Load and proximity aware request-redirection for dynamic load distribution in peering CDNs

Abstract

Peering between Content Delivery Networks (CDNs) endeavors to ensure that each user is served by an optimal Web server in terms of network cost, even under heavy load conditions. Therefore, a dominant factor for the success of peering between CDNs is to perform load distribution to handle highly skewed loads. In this paper, our approach for dynamic load distribution adopts a request-redirection mechanism by taking traffic load and network proximity into account. The load distribution strategy reacts to overload conditions, at a time instance, in any primary CDN server(s) and instantly distributes loads to the target servers, minimizing network cost and observing practical constraints. In this context, we formulate the resulting redirection strategy and perform extensive simulations to demonstrate the novelty of our approach. We show that our approach is effective to handle high load skews, and thus achieve service "responsiveness". We also perform a sensitivity analysis to reveal that our redirection scheme outperforms other alternatives. © 2008 Springer Berlin Heidelberg.