classless, cidr and vlsm...

i often read people misrepresenting these three ideas, or grouping them together as if they all mean the same thing...

CIDR was created to help avoid depletion of the ipv4 space, and specifically to conserve class B addresses in the internet... CIDR is actually a grouping together of subnets, or supernetting large quantities of aggregatable addresses...

VLSM is subnetting, or the dividing up of addresses into ranges whereby overlapping is avoided and essentially, smaller, more manageable and efficient networks are created from larger ones...

Classless means the extrication of address space from classful boundaries, ie, from classful subnet masks as in /8, /16 and /24...