thanks for the excellant notes! cheers! suresh CNE,MCSE+I,CLS,SCSA,CCNA,CCNP,MCNS,CCIE(Write) http://www.sureshhomepage.com
>From: "John Neiberger" >Reply-To: "John Neiberger" >To: [EMAIL PROTECTED] >Subject: How to Summarize Network Addresses [7:29149] >Date: Thu, 13 Dec 2001 17:40:08 -0500 > >Someone just asked me off-list how to summarize a certain range of >addresses and I thought it might be helpful to post my reply to the >list. It seems like everybody has their own shortcut to doing this, but >this is how I learned how to do it. Once you learn it there are plenty >of shortcuts. > > > >As far as summarization goes, to really understand what you're doing >you need to think in binary. Write out those addresses in binary >first: > >00001010.00000001.00000001.00000000 = 10.1.1.0/24 >00001010.00000001.00000011.00000000 = 10.1.3.0/24 >00001010.00000001.00001110.01000000 = 10.1.14.64/26 > >You can see that in binary they are all the same up to the 20th bit. >If you slice the above table into two pieces at the 20th bit, on the >left side you are left with: > >00001010.00000001.0000 > >This, translated back to decimal, is 10.1.0.0/20, which is your >summarized address. However, this is an awful example. Those would be >really bad addresses to try to summarize. A better example would be >this: > >10.1.0.0/24 >10.1.1.0/24 >10.1.2.0/24 >10.1.3.0/24 > >00001010.00000001.00000000.00000000 >00001010.00000001.00000001.00000000 >00001010.00000001.00000010.00000000 >00001010.00000001.00000011.00000000 > >You can see that these are the same up to the 22nd bit. Slice the >diagram into to pieces at the 22nd bit and on the left side you are left >with: > >00001010.00000001.000000 > >which translates back to decimal as 10.1.0.0/22. Now you can see that >a /22 precisely summarizes four /24s !! Cool, huh? > > > >Regards, >John _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=30013&t=29149 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
