This is great. It will really come in handy on my 3rd try at the CCIE (350-001) test. Thanks again, [EMAIL PROTECTED] wrote: > Mike, > > Jumping in on the back of Nigel's reply: > > Canonical to Non-canonical MAC address Conversion > > Break down MAC address into nibbles, (half a byte, or 4 bits) > > Convert HEX digit to binary: > > 0 = 0000 , 1 = 0001 > 2 = 0010 , 3 = 0011 > 4 = 0100 , 5 = 0101 > 6 = 0110 , 7 = 0111 > 8 = 1000 , 9 = 1001 > A = 1010 , B = 1011 > C = 1100 , D = 1101 > E = 1110 , F = 1111 > > Then reverse the pattern of bits for each nibble: > > 0000 = 0000 , 0001 = 1000 > 0010 = 0100 , 0011 = 1100 > 0100 = 0010 , 0101 = 1010 > 0110 = 0110 , 0111 = 1110 > 1000 = 0001 , 1001 = 1001 > 1010 = 0101 , 1011 = 1101 > 1100 = 0011 , 1101 = 1011 > 1110 = 0111 , 1111 = 1111 > > The convert back to HEX: > > 0000 = 0 , 1000 = 8 > 0100 = 4 , 1100 = C > 0010 = 2 , 1010 = A > 0110 = 6 , 1110 = E > 0001 = 1 , 1001 = 9 > 0101 = 5 , 1101 = D > 0011 = 3 , 1011 = B > 0111 = 7 , 1111 = F > > Then swap the resulting nibbles (1 with 2, 3 with 4 etc.) to > reverse each byte, > > Do this for all 6 pairs of nibbles, and there you have it! > > Here's a simpler table to follow, but it's best > to be able to learn how to do it from scratch, I suspect. > > 0 - 0 > 1 - 8 > 2 - 4 > 3 - C > 4 - 2 > 5 - A > 6 - 6 > 7 - E > 8 - 1 > 9 - 9 > A - 5 > B - D > C - 3 > D - B > E - 7 > F - F > > An example or two might help: > > Token Ring Address: > 40-00-37-46-00-01 > Break it down into nibbles: > 4 - 0 - 0 - 0 - 3 - 7 - 4 - 6 - 0 - 0 - 0 - 1 > Convert them into binary: > 0100 0000 0000 0000 0011 0111 0100 0110 0000 0000 0000 0001 > Reverse the nibbles: > 0010 0000 0000 0000 1100 1110 0010 0110 0000 0000 0000 1000 > Convert back to HEX: > 2 - 0 - 0 - 0 - C - E - 2 - 6 - 0 - 0 - 0 - 8 > Swap each nibble in each pair of nibbles: > 02-00-EC-62-00-80 > > And there you have it! > > It doesn't matter if you start with Cannonical to Non-canonical, > it's the same > process each time. If you can handle converting a byte at a time > - it's a little > quicker than this, and after a while you can do it in your head. > (Just don't > tell people at parties - normal people regard this as really > sad!) > > Here's a couple of pointers on the web: > http://www.cisco.com/warp/public/698/1.html > http://www.cisco.com/warp/public/650/37.html > > More general Token Ring: > http://www.faqs.org/faqs/LANs/token-ring-faq/ > > Someone had a perl script that converted these things AFAIR that > they > mentioned looonnnnngg time ago on this list, might be worth a > trawl > of the archives. > > Hope this helps > > Regards > > Pete S. > > --- Original Message --- > "Nigel Taylor" <[EMAIL PROTECTED]> Wrote on > Fri, 1 Dec 2000 02:57:48 -0000 > ------------------ > Mike, > When I was trying to get a grasp on this topic I > had some > questions a some different areas but found the White paper on > CertificationZone to make all the difference. Both the Token > ring and the > Bridging really help me grasp the topic. Of course you'll need > a > subscription to view it now. I know http://www.ccprep.com/ > has some whitepapers available on there site maybe there's something > there > that can shed some light on this subject for you... > > HTH > > Nigel.. > > ----- Original Message ----- > From: Mike Neal <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Thursday, November 30, 2000 5:05 PM > Subject: Token Ring Bit Swapping > > > Can anyone help me with Bit swapping from Token to Ethernet. > > I can't seem to grasp how it is done. > > > > Thanks, > > Mike > > > > _________________________________ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > ----- > Sent using MailStart.com ( http://MailStart.Com/welcome.html ) > The FREE way to access your mailbox via any web browser, anywhere!
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