Here's the trick. It's great! Thanks, Leigh Anne. See one minor change below. Priscilla At 01:53 PM 8/9/01, Leigh Anne Chisholm wrote: >I can't resist a challenge! (-: > >It's actually such a wonderful tool, I can't resist trying to share the >trick... Here goes! > > > >Subnets are always created in increments of 256 minus the subnetted value. >The subnetted value is octet where the number of bits in the subnet mask are >not 0 or 255. > >IP Address: 192.168.0.0 >Subnet mask of 255.255.240.0 > ^^^ - that's our little subnetting guy. > >In this first example, subtract 256 from our subnetted value of 240 and you I think you mean subtract 240 from 256, unless we're dealing with negative numbers. ;-) >get 16. Your subnets will be in groups of 16. > > First subnet: 192.168.0.0 (Now add 16) > > Second subnet: 192.168.16.0 (Our second network - add 16 again) > > Third subnet: 192.168.32.0 (Our third network - and so on) > > 4th: 192.168.48.0 > 5th: 192.168.64.0 > 6th: 192.168.80.0 > 7th: 192.168.96.0 > 8th: 192.168.112.0 > 9th: 192.168.128.0 > 10th: 192.168.144.0 > 11th: 192.168.160.0 > 12th: 192.168.176.0 > 13th: 192.168.192.0 > 14th: 192.168.208.0 > 15th: 192.168.224.0 > 16th: 192.168.240.0 > >We borrowed 4 bits of subnetting - 2^4 = 16. And we've got 16 subnets... > > >Let's try another example. >"Subnets are always in increments of 256 minus the subnetted value." > >255.255.248.0 has subnets in blocks of 8. Using 192.168.0.0 again: > > First subnet: 192.168.0.0 (now add 8) > > Second subnet: 192.168.8.0 (Voila! Add 8 again!) > > Third subnet: 192.168.16.0 (It's just that easy!) > >etc. etc... > >-----Original Message----- >From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of >Priscilla Oppenheimer >Sent: Thursday, August 09, 2001 11:16 AM >To: [EMAIL PROTECTED] >Subject: Re: Why Should the Binary Math Method Be Used to Subnet >[7:15488] > > >I do use decimal. ;-) Just like someone else said, I do make a list such >as: 128, 192, 224, 240, 248, 252, 254, 255. > >I don't get the tricks I've seen people do where they subtract from 256 (or >something like that. Since I don't get them, I can't remember them!) > >Priscilla > > >At 11:18 AM 8/9/01, Debbie Becker wrote: > >Oh, surely not brain damaged, Priscilla! Perhaps decimally challenged? > > > > > >Deb > > > >""Priscilla Oppenheimer"" wrote in message > >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > >| Well, I have to admit to never really understanding the shortcuts that I > >| have seen people use. ;-) I guess I'm brain damaged, but I have to do it > >in > >| binary. > >| > >| As far as tools are concerned, I totally agree with the person who >pointed > >| out that in design meetings, you often don't have any tool handy except > >| your head. Sure, you may have an IP subnet calculator on your Palm, but > >the > >| client is going to look at you askance as you bury your head in the > >| itty-bitty screen, trying to use that silly stylus thing or Graffiti, > >| giving them no eye contact the whole time you're puttering with the tool. > >| Use your head and look professional and like you're worth the big bucks > >| that they are paying you. > >| > >| Priscilla > >| > >| At 03:52 PM 8/8/01, Debbie Becker wrote: > >| >I use decimal shortcuts most of the time as well -- but when I run >across > >| >something confusing, I'll go back to binary -- it always shows me the >way > >FAQ, list archives, and subscription info: > >http://www.groupstudy.com/list/cisco.html > >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=15552&t=15552 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
