Recent years have seen a tremendous growth of interests in streaming continuous media such as video over the Internet. This would create an enormous increase in the demand on various server and networking resources. To minimize service delays and to reduce loads placed on these resources, we propose an Overlay Caching Scheme (OCS) for overlay networks. OCS utilizes virtual cache structures to coordinate distributed overlay caching nodes along the delivery path between the server and the clients. OCS establishes and adapts these structures
dynamically according to clients' locations and request patterns. Compared with existing video caching techniques, OCS offers better performances in terms of average service delays, server load, and network load in most cases in our study.