On Tue, Jun 9, 2020 at 1:39 PM Nico Williams <nico@xxxxxxxxxxxxxxxx> wrote:
> * Some folks have assumed the TCP checksum, at 16 bits, misses an error
> about 1 in 2^16 times. That's not correct. There are classes of errors
> that TCP catches 100% of the time (e.g. single-bit errors). There are also
> classes of errors that the TCP checksum misses about 1 in 2^10 times. This
> latter is because the TCP checksum is not terribly good -- a better
> designed checksum would miss only about 1 in 2^16.
2-bit errors do happen.
I'm not sure what the 2-bit errors happen point is. Lest someone imagine that bit errors are the issue...
Lots of errors happen. 1 bit, 2-bit, byte, entire packet buffers trashed, bytes/words/sequences forced to all 0s and all 1s, chunks of packets erased or duplicated.... Essentially anything that can go wrong in a middlebox/router showed up -- data line timing errors, bad memory (in varying sizes), pointers getting trashed such that other random data gets added/deleted, etc.
Table 3 my 2000 paper with Jonathan Stone lists a huge range of errors in that error and few of them were bit errors.
Craig
Craig
Craig
*****
Craig Partridge's email account for professional society activities and mailing lists.
