Description

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.