From: Venkatesh Palani (kvpalani@gmail.com)
Date: Sat Dec 24 2005 - 05:53:37 GMT-3
Thanks Brian and scott , definietly one more tip to improve my speed.
Thank you guys :-)
On 12/24/05, Brian McGahan <bmcgahan@internetworkexpert.com> wrote:
>
> Venkatesh,
>
> You are still doing the same binary logic whether you say 17 is
> "16+1" or 10001. Also it's much faster just to use Windows calculator to
> convert 214 into 11010110 than it is to convert it to 128+64+16+4+2 in your
> head.
>
> Brian McGahan, CCIE #8593
> bmcgahan@internetworkexpert.com
>
> Internetwork Expert, Inc.
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> ________________________________________
> From: Venkatesh Palani [mailto:kvpalani@gmail.com]
> Sent: Friday, December 23, 2005 1:35 AM
> To: swm@emanon.com
> Cc: Farrukh Haroon; Khurana, Sameer; Emil Patel; Nawaz, Ajaz; nenad pudar;
> Brian McGahan; ccielab@groupstudy.com
> Subject: Re: Question for Brian McGahan and others
>
> HI Scot,
> Thanks for your insight explanation, but I am afraid If I have not
> explained it in theright way.
>
> My concept is
>
> the same digits will form the network part
> and the rest will be taken to for the maskpart (not the common ones)
>
> so I am not using the same digits to form the masks this goes with ur XOR
> logic.
>
> let me try again
>
> [8+2].[16+4+].[16+4+8++2].[32+8] ----> 1
> [32+8].[16+4+8+2].[16+4].[8+2] ------> 2
>
> I am taking the common stuff form 1 and 2 to formthe networkpart not for
> the mask
> so in this case
>
> it will be 8.[16+4].[16+4].8
>
>
> and the left overs are the remaiing stuffs are used for the mask in this
> it can be translated as non identical ones
>
> so it will be
>
> [32+2].[8+2].[8+2].[32+2]
>
> which is 34.10.10.34 and I do accept this is not a perfect match though my
> intention was to use a single ACL. My appologies for not mentioning it
> directly but I refrenced IE in previous mail actually what I was
> refrencingwas http://www.internetworkexpert.com/resources/01700370.htm.
>
>
>
>
>
> Thank you,
>
>
>
>
>
>
> On 12/23/05, Scott Morris <swm@emanon.com> wrote:
> So you're saying the mask would be 8.20.20.8???
>
> First, that's mathematically incorrect but we'll worry about that in a
> moment.
> Second, look at the mask in binary:
>
> 00001000.00010100.00010100.00001000...There are 6 one-bits in there.2^6
> = 64 matches to that mask alone.You only listed two things to match.
>
> If you are FORCED to come up with a one-line ACL that may be acceptable,
> otherwise I would advise against it.If you don't care how many extra
> things you're permitting or denying just use "any any" to save the brain
> power.
>
> So on the math side, I think you're looking at it wrong for what bits go
> where.If your two values have a bit in common you do NOT put a one-bit in
> the mask.The XOR would be 0.So your 8-bit-position value, since they
> both have it would yeild a 0 in that position whereas the 32 and 4 bit
> positions would have a 1 in the mask.
>
> So to get them in one line:
>
> 00100010.00001010.00001010.00100010 which is worse because it gives 8 bits
> of 1's in the mask and 2^8 = 256 matches.
>
> 34.10.10.34 would be your mask if your were FORCED to come up with a
> one-line ACL.IMHO this is rare and not incredibly bright.If your lab
> tells you to do it, well...Just do it. ;)
>
> Scott
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Venkatesh Palani
> Sent: Thursday, December 22, 2005 9:28 PM
> To: Scott Morris
> Cc: Farrukh Haroon; Khurana, Sameer; Emil Patel; Nawaz, Ajaz; nenad pudar;
> bmcgahan@internetworkexpert.com; ccielab@groupstudy.com
> Subject: Re: Question for Brian McGahan and others
>
> sorry I just realized there is a TYPO
>
>
> vlaue for 30 is 16+8+4+2 and not 16+4+2.
>
>
> ThanX
>
>
> On 12/23/05, Venkatesh Palani < kvpalani@gmail.com> wrote:
> >
> >
> > Hi All,
> >
> > Thanks Scott, I personllay dont use binary rather I use Decimal.
> >
> > below is the technique
> >
> > for instance lets take the same example from IE
> >
> > 10.20.30.40
> > 40.30.20.10
> >
> > to find a access list for these address with overlapping networks I
> > wld write the aboves address as shown below
> >
> > [8+2].[16+4].[16+4+2].[32+8]
> > [32+8].[16+4+2].[16+4].[8+2]
> >
> > and the common vlaues in two colums shld represent the network
> > address and the remaining shld fall back as wild cad mask
> >
> >
> > in this case it will be
> >
> > 8.[16+4].[16+4].[8]= 8.20.20.8
> >
> > and the wild card mask is the sum of the left overs(the vlaues that
> > were not used in the network address) in each octects from all the
> > rows(in this case only two rows)
> >
> > [32+2].[8+2].[8+2].[32+2] = 34.10.10.34
> >
> >
> > This shld work for any no of rows , this works better for me rather
> > than those AND and XOR operations. Any comments are welcome.
> >
> >
> > Thanx,
> >
> > Venkatesh
> >
> >
> >On 12/23/05, Scott Morris <swm@emanon.com > wrote:
> > >
> > > From: http://en.wikipedia.org/wiki/Xor
> > >
> > > The case of a three, or more, input XOR operation tends to be an
> > > ill-considered case. An XOR operation with three simultaneous inputs
> > > is not so easily expressed in most popular programming languages.
> > > When expressed as successive binary operations the result is a
> > > simple parity, giving a TRUE result for any odd number of TRUE
> > > inputs.
> > > three ones XORed simultaneously
> > >
> > > When taken as a multi-input black box whose operation follows the
> > > formal
> > >
> > > definition and yields the result TRUE when one, and only one, of its
> > > inputs is TRUE, the behaviour is inconsistent with the successive
> > > binary mode.
> > > For
> > > example; in the case where three inputs are all TRUE (as shown on
> > > the right, in the IEC symbology to emphasise the definition) the
> > > result would have to be FALSE because it does not meet the condition
> > > that "only one of its inputs is TRUE".
> > > [edit]
> > >
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto: nobody@groupstudy.com] On
> > > Behalf Of Farrukh Haroon
> > > Sent: Thursday, December 22, 2005 3:54 PM
> > > To: Khurana, Sameer
> > > Cc: Emil Patel; Nawaz, Ajaz; nenad pudar;
> > > bmcgahan@internetworkexpert.com; ccielab@groupstudy.com
> > > Subject: Re: Question for Brian McGahan and others
> > >
> > > what happened to the definition of XOR I learnt in college....
> > >
> > > Odd Number of 1's in input Results in Output of 1,Output = 0
> > > otherwise...
> > >
> > > ??
> > >
> > > On 12/22/05, Khurana, Sameer < SKHURANA@amfam.com> wrote:
> > > >
> > > > I think you meant by column ;)
> > > >
> > > > Concept remains the same if its 4 rows, 5 rows or 10 rows.
> > > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [mailto: nobody@groupstudy.com] On
> > > > Behalf Of Emil Patel
> > > > Sent: Thursday, December 22, 2005 11:37 AM
> > > > To: 'Nawaz, Ajaz'; 'nenad pudar'; bmcgahan@internetworkexpert.com
> > > > ; ccielab@groupstudy.com
> > > > Subject: RE: Question for Brian McGahan and others
> > > >
> > > >
> > > > If the row is dissimilar the end result is 1.
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [mailto: nobody@groupstudy.com] On
> > > > Behalf Of Nawaz, Ajaz
> > > > Sent: Thursday, December 22, 2005 11:05 AM
> > > > To: 'Emil Patel'; 'nenad pudar'; bmcgahan@internetworkexpert.com;
> > > > ccielab@groupstudy.com
> > > > Subject: RE: Question for Brian McGahan and others
> > > >
> > > > What happens when you increase the #vertical rows and apply
> > > > various combinations of 1's and 0's.
> > > >
> > > > Let's try 5rows?
> > > >
> > > > Tia
> > > > Ajaz Nawaz
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [mailto: nobody@groupstudy.com ] On
> > > > Behalf Of Emil Patel
> > > > Sent: 22 December 2005 17:07
> > > > To: 'nenad pudar'; bmcgahan@internetworkexpert.com;
> > > > ccielab@groupstudy.com
> > > > Subject: RE: Question for Brian McGahan and others
> > > >
> > > > In XOR , if bit in a column is dissimilar result is 1. You do not
> > > > add bit row by row.
> > > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [mailto: nobody@groupstudy.com] On
> > > > Behalf Of Emil Patel
> > > > Sent: Thursday, December 22, 2005 10:49 AM
> > > > To: 'nenad pudar'; bmcgahan@internetworkexpert.com ;
> > > > ccielab@groupstudy.com
> > > > Subject: RE: Question for Brian McGahan and others
> > > >
> > > > 128 6432168 4 2 1
> > > >
> > > > 0 0 0 0 0 0 0 0
> > > > 0 0 0 0 0 1 0 0
> > > > 0 0 1 0 0 0 0 0
> > > > 0 0 1 0 0 1 0 0
> > > > ___________________________________________
> > > > 0 0 1 0 0 1 0 0 = 36
> > > >
> > > > All vertical bits are checked XOR and if they are:
> > > > (0+0)=0
> > > > (0+1)=1
> > > > (1+1)=0
> > > > (1+0)=1
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: nobody@groupstudy.com [mailto: nobody@groupstudy.com ] On
> > > > Behalf Of nenad pudar
> > > > Sent: Wednesday, December 21, 2005 7:57 PM
> > > > To: bmcgahan@internetworkexpert.com; ccielab@groupstudy.com
> > > > Subject: Question for Brian McGahan and others
> > > >
> > > > Hi Brian
> > > > I have the question regarding your paper on Computing Access-List
> > > > and Wildcard Pairs
> > > >
> > > > There you have
> > > >
> > > > 00000000
> > > > 00000100
> > > > 00100000
> > > > 00100100
> > > > _________
> > > > XOR
> > > > 00100100=36****
> > > >
> > > > I cannot get this trying in any way (for third column)
> > > >
> > > > 1) (((0 XOR 0) XOR 1) XOR 1)= ((0 XOR 1) XOR 1)= 1 XOR 1 =0
> > > >
> > > > 2) (0 XOR 0) XOR (1 XOR 1) = 0 XOR 0 = 0
> > > >
> > > > I am doing something wrong or there is some other trick here ?
> > > >
> > > >
> > > > thanks
> > > > nenad
> > > >
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