

(EDT)
To: Randall Stewart <[email-masked]>
cc: Jonathan Wood <[email-masked]>, [email-masked],
[email-masked],
        Jim Wendt <[email-masked]>,
        Jonathan Stone <[email-masked]>,
        Craig Partridge <[email-masked]>
Subject: Re: [Tsvwg] [SCTP checksum problems] 
In-Reply-To: Your message of "Tue, 17 Apr 2001 06:30:43 CDT."
             <[email-masked]> 
Date: Tue, 17 Apr 2001 09:24:28 -0400
From: Craig Partridge <[email-masked]>
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In message <[email-masked]>, Randall Stewart writes:

>I kinda lean towards crc-32 myself (but of course I have no technical
>basis for this and need to keep silent on which one to use anyway :->),
>but do we have other candidates besides fletcher-32 and possibly
>modified 
>Adler-32 (i.e. 16 bit adds instead of 8)??

The other obvious choice is to define a TCP-32 (i.e. add in 32-bit
chunks with the carry wrapped).

>I will take the above 3 and do a bit of performance work this
>week and post some numbers... thats about all I can do i.e.  tell
>how much time the options I know of take... 

We have a fairly optimized CRC-32 running around that we can likely
send you.  I think Sklower had an optimized fletcher-32 in his paper
(though it may have only been fletcher-16 but regardless, you can
figure out how to do a faster fletcher-32 by reading his work and
much of it applies to Adler-32 as well).  Remember to test in both
endians (which is a nuisance, e.g. our CRC-32 was only done for big
endian) but it matters.

Craig

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