Easier and more reliable ISO downloads, with error correction

Phillip Susi psusi at cfl.rr.com
Thu Nov 8 20:02:06 UTC 2007

Lars Wirzenius wrote:
> The error checking in the TCP/IP layer is usually sufficient, but not
> always. The checksum is short enough (32 bits, if I remember correctly)
> that errors can creep in. I have had it happen at least once to me.
> Unfortunately, the errors are more likely the more you download, and the
> more traffic there is -- meaning that at release time, for example,
> things are most likely to break, when people download huge ISO files.

There is no error correction at the TCP/IP layer.  The check sum is only 
for the headers and only performs error detection.  It is the underlying 
links ( your modem ) that have at least one layer of error detecting and 
correcting codes, and they have an exceedingly high success rate.

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