Define Variable Length Subnet Mask and its advantage.

• A. Variable Length Subnet Mask allows subnets of different sizes within the same network to optimize address usage.
• B. It enforces uniform subnet sizes across all segments.
• C. It eliminates the need for subnetting.
• D. It increases broadcast domains.

Answer: (A)

Variable Length Subnet Masking lets you create subnets of different sizes within the same network by using different subnet masks for different subnets. The main advantage is efficient use of IP addresses: you allocate just enough addresses for each subnet, reducing waste that comes from using one fixed size for all segments. This flexibility lets you tailor each subnet to its actual needs (for example, a large department might use a /24, a small office a /28, and a point-to-point link a /30). It doesn’t enforce uniform subnet sizes, nor does it eliminate subnetting, and while more subnets can mean more broadcast domains, the defining benefit of VLSM is the optimized address usage through varying subnet sizes.