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Re: Conversion canonical to non-canonical posted 04/28/2002
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If it is ethernet, and you are building filters for dlsw always convert.


As for converting, you do not need to memorize the numbers if you convert to
binary flip then swap.
I only know 1 way to convert and it is probably the same as everyone else
except I find it eaiser to flip the binary reference then trying to flip the
binary number. It just seems to be quicker and I can do it without thinking
too much. A hex number is represented  by a nibble or half a byte in binary.
Take 2 hex digits at a time, convert them to binary, flip the binary number
(or reference ) and reverse their places.

Canonical:   = 04 5a 49 88 d7

Take the first 2 numbers and convert to binary

binary reference               8421
8421
0 in binary =                      0000            4 in binary =       0100

Now we have the binary number we flip it. I find it easier to flip the
reference rather then flipping the binary number. The way I was taught of
course was to flip the binary number (not the reference as shown), but this
seems to be a waste of time, and for me is a little more difficult to do in
my head then just reversing the reference. Just count the reference
backwards.

                   1248                                        1248
0 flipped = 0000             4 flipped =         0100   or 2

 of course zero is zero in hex and 4 is 2 in hex. All we have to do is swap
places from the two numbers we took. Just swap the first and second numbers
so the non canonical equivelant of this excerise is

20

moving to the next group of two hex numbers. 5A

                    8421                8421
1248                            1248
        5 =      0101        a=   1010                 flip 'em
0101   = a hex            1010  = 5 hex

swap places     5a    we now have 205a.

                8421                8421                             1248
1248
        4 =  0100        9 =  1001        flip                 0100   =2
1001 = 9.         swap   92 now we have 205a92. 8 is relatively easy
especially since there are 2 in a row. 8 flipped of course is 1. so 11. we
have 205a9211, and lastly

            8421                8421                                    1248
1248
d=       1101         7 =  0111                    flip           1101  =b
0111 = e             swap   eb

205a9211eb





----- Original Message -----
From: "Babacar Diop" <babacard2000@xxxxxxxxx>
To: <fningham@xxxxxxx>
Cc: "cciegroup" <ccielab@xxxxxxxxxxxxxx>
Sent: Sunday, April 28, 2002 3:56 PM
Subject: Re: Conversion canonical to non-canonical


> Does anyone has a better explanation for this? I would
> really appreciate it. Also, is there an easy way to do
> the conversion or does one have to memorize how to
> convert every single digit/character?
>
> Thanks
>
>
> --- fningham@xxxxxxx wrote:
> > DLSW uses only non-canonical addresses so you would
> > need to convert whenever you have an Ethernet
> > address
> > to use in a DLSW statement.  This could be in a
> > icanreach statement, or in a MAC filter access-list.
> >
> > HTH, Fred
> > > Group,
> > >
> > > When do you need to convert from canonical to
> > > non-canonical in DLSw. Anyone as a doc on when and
> > how
> > > to do it?
> > >
> > > Thanks
> > >
> > > __________________________________________________
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