Re: [Rserpool] Re: Adler-32 Checksum

[Thomas Dreibholz <dreibh at iem.uni-due.de>]

On Thursday 30 June 2005 17:06, Peter Lei wrote:
> Johnson Walter-CWJ002 wrote:
> > Is there any property that makes the Internet Checksum better at
> > detecting a handlespace inconsistency as compared to a simple XOR of the
> > byte block data which is composed of the pool handle zero padded to a 32
> > bit work boundary and the 32 bit PE Id?
> >
> > Wondering since the Internet checksum will be more computationally
> > expensive.
>
> I'm not sure what your concern is here.  The Internet checksum
> is just the ones's complement of (one's complement sum + carry).
> That's two additional steps over a simple XOR sum.

XOR is computationally cheaper than addition. It works bit-wise and does not 
need a carry. So if the probability of detecting handlespace inconsistencies 
would be the same for the Internet checksum and XOR, XOR would be the 
preferable solution.


Best regards
-- 
=======================================================================
 Dipl.-Inform. Thomas Dreibholz

 University of Essen,                            Room ES210
 Inst. for Experimental Mathematics              Ellernstraße 29
 Computer Networking Technology Group            D-45326 Essen/Germany
-----------------------------------------------------------------------
 E-Mail:     dreibh at exp-math.uni-essen.de
 Homepage:   http://www.exp-math.uni-essen.de/~dreibh
=======================================================================

_______________________________________________
rserpool mailing list
rserpool at ietf.org
https://www1.ietf.org/mailman/listinfo/rserpool