What is the purpose of VLSM in IPv4 networks?

What is the purpose of VLSM in IPv4 networks?

• A. To subdivide a network into subnets of equal size.
• B. To allow subnets of different sizes within the same network to minimize address waste.
• C. To enforce that all subnets must be /24.
• D. To provide IPv6 addressing.

Answer: (B)

Variable-length subnet masking lets you assign subnet masks of different lengths to subnets within the same IPv4 network. This lets each subnet have just enough addresses for its needs, so you minimize wasted space. For example, a network might have one subdivision with about 50 hosts, another with 6 hosts, and a third with 200 hosts; you could use a /26 for the 50-host subnet, a /29 for the 6-host subnet, and a /24 for the 200-host subnet—all within the same address block. With fixed, equal-sized subnets, much more address space would be wasted or you’d have to allocate larger blocks than needed. VLSM is an IPv4 technique for efficient address use and supports flexible, scalable design; it is not about IPv6 addressing.

Variable-length subnet masking lets you assign subnet masks of different lengths to subnets within the same IPv4 network. This lets each subnet have just enough addresses for its needs, so you minimize wasted space. For example, a network might have one subdivision with about 50 hosts, another with 6 hosts, and a third with 200 hosts; you could use a /26 for the 50-host subnet, a /29 for the 6-host subnet, and a /24 for the 200-host subnet—all within the same address block. With fixed, equal-sized subnets, much more address space would be wasted or you’d have to allocate larger blocks than needed. VLSM is an IPv4 technique for efficient address use and supports flexible, scalable design; it is not about IPv6 addressing.