Effective media server placement strategies are critical for the quality and cost of multimedia services. Existing studies have primarily focused on optimization-based algorithms to select server locations from a small pool of candidates based on the entire topological information and thus these algorithms are not scalable due to unavailability of the small pool of candidates and low-efficiency of gathering the topological information in large-scale networks. To overcome this limitation, a novel scalable framework called NetClust is proposed in this paper. NetClust takes advantage of the latest network coordinate technique to reduce the workloads when obtaining the global network information for server placement, adopts a new$K$-means-clustering-based algorithm to select server locations and identify the optimal matching between clients and servers. The key contribution of this paper is that the proposed framework optimizes the trade-off between the service delay performance and the deployment cost under the constraints of client location distribution and the computing/storage/bandwidth capacity of each server simultaneously. To evaluate the performance of the proposed framework, a prototype system is developed and deployed in a real-world large-scale Internet. Experimental results demonstrate that 1) NetClust achieves the lower deployment cost and lower delay compared to the traditional server selection method; and 2) NetClust offers a practical and feasible solution for multimedia service providers.

The Chinese Internet, hosting the worlds largest population of Internet users, has largely remained as a black box due to the lack of large-scale measurement infrastructure and various other factors. In this paper, we characterize the Chinese Internet AS topology using measurements from both data and control planes. Our analysis emphasizes on the distinct characteristics of the regional network in comparison with the global Internet. To obtain a complete and accurate view, we combine multiple data sources in a complementary manner, including the traceroute conducted on both domestic servers and international Planetlab hosts at the data plane, as well as the RouteViews-based BGP routing information at the control plane. Our AS graph successfully captures 97% of the observable ASes in Chinese Internet. The topology is validated to be consistent with the well-known PFP model. Based on the measured topology, we further investigate the topological properties of the Chinese Internet by analyzing various graph-theoretic metrics. We found that the Chinese Internet preserves basic topological properties of global internet, such as power-law in node degree distribution and Pareto principle in international link distribution. This offers new insights for the Chinese Internet characterization and practical guidelines for future engineering optimization.

We present the design and deployment experiences with LiveSky , a commercial hybrid CDN-P2P live streaming system, which inherits the best of both CDN and P2P. We address several key challenges, including: 1) ease of integration with existing CDN infrastructure, 2) dynamic resource scaling while guaranteeing quality-of-service, 3) providing good user experience, ensuring network friendliness and upload fairness. LiveSky has been used for several large-scale live streaming events in China. Our evaluation results from real-world indicate that such a hybrid CDN-P2P system provides quality and performance comparable to a CDN and effectively scales the system capacity.

We present our design and deployment experiences with LiveSky, a commercially deployed hybrid CDN-P2P live streaming system. CDNs and P2P systems are the common techniques used for live streaming, each having its own set of advantages and disadvantages. LiveSky inherits the best of both worlds: the quality control and reliability of a CDN and the inherent scalability of a P2P system. We address several key challenges in the system design and implementation including (a) dynamic resource scaling while guaranteeing stream quality, (b) providing low startup latency, (c) ease of integration with existing CDN infrastructure, and (d) ensuring network-friendliness and upload fairness in the P2P operation. LiveSky has been commercially deployed and used for several large-scale live streaming events serving more than ten million users in China. We evaluate the performance of LiveSky using data from these real-world deployments. Our results indicate that such a hybrid CDN-P2P system provides quality and user performance comparable to a CDN and effectively scales the system capacity when the user volume exceeds the CDN capacity.