Download resumption continues a partially completed transfer instead of wasting bandwidth by downloading the file from the beginning after a timeout. section 11.1.2
A practical implementation follows this sequence:
- Set the HTTP Range header to request bytes beginning at the existing file length. section 11.1.2
- Retry timed-out requests, limiting attempts and tuning the client timeout for the environment. section 11.1.2
Resuming a large archive
A program downloads file.zip, retries up to 100 times, and reports the number of bytes ultimately stored. If a timeout interrupts the transfer, the next request starts at the existing file length. section 11.1.2
