Re: [44net] On the Issue of Subnets

Hello, It is one thing I don't really get about this rollover... A subnet is supposed to be a broadcast domain, so every subnet, don't matter how small needs a network and a broadcast address to work properly. In the classic routing schemes that means that by subnetting e.g. a /24 subnet into 4 /22 subnets you loose theoretically 2 subnets, and can use only x.x.x.64/22 and x.x.x./128/22. And this means also that only subnetting in steps of 2 is possible (and also /31 is not a valid subnetting scheme). Classless approaches eliminate this and allow the use of all subnets created by subnetting (and I think all modern routers and OSes support this). But you still have to reserve (IP & Mask) for the network address and (IP | (~mask)) for the broadcast address (e.g. 44.x.x.0 and 44.x.x.255 on a /24 subnet). This means that the roll over on the subnet boundary would have to be e.g. 44.x.x.254 -> 44.x.x+1.1 or the routers on the subnet gateway may go havoc. Correct me if I'm wrong... Marius, YO2LOJ -----Original Message----- From: 44net-bounces+marius=yo2loj.ro(a)hamradio.ucsd.edu [mailto:44net-bounces+marius=yo2loj.ro@hamradio.ucsd.edu] On Behalf Of Geoff Joy Sent: Saturday, February 25, 2012 08:29 To: AMPRNet working group Subject: Re: [44net] On the Issue of Subnets On Thu, 23 Feb 2012 17:56:42 -0800, Geoff Joy <geoff(a)windowmeister.com> wrote: Correction: Subnet 16 rolls over into subnet 17. 2 00101100.00010010.00010000.11111111 44.18.16.0/24 34 00101100.00010010.00010001.00000000 44.18.17.0/24 _________________________________________ 44Net mailing list 44Net(a)hamradio.ucsd.edu http://hamradio.ucsd.edu/mailman/listinfo/44net