Variable Length Subnet Masking — give each area exactly the IPs it needs
What is VLSM?
Click to expand the explanation
City High School
192.168.10.0/24
The IT department at City High School was given one IP block: 192.168.10.0/24 (256 addresses). Instead of wasting IPs with equal-size subnets, they used VLSM to give each area exactly what it needs.
Address Space — 192.168.10.0/24 (256 addresses)
Student Lab (60 PCs)
Needs at least 60 usable host addresses
Staff Offices (25)
Needs at least 25 usable host addresses
Admin (10)
Needs at least 10 usable host addresses
Server Room (5)
Needs at least 5 usable host addresses
Router Link (2)
Needs at least 2 usable host addresses