Calculating IPv4 Subnets and Host

VLSM (Variable length Subnet Masks)
  • Class-based networks are inefficient
    • The subnet mask is based on the network class
  • Allow network administrators to define their own masks
    • Customize the subnet mask to specific network requirements
  • Use different subnet masks in the same classful network
    • 10.0.0.0/8 is the class A network - 10.0.1.0/24 and 10.0.8.0/26 would be VLSM
Number of subnets = 2 subnet bits Hosts per subnet = 2 host bits - 2

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