| The Internet has evolved to become a critical commercial infrastructure for service delivery. However, the Internet being an enormous, highly-dynamic, heterogeneous, and untrusted environment raises several challenges for building Internet-scale services (such as content delivery) with good scalability, efficiency, agility and security. In this thesis, we explore these issues by developing a scalable, adaptive and network-aware infrastructure for efficient content delivery, namely Scalable Content Access Network (SCAN).; SCAN has four components: object location, replica placement and update multicast tree construction, replica management, and overlay network monitoring services.; First, we propose a novel simulation-based network Denial of Service (DoS) resilience benchmark, and apply it to evaluate and compare the centralized, replicated, and emerging distributed object location services.; Second, we propose the first algorithm that dynamically places close to optimal number of replicas while meeting client QoS and server resource constraint, with overlay network topology only.; Third, we apply cooperative clustering-based replication to SCAN, which achieves comparable users' perceived performance to the conventional CDNs, while having only 4--5% of replication and update traffic, and 1--2% of the computation and replica management cost.; Fourth, to provide a general foundation for applications to take advantage of network awareness, we develop a scalable overlay network measurement and monitoring system with two components: Internet Iso-bar for latency estimation, and TOM (Tomography-based Overlay network Monitoring) for loss rate estimation.; TOM selectively monitors and measures the loss rates of a minimal basis set of O(n log n) linearly independent paths, and then applies them to estimate the loss rates of all other paths.; Finally, to demonstrate the effectiveness of the monitoring services, we develop a adaptive overlay streaming media system which leverages our monitoring services for real-time path congestion/failure information, and an overlay network for adaptive packet relaying and buffering within the delivery infrastructure. (Abstract shortened by UMI.)... |
