CDN bandwidth allocation in weakly interconnected networks

Large-scale Internet VoD services often adopt a hybrid overlay approach using both P2P and CDN to stream video content. When the underlay ISP network interconnection is weak, as the situation is found in China, it is important to provision the CDN bandwidth carefully in different ISP networks. Through measurement studies using real world data (from Tencent Video), it is found that users in large ISP networks can leverage more on P2P service, compared to the case for smaller ISP networks, and this is especially true during heavy load periods. We study systematic strategies for allocating CDN bandwidth given fixed total bandwidth purchasing budget, and the influence of P2P factor. We show that a more optimal strategy would bias towards allocating proportionally more CDN bandwidth to smaller ISP networks. This result from our model and analysis is validated by simulation. This problem has not been considered by past works and has practical implications for improving the operation of real-world VoD service providers.