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Re: Jumbo Frames in 10GbE? (Jain's FDDI estimate of CRC max length)




At 1:41 PM 99/6/21, Ted Schroeder wrote:
>Please check the document Error Characteristics of FDDI by Raj Jain.
>
>http://www.netlab.ohio-state.edu/~jain/papers/xie1.htm
>
>The CRC-32 algorithm breaks down at 11454 octets given the error
>characteristics he analyzes in his paper.

I just read Jain's paper.  His rationale is very FDDI specific, depending
on the interaction of NRZI with the 4B/5B code used by FDDI, so one would
expect to get a much different answer for 8B/10B.  My instinct is that the
Fibre-Channel/GbE answer will be that breakdown occurs only for much larger
packets than 11,454 bytes, because there is so much more codespace in the
8B/10B code than the 4B/5B code.  The breakdown will not occur for shorter
packets.

However, as I haven't redone Jain's analysis for 8B/10B, I don't know the
new breakdown size.  It would be interesting; maybe someday.

Joe Gwinn