Fast Near-Optimal Algorithm for Delivering Multiple Live Video Channels in CDNs

Content Delivery Networks (CDNs) are confronted with a sharp increase in traffic related to live video (channel) streaming. Previous theoretical models that deal with streaming capacity problems do not capture the emerging reality faced by today's CDNs. In particular, a modern CDN has to deliver a large set of independent non-divisible data streams, which need to be either delivered in whole, or not delivered at all. This constraint is not addressed in previous works. In this paper we identify a new, discretized streaming model for live video delivery in CDNs. For this model we formulate a general optimization problem and show that it is NP-complete. Then we study a practical scenario that occurs in real CDNs. We present a fast, easy to implement, and near-optimal algorithm with performance approximation ratios that are negligible for large network. To our knowledge, these are the first results for the discretized streaming model, and have both practical and theoretical importance in a topic of growing criticality.