As the volume of internet rapidly increases, the number of IPv4 addresses available is quickly declining, while transition to IPv6 is being delayed. As a interim solution, Variable-Length Subnet Masking(VLSM) addressing scheme, which varies the length of each IP address allowing more efficient, is being used. This paper suggests effective example of network based on virtual network with topology designed using VLSM charting rather than usual theoretical approach in VLSM, which allows more efficient use of address space.