Patent ID: 8805787

Claim:
A method, comprising: generating a list of current files stored in a user device, wherein the list of current files includes unique file identifiers, each associated with a corresponding one of the current files; sending the list of current files from the user device to one of a plurality of proxy devices, wherein the one of the plurality of proxy devices is selected based on a proximity of each of the plurality of proxy devices to the user device; receiving, at the user device, a copy list generated by the one of the plurality of proxy devices by comparing the list of current files to a list of previously copied files including unique file identifiers, each associated with a corresponding one of the previously copied files; sending, via a first communication link, the files listed in the copy list from the user device to the one of the plurality of proxy devices, wherein the first communication link introduces no errors into first ones of the sent files and introduces one or more errors into second ones of the sent files, and wherein the one of the plurality of proxy devices transmits the first ones of the sent files determined at the one of the plurality of proxy devices to be valid and not the second ones of the sent files determined at the one of the plurality of proxy devices to be invalid, via a second communication link to a backup network device separate from the plurality of proxy devices; receiving, from the one of the plurality of proxy devices, an error message indicative of the second ones of the sent files determined at the one of the plurality of proxy devices to be invalid based on the one or more errors; recovering, responsive to the error message, the first communication link; and resending, via the recovered first communication link, the second ones of the sent files to the one of the plurality of proxy devices, wherein the one of the plurality of proxy devices transmits the re-sent files via the second communication link to the backup network device.