A client side measurement scheme for request routing in virtual open content delivery networks

A content delivery network (CDN) routes a client´s request to an edge server that can best serve the content at the time. Effective request routing is heavily dependent on up-to-date information of server loads and the network condition. We propose a novel client side measurement scheme that measures both server load, and the network condition, in a single measurement. The scheme is distributed, does not require any modification to the clients, and is compatible with existing client and server software. By experimenting on the existing Internet, we demonstrate that this measurement metric is highly correlated with total page loading time. Combined with request-routing, our measurement method provides an efficient client request redirection system that is totally transparent to the content provider, and facilitates the deployment of virtual open CDNs.