Summary addressing [7:41998]
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 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 I guess my question is, what is the best/effective/convient way to derive summary addresses? Thanks for any input. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=41998&t=41998 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: Summary addressing [7:41998]
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=1001 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 216.52.146.136/28which 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=0011 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]
Re: Summary addressing [7:41998]
Agreed! Mike W. "timothy thielen" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > 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=1001 > 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=0011 > 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=42246&t=41998 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Summary addressing [7:41998]
I'm wondering whether it's worth me trying to explain my thought process after 6 pints of cider. But the six pints say YES - have a go. I'm too lazy to do the binary. You've got to get used to the size of blocks involved with each mask. By that, I mean a /30 immediately suggests blocks of four. A /29 blocks of eight etc. You had four blocks of four (/30), so if they can be summarised in one statement it will have to be a block of 16, which should immediately suggest a /28. But!!! The blocks of 16 will be at 0, 16, 32..128, 144, 160... This doesn't fit your group, so you're going to need more than one statement. With your second example Your /29 suggests blocks of 8. You have two blocks of 8, so IF it's going to fit, it will be a block of 16, which is a /28. The blocks will be 0, 16, 32, 48, 64.. and your two blocks fit fine in to the above (between 48 and 64), so the summary address is 216.52.146.48 /28 Sorry if this is nonsense to some, but this is my thought process. I am not capable of doing the binary in my head. This process becomes so simple once you grasp it, and can be done in seconds for almost any summary address. It doesn't take any special brain, because I'd be out of the running, it's just hard to explain and grasp initally. Please let me know if I should give up now and go to bed. Until then, the fridge (or cooler if you like) beckons. Cheers, Gaz ""Kage Roc"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > 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 > > 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 > > I guess my question is, what is the best/effective/convient way to derive > summary addresses? Thanks for any input. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=42268&t=41998 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Summary addressing [7:41998]
Although, as I mentioned before, I think understanding the binary simplifies things. But I agree with your pints! If it works for you, do what you gotta do =) Mike W. "Gaz" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I'm wondering whether it's worth me trying to explain my thought process > after 6 pints of cider. But the six pints say YES - have a go. > I'm too lazy to do the binary. > > You've got to get used to the size of blocks involved with each mask. By > that, I mean a /30 immediately suggests blocks of four. A /29 blocks of > eight etc. > > You had four blocks of four (/30), so if they can be summarised in one > statement it will have to be a block of 16, which should immediately suggest > a /28. > > But!!! The blocks of 16 will be at 0, 16, 32..128, 144, 160... > > This doesn't fit your group, so you're going to need more than one > statement. > > > With your second example > > Your /29 suggests blocks of 8. You have two blocks of 8, so IF it's going to > fit, it will be a block of 16, which is a /28. > > The blocks will be 0, 16, 32, 48, 64.. > > and your two blocks fit fine in to the above (between 48 and 64), so the > summary address is 216.52.146.48 /28 > > > > Sorry if this is nonsense to some, but this is my thought process. I am not > capable of doing the binary in my head. This process becomes so simple once > you grasp it, and can be done in seconds for almost any summary address. > It doesn't take any special brain, because I'd be out of the running, it's > just hard to explain and grasp initally. > > Please let me know if I should give up now and go to bed. Until then, the > fridge (or cooler if you like) beckons. > > Cheers, > > Gaz > > > > > > ""Kage Roc"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > 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 > > > > 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 > > > > I guess my question is, what is the best/effective/convient way to derive > > summary addresses? Thanks for any input. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=42290&t=41998 -- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
