The last time I saw a comparision of checksum algorithm strengths was back in the OSI days when the IP checksum was compared to the OSI Fletcher checksum (my memory is that the IP checksum came in second.)
um, well, it was certainly behind the Fletcher checksum; the IP and TCP checksums are trivial to beat - you can literally swap any two 16 bit words without fear. The Fletcher checksum isn't as strong as a CRC, but I did see its strength compared positively with a CRC. The XNS checksum (one's complement sum, like IP, but with rotation) fell somewhere in between.
As I understood the discussion, it wasn't so much about getting a better error check as it was adding FEC, however. Even a 32 bit CRC loses its value above 10^5 bits, and we're talking about 10^5 *bytes*.
At 04:34 PM 7/16/2003 -0400, Bill Strahm wrote:
Why, oh WHY would I want to receive a known corrupted packet ?
usually it is something about it taking multiple seconds for data to arrive with a very high BER, and including FEC in the application data that would allow the system to recover enough useful information to make it worthwhile. Think interplanetary space. There is also discussion of 64K MTUs in some sectors, which I tend to think is misguided (I understand reasons for larger packets, or at least I think I do, but I think the trade-offs don't justify them).