I would suggest that you read this: https://web.mit.edu/Saltzer/www/publications/endtoend/endtoend.pdf https://web.mit.edu/Saltzer/www/publications/endtoend/end

I would suggest that you read this: https://web.mit.edu/Saltzer/www/publications/endtoend/endtoend.pdf https://web.mit.edu/Saltzer/www/publications/endtoend/endtoe... Errors can show up any time, and usually show up between the parts that checksums correct. On the wire, TCP protects you with a (weak) checksum. Off the wire, your computer and filesystem can still screw things up. Even CPU bugs can do this.