Hierarchical cache optimization in IPTV networks

In an IPTV network, Video on Demand and other video services generate a large amount of unicast traffic from the Video Hub Office (VHO) to subscribers and, therefore, require additional bandwidth and equipment resources in the network. To reduce this traffic and overall network cost, a portion of the video content (the most popular titles) may be stored in caches closer to subscribers, e.g., in a Digital Subscriber Line Access Multiplexer (DSLAM), a Central Office (CO), or in an Intermediate Office (IO). The problem is where and how much cache memory should be allocated in order to achieve maximum cost effectiveness. In this paper, we consider two approaches to solve this problem and analyze the factors that affect this solution. The analysis shows that hierarchical distributed caching can save significant network cost.