US Patent 7558198 Method and apparatus for data transfer

A user will receive a variation of a particular file depending upon the type of network the user is currently accessing. More particularly, a user will typically receive a smaller version of a file when the user is accessing a low-bandwidth (low data rates) network, and can choose to receive a larger version of the file when the user accesses a high-bandwidth (high data rates) network. When several networks are available to the user either simultaneously or sequentially, the user will receive the optimum file version based on cost and quality preferences in the former case and may receive multiple versions of the file in the later case, each increasing in quality.