ICND1 2.0: Address Blocks and VLSM

Interconnecting Cisco Network Devices Part 1 is essential for students preparing for the CCNA Routing and Switching or CCENT certifications. Students pursuing the CCNA Routing and Switching certification should complete parts 1 & 2 of the ICND learning path. Students pursuing the CCENT certification need only attend part 1 of the ICND curriculum.Anyone wishing to obtain Cisco Certified Network Associate (CCNA) 100-101 certification that validates the knowledge and skills required to successfully install, operate, and troubleshoot small to medium size enterprise branch network. Network administrators, network engineers, network managers, network designers, and project managers. Familiarity of navigating PC operating systems, the Internet, and basic IP addressing knowledge skills recommended.

Please contact us for information about prerequisites.

Expected Duration
90 minutes

Once you have the subnetting basics down and understand how to divide a network into two or more networks you are ready to determine the optimal subnet mask for a given scenario and how to calculate the usable range of IP addresses that can be used in each of those subnets. This course starts by reviewing and working through a detailed subnetting example that has specific requirements.
Next the course introduces block sizes which tell you how many addresses are within the network. It also explains how the first subnet address is reserved to refer to the network itself and the last address is reserved as the broadcast address, so that within any given netblock two less usable addresses are unavailable for use. Finding the block size is covered using two methods.
VLSM lets you allocate IP addresses more efficiently by adding multiple layers to the addressing hierarchy. This course concludes by describing the role of VLSM and how to use VLSM options to allocate more than one subnet mask within a network and to subnet an already subnetted network address.


Address Blocks

  • determine the subnets that will be produced in a given scenario
  • identify the usable range of addresses within a subnet
  • given an example, determine the block size of a subnet
  • determine the subnet ID, broadcast address, and usable address range of a given subnet
  • identify the considerations involved in addressing a broadcast domain
  • given an address from class A, B, or C, determine the network ID, directed broadcast, and first and last hosts

Variable Length Subnet Masks (VLSM)

  • recognize the benefits of Variable Length Subnet Masking
  • identify the best way to gain a specific number of hosts





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