Content Routing and Lookup Schemes Using Global Bloom Filter for Content-Delivery-as-a-Service

摘要

The dramatic growth of user-generated contents (UGCs) transforms the digital media value chain, and stresses current content distribution network (CDN). In order to deliver UGCs in an efficient and economical fashion, we have proposed content-delivery-as-a-service (CoDaaS) by leveraging cloud computing technology. However, due to the exponential increase of Internet traffic (especially the UGCs), traditional hashing-based content routing and lookup scheme in CDNs suffers from high delay and consequent inefficient delivery. This paper introduces a global compressed counting BF (CCBF) into CoDaaS to address this issue. By equipping it with the global CCBF, our system is able to check early on for the existence of any specific content among all the peering surrogates, before any local checking on each cache node. Based on this global CCBF, we propose two content routing and lookup mechanisms (i.e., parallel and cut-through schemes) to reduce the delay for better user experience. The comparative performance of those approaches is verified via both mathematical modeling and experimental simulation. The results show that for light traffic load, the average response time can be saved by up to 65.2% compared with traditional methods. In addition, the impacts and overheads of different synchronization schemes are also quantified to provide valuable insight for further optimizations.