching algorithm that leverages properties of video delivery, such as request predictability and the presence of highly unpopular chunks. AViC's eviction policy exploits request predictability to estimate a chunk's future request time and evict the chunk with the furthest future request time. Its admission control policy uses a classifier to predict singletons - chunks evicted before a second reference. Using real world CDN traces from a commercial video service, we show that AViC outperforms a range of algorithm including LRU, GDSF, AdaptSize and LHD. In particular LRU requires up to 3.5x the cache size to match AViC's performance. Further, AViC has low time complexity and has memory complexity comparable to GDSF.