Social Graph-Based Partitioning and Distribution for OSN Content Caching and Proactive Delivery

The continued growth of Internet traffic associated with the popularity of online social networks (OSNs) raises the possibility that knowledge of the underlying social graph connecting users may be exploited to enhance content distribution and delivery. In our previous work, we found that partitioning OSN users and their data based on their social graph, and using the partitioning as basis for content placement decisions across cache servers yield significant improvements over randomly-partitioned implementations. In this paper we go beyond content placement and use the same partitioning scheme to push updates across distributed caches to maintain consistency in OSN state. To avoid making singular assumptions on the degree to which user interaction patterns are influenced either by social considerations or content popularity, we parameterized our experiments to determine the impact of various interaction mixes on different cache designs. We found that in the new hybrid scheme that combines "socially-aware" cooperative content placement, on one hand, with social graph-driven proactive content delivery on the other, significant performance benefit continues to be driven by the former rather than the latter. Consequently, the hybrid scheme is likewise sensitive to the granularity of graph partitioning, which in turn dictates cache sizes and the number of cache servers.