Reimer, Fred wrote: > > I've always liked hex myself. A hex mask of FF.FF.F8.00 can be > written as > FFFFF800 and still mean the same thing. You obviously can't do > that with > 255.255.128.0 (255.255.128.0 != 2,552,551,280). While binary > works the same > way as hex in this manner, it is much to long for my tastes. > Plus, hex is > used a lot in programming languages when using values in > bitmasks, so I'm > more familiar with it. Also, there are only 5 hex numbers that > you need to > memorize for masks, F 0 8 C and E.
And binary is going to be pretty hard to deal with when we get to 128-bit IPv6 addresses!? Dotted decimal notation is really an awful thing. I agree with Howard that it confuses people and should be taught after the binary representation of addresses (and maybe hex?) Not only does dotted decimal notation confuse people with addresses, but it gets them thinking 8 bits at a time, when programming languages, protocol analyzers, debuggers, etc. think 4 bits at a time. Priscilla > > Fred Reimer - CCNA > > > Eclipsys Corporation, 200 Ashford Center North, Atlanta, GA > 30338 > Phone: 404-847-5177 Cell: 770-490-3071 Pager: 888-260-2050 > > > NOTICE; This email contains confidential or proprietary > information which > may be legally privileged. It is intended only for the named > recipient(s). > If an addressing or transmission error has misdirected the > email, please > notify the author by replying to this message. If you are not > the named > recipient, you are not authorized to use, disclose, distribute, > copy, print > or rely on this email, and should immediately delete it from > your computer. > > > -----Original Message----- > From: Howard C. Berkowitz [mailto:[EMAIL PROTECTED] > Sent: Tuesday, September 09, 2003 11:32 PM > To: [EMAIL PROTECTED] > Subject: RE: Please Help - CIDR - How the bits work [7:75050] > > At 10:36 PM +0000 9/9/03, Dom wrote: > >Fred, check out the archives for Howard's piece on the > difference > >between 'Rocket Science' and 'BGP' when at NASA. > > > >Best regards, > > > >Dom Stocqueler > >SysDom Technologies > >Visit our website - www.sysdom.org > > > Seriously, I've fought a battle for many years with Cisco > Training. I > believe the fundamental problem they _create_ is insisting on > teaching classful and dotted decimal notation first. > > When I've given private classes -- ICRC, the older RSC, etc. -- > I > always began discussing addressing in binary, got people used > to the > idea of prefix length, then introduced dotted decimal as a > means of > representation, and then introduced classful addressing as a > historic > concept. Students were always able to go right into classless > routing without any trouble. > > There are some nice examples in RFC 1878. RFCs 1517-1520 give > the > main background, although there are some earlier papers on > "supernetting". > > With all mercenary disclaimers, I also recommend my book, > _Designing > Addressing Architectures for Routing and Switching_, and my > recent > IPv4/IPv6 tutorial on Certification Zone. > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=75199&t=75050 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
