Difference Between Subnetmask and DBA

Question

Given a classful network if we are given an IP address . How do we deffertiate it as DBA or Subnetmask ?
Are the same ? Please explain with an example

Comments

Any specific question to explain..

Answer 1

convert to binary and see..
in subnet mask all bits in NID and SID will be all 1s and HID part will be all 0s
in DBA all bits in HID will be 1

example, for 200.1.2.0 (class C)
subnet mask will be 255.255.255.192(if suppose 2 bits are chosen for subnetting...class C means NID contains 24 bits and 8 bits as HID and from those 8 bits in HID we selected 2 bits for subnetting..so, get the subnet mask put all (24+2) bits as 1 and remaining 6 bits as 0)
and,DBA=200.1.2.255 (let us assume no subnetting is done here so we have 24 bits as NID..let it be as it is and put all 1s in remaining 8 bits of HID)