Collaborative caching in content-oriented networks

The content-oriented network is becoming a reality with enormous amount of contents such as high-definition videos and software packages being spreading across the entire network as the daily routine. Such an explosive demand on the content delivery has recently gained much attention with the increasing user popularity and the successful deployment of commercial systems. However, this also poses significant challenges on the existing network infrastructure due to the tremendous consumption of resources such as storage, link bandwidth and the involved network traffic cost. With the large amount of contents available in the entire network, how to efficient utilize the network capacity is becoming a critical problem in both research and practice.;The deployment of cache servers in content-oriented networks can help to alleviate the resource constrains, and also helps to move the content closer to end users with better user experiences. Cached contents are usually located close to users, which can greatly reduce the traffic on the network backbone with the improved performance. It also offloads the involved traffic cost by limiting the unregulated inter-domain traffic. Despite a large amount of existing caching mechanisms for conventional web applications, relatively little has been done in the cache design for content-oriented networks, which exhibit unique traffic features and user behaviors. Furthermore, there is a great potential as well as challenge in exploring collaboration among cache servers given their autonomous property and distributed nature.;In this thesis, we address the design and the analysis of collaborative caching mechanisms in several scenarios within content-oriented networks. We first discuss caching strategies in structured content-oriented networks. Based on the hierarchical topology derived from real-world Internet Protocol television (IPTV) systems, we propose efficient mechanisms to explore the capacity of the existing system infrastructure. We then investigate collaborative caching mechanisms in peer-to-peer (P2P) applications, considered as typical unstructured content-oriented networks. We specifically focus on eliminating the tremendous inter-domain traffic cost, with respect to dynamic P2P traffic patterns, peering policies and cache server capacity constraints. We then design incentive mechanisms for the cache collaboration in wireless multimedia networks, in order to promote the potential collaboration among selfish cache servers belonging to different administrative domains.;Through studies in both structured and unstructured content-oriented networks, we observe that the overall system performance can greatly benefit from the proposed collaborative caching mechanisms while the involved traffic cost is also minimized. Caching decisions are made based on specific topological properties, capacity constraints and optimization objectives. The analysis on incentive mechanisms further improves the practicability of proposed mechanisms.