The best way for me to understand is to do the binary, and let the shortcuts go hang. As someone once said to me "I'm not smart enough to do the shortcuts"
Kage Roc wrote: > > I promise I will not be a knowledge leech, I will contribute > what I know as well. Ofcourse I do have a question regarding > IP Summaization: Up untill today I thought I had > summarization down cold until I tried a few self made > excercises. The formula I used to gather a summ address was > 2n=x. Thats 2 to the n power equals x. > x is the number of subnets that you want to summarize and n > will be how much you subtract from the lowest mask of those > subnets. for example: > > > 216.52.146.136/30 > 216.52.146.140/30 > 216.52.146.144/30 > 216.52.146.148/30 you can only summarize to where the bits are identical. Looking at the last octet: 136=10001000 140=10001100 144=10010000 148=10010100 the boundary would be at /27, the total of the first three octets and the 3 bits of the fourth. The summary route would be 216.52.146.128/27 If you use /28 for those networks, you're gonna get something funky. > > using that formula the summ would be 216.52.146.136/28 which is > not a valid route. Hoever that formula works here: > 216.52.146.48/29 > 216.52.146.56/29 > > summ route: 216.52.146.48 /28 > here the last octets are: 48=00110000 56=00111000 making the masked bits /28 (3 octets + 4 identical bits) > I guess my question is, what is the best/effective/convient way > to derive summary addresses? Thanks for any input. > If you're very lucky, you have the brain to do this silliness in your head. Otherwise, just do the binary conversions and draw lines. --Tim, the pretty sure he got that right. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=42241&t=41998 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
