An overlay content distribution network provides a consistent interface to enable the storage and retrieval of digital content at multiple storage providers (210). An allocator component (140) instantiates and destroys location and/or provider specific agent processes (240) which transfer digital content to and from the storage providers (210). Encoding agent processes (250) are geographically located near the storage providers (210) at which the content is to be stored. Content may be stored in a manner which guarantees content availability, each storage provider (210) being periodically probed by a Quality of Service (QoS) probes distributed within the network.