The binary method is nice because it is what the router does. In addition, in the process, you get out a lot more information. For instance, you can quickly determine the class without having to memorize all of the ranges with the following binary patterns: Class A: 0 [0-127] Class B: 10 [128-191] Class C: 110 [192-223] Class D: 1110 [224-239] Class E: 1111 [240-255] Not to mention, as you run the bits you can see exactly what is happening. Granted, there are still tricks. For instance, the following table helps calculate things quickly: 128 64 32 16 8 4 2 1 128 192 224 240 248 252 254 255 Notice that it's just the bit values across the top, and the sum of the bit values across the bottom. So if you write that out, you can find out exactly what your masks are and the bit patterns that go with them without any "tricks". Mike Priscilla Oppenheimer wrote: > 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 . >>. . >> >>Deb >> >>""John Neiberger"" wrote in message >>[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... >>| I disagree wholeheartedly with one of those statements. In this >>| business you never really "arrive" in the first place, so the journey >>| itself is as important or more important than the destination. You >>| learn binary subnetting techniques for the same reason students learn >>| math without calculators. It's important that you really understand what >>| is occurring if you want to be a good engineer. >>| >>| Liken this situation to cars. If you just want to use the tools >>| without understanding, then you are a driver only. If you want to be a >>| mechanic and know what's happening under the hood, then you have to >>| learn the stuff the hard way. >>| >>| Back to reality for a bit. As far as subnetting is concerned, it's >>| very difficult to understand what's happening without learning it in >>| binary. Once you've learned it, though, it's not really necessary to do >>| it in binary because you'll have plenty of shortcuts in your head that >>| bypass--yet still rely on--the binary math you learned previously. >>| >>| Just my $.02... >>| >>| John >>| >>| >>> "Ken" 8/8/01 10:29:45 AM >>> >>| This is a study group so I have a question for which I need some >>| education. >>| I am not looking for a flame war, just education. The question I have >>| is of >>| what use is the binary math method of subnetting as compared to just >>| using a >>| program that does subnetting? If the point to the exercise is to >>| produce a >>| plan for subnetting that can then be entered into each device on the >>| network >>| or into a DHCP server setup, what else is achieved by doing this >>| manually? >>| It seems to me that the point is not the journey, but the arrival at >>| the >>| destination. Indeed arrival as quickly as possible, with the least >>| source of >>| error. As Cisco even says; "The purpose of this tool is to provide a >>| way to >>| calculate IP subnetting which is fast, easy, and error free. Doing >>| such >>| calculations manually is time consuming and susceptible to common >>| mathematical mistakes, especially in conversions between binary and >>| decimal >>| numbers." So what is it I am not understanding? >>| >>| >>| >>| >>| >> > ________________________ > > Priscilla Oppenheimer > http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=15354&t=15354 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
