Selective cache digest exchange mechanism for group based Content Delivery Networks

Abstract

Content Delivery Networks (CDNs) are one of the most important techniques used for WAN optimization. CDN service providers install a cache server/distribution server close to the end users of the original data. The data from the original server of the CDN client is taken and pushed into the network of distribution servers, to make sure end-user is served from the nearest distribution server. Many algorithms were proposed for coordination between distribution servers, to exchange the information regarding content between distribution servers in the CDN environment with minimal error or minimal usage of resources. Different coordinating algorithms that currently exist include Internet Cache Protocol (ICP), cache digest algorithms and more. Most of these algorithms lacked an important factor of providing certainty of the information shared during process. Due to this issue, most algorithms use if-modified packets to validate information, sending them whenever a user requests CDN service. In this research work, a certainty factor was introduced and its effect on the environment is shown. Simulation was done to show the effect of using the certainty factor; simulation was also done with an increasing number of servers in the group, to show the scalability of the approach.