Performance and dimensioning of a hierarchical video storage network for interactive video services

This paper examines a network architecture designed to offer interactive video services to residential subscribers. Its main feature consists in the possibility of storing heavily requested material in video ''cache'' locations at the local switch level. Various policies for the management of the resulting hierarchical storage system are defined and their effectiveness, in terms of success ratio of the local accesses, is evaluated via simulation. A simple evaluation of the cost trade-off between distributing video programs in local memories and keeping them in a centralized video server is carried out as well, considering both leased line and switched line solutions for long distance transmission. The difference due to the non stationary behaviour of the user requests is also evaluated.