A Scalable Color-Based Caching Scheme in Telco-CDNs

Internet traffic is growing quickly, and it is majorly contributed by the proliferation of video services. Content Delivery Networks (CDNs) reduce the video traffic by storing replicas of videos in their cache servers. Nonetheless, the cache servers are usually located outside Internet Service Providers (ISPs). This implies that CDNs cannot reduce the video traffic inside ISP networks. To mitigate this issue, many ISPs build their own CDNs called Telco-CDNs. Genetic Algorithm-based caching is deemed the best approach in terms of traffic reduction. However, it is not practical since its computation time to generate content allocations is extremely long even when using a cluster. A color-based approach was devised to help overcome the drawback at the expense of its increase in traffic. Nevertheless, in case the number of content categories or requests proliferates quickly, the approach also has the same limitation like the Genetic Algorithm-based caching. To resolve the limitation, we propose two novel techniques to hamper the increase in the computation time. One is able to cope with the situation when the number of content categories increases while the other can deal with the circumstance when the number of requests rises. The empirical results show that the computation time is reduced 5x for the former and 7x for the latter at the expense of 1% and 12% increase in traffic for a problem of 5,000 contents, respectively.