Coordinated en-route web caching in transcoding proxies

Web caching, especially proxy caching, is an important technology for improving the efficiency of web content delivery. With the rapid growth of audio and video applications on the internet, caching media objects in transcoding proxies has become an important research topic in recent years. In this paper, we address the problem of optimally determining the locations for placing multiple versions of media objects in a network such that the objective specified is achieved. We present an original model, which makes caching decisions on all the en-route caches along the routing path in a coordinated way by integrating both media object placement and replacement policies, for this problem. We formulate this problem as an optimization problem and the optimal locations are obtained using a low-cost dynamic programming-based algorithm. We implement our algorithms and evaluate our model on different performance metrics through extensive simulation experiments. The implementation results show that our model significantly outperforms existing algorithms that consider media object placement or replacement at individual nodes only.