Resource discovery and request-redirection for dynamic load sharing in multi-provider peering content delivery networks

摘要

A constellation of Content Delivery Networks (CDNs), termed as peering CDNs, endeavors to guarantee adequate delivery performance when the incoming request load is overwhelming for a single provider alone. Each user is served by an optimal Web server in terms of network cost, even under heavy load conditions. Before it could be comprehended, appropriate resource discovery and request-redirection mechanisms, coupled with an optimal server selection strategy, should be in place to perform the distribution of highly skewed loads, in this paper, we devise an effective load distribution strategy by adopting distributed resource discovery and dynamic request-redirection mechanisms, 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 exercise an asynchronous resource discovery protocol, reminiscent of the public/subscribe notion, and formulate the resulting redirection scheme. Extensive simulation analyses demonstrate the novelty of our approach. In particular, we show that our approach is effective to handle high load skews by preserving locality, and thus achieve service "responsiveness". We also perform a sensitivity analysis to reveal that our redirection scheme outperforms other alternatives to handle peak loads.