[c-nsp] VLSM

[Stephen J. Wilcox]

On Mon, 10 Jan 2005, Shaun wrote:

> Maybe i wasnt clear about what VLSM is or does.
> 
> It's my understanding that you usually take a /24 and carve it up into a
> number of equal subnets. (ex: /24 cut into 8 /27's).  I was asking on efnet

no, this hasnt been the case for many years since classless behaviour was 
invented in or around '92 which allowed for subnets to each have their own 
netmask rather that a single netmask applied to the whole classful network

> in #ciscohelp if it was possible to carve a /24 up into multiple CIDR's (ex:
> /29's /28's /27's etc).  They said yes and pointed me to VLSM but they did
> not recommend that i do this.

dont go back to #ciscohelp on efnet, they're either not understanding you or are 
not very good. people by default take their assignment (/20 or whatever) and 
carve them up as required, /24 is not a special size and hasnt been since 'Class 
C' ceased to have meaning 

> So my question is, if it is possble and proper can i carve a /24 up into
> diffrent CIDR's or should i stick with carving it up into equal subnets.

break it up however you wish, it will all work

Steve