From: Babacar Diop (babacard2000@xxxxxxxxx)
Date: Sun Apr 28 2002 - 22:34:31 GMT-3
Thanks Chris, i figured out how to do the conversion.
I just want to make sure that i understand that
everytime i need to do filtering on ethernet, then
bit-flip the mac address given to me.
Regards,
BD
--- Chris Larson <clarson52@comcast.net> wrote:
> If by chance you want it in notepad so it comes out
> right e-mail me direct
> and I waill give you the attatchment. I think there
> is a good document on
> CCO that basically walks thru the same procedure.
>
>
>
> ----- Original Message -----
> From: "Chris Larson" <clarson52@comcast.net>
> To: "Chris Larson" <clarson52@comcast.net>; "Babacar
> Diop"
> <babacard2000@yahoo.com>; <fningham@att.net>
> Cc: "cciegroup" <ccielab@groupstudy.com>
> Sent: Sunday, April 28, 2002 9:02 PM
> Subject: Re: Conversion canonical to non-canonical
>
>
> > I guess this did not come out right so you can't
> really follow it. Sorry.
> >
> > ----- Original Message -----
> > From: "Chris Larson" <clarson52@comcast.net>
> > To: "Babacar Diop" <babacard2000@yahoo.com>;
> <fningham@att.net>
> > Cc: "cciegroup" <ccielab@groupstudy.com>
> > Sent: Sunday, April 28, 2002 6:26 PM
> > Subject: Re: Conversion canonical to non-canonical
> >
> >
> > > 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@yahoo.com>
> > > To: <fningham@att.net>
> > > Cc: "cciegroup" <ccielab@groupstudy.com>
> > > 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@att.net 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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