The rapid increase of content delivery over the Internet has led to the proliferation of content distribution networks (CDNs). CDNs might consist of both managed infrastructure as well as peer-to-peer (P2P) elements. Our first focus in this talk is on CDN management algorithms for request routing, content placement, and eviction. We abstract the system of frontend source nodes and backend caches of the CDN in the likeness of the input and output nodes of a switch. In this model, queues of requests for different pieces of content build up at the source nodes, which route these requests to a cache that contains the requested content. For each request that is routed to a cache, a corresponding data file is transmitted back to the requesting source across links of finite capacity. Caches are of finite size, and the content of the caches can be refreshed periodically. Can we design distributed policies for joint request routing, content placement and content eviction with the goal of small user latencies? In the second part of the talk, we attempt to utilize awareness of demand for a piece of content in the interest of efficient resource usage. Suppose that we can use a managed CDN and/or a P2P network for content distribution. What would the latency experienced by users look like? We use the Bass model of demand evolution to compare a hybrid of P2P and a centralized client-server approach against each method acting alone. Can we determine how to combine managed infrastructure and P2P methods so as to minimize the latency experienced by users while maintaining low server utilization?
Thursday, October 20, 2011
Free and open to the public