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I agree with what you have stated and I understand. However this is not an XOR.
Brian
—–Original Message—– From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Ricardo AF Silva Sent: Friday, July 28, 2006 10:53 AM To: Brian Cc: ccielab@groupstudy.com Subject: Re: XOR for Computing ACL Masks
Brian, I think I got your point so,
Given two inputs A & B, Xor’ed, the output Y is:
A B Y 0 0 0 0 1 1 1 0 1 1 1 0
For three inputs A, B and C, the output Y is:
A B C Y 0 0 0 0 0 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1 0
Conclusion: the inputs are different ( no matter how many inputs) Y is 1) the inputs are the same, Y is 0… That is the logic behind XOR… Look at the inputs and just check if are equal or not….
HTH Ricardo
As you can see in the example you have On Friday 28 July 2006 13:17, Brian wrote: > I was using http://mathworld.wolfram.com/XOR.html as a reference. I am > interested in the specific process (steps) that were used in the > example. > > Brian > > —–Original Message—– > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of > Mienbaikebi Patani > Sent: Friday, July 28, 2006 9:00 AM > To: Brian > Cc: ccielab@groupstudy.com > Subject: Re: XOR for Computing ACL Masks > > I think the XOR works such that u need to have equal number of 0 and 1 > for > the result to be equal to 1. Anything other than equal number of 0 and 1 > results in a value equal to 0. > > Hope that was informative brother. > > On 7/28/06, Brian wrote: > > I have been looking at the following example on how to calculate an > > appropriate mask. > > http://www.internetworkexpert.com/resources/01700370.htm. While I > > understand the process that was use (and it works well) I cannot > > figure > > > out how the mask was calculated using XOR in example 2. If I > > understand > > > XOR correctly anytime there are an even number of 1’s in a computation > > the result of XOR will be 0. When there are an odd number of 1’s the > > result will be 1. This does not seem to hold true in the example. > > > > Can someone please help me understand how XOR was applied to come up > > with the mask in example 2. Specifically the second octet is where > > the > > > confusion comes in. The only conclusions I can draw are that this is > > not truly an XOR or I do not understand XOR. > > > > By the way I tried to XOR 0011 in the MS calculator and the result is > > 0. > > > Thanks! > >