help me how to subnet class A, B & C

well durk21 sorry then, you understood the point from the begining itself then...then why you did not tell at that time itself.

is there any other difference between VLSM and classful subnetting??

i stated that it didn't work with vlsm from nearly the beginning and multiple times in my postings

well durk21!!
thanks, atleast i got a new name for my concept!!

AND....................that is?

VLSM

Hi Ashok

VLSM is nothing but Variable length Subnet Mask. Which is used to preserv the IP wastage.... say If you need only 10 usable IP for your network...but if you use the IP 192.168.1.0/24 it gives 255 IPs, so the remaining 245 IP are unused...right..?

If you split the IP block with appropriate subnet mask (VLSM / CIDR) you can breakup the subnet blocks.

For the above example...you may use the Subnet mask as 255.255.255.240...it will give you 14 usable host IPs. So here you are wasting only 4 IPs...compare to using the default subnet mask...

Hope it may give some hint for you abt VLSM