VLAN design benefits in enterprise switching: Which of the following are true benefits of using Virtual LANs (VLANs)? Consider the statements below and choose the correct combination: 1) They increase the size of collision domains. 2) They allow logical grouping of users by function or department. 3) They can enhance network security through segmentation. 4) They increase the size of broadcast domains while decreasing the number of collision domains. 5) They simplify day-to-day switch administration for moves, adds, and changes. 6) They increase the number of broadcast domains while decreasing the size of each broadcast domain.

Introduction / Context:
Virtual LANs (VLANs) are a foundational Layer 2 technology in enterprise networks. They let administrators logically segment traffic on the same physical switch fabric, improving manageability, performance, and security. This question tests recognition of the real, widely accepted benefits of VLANs versus common misconceptions.

Given Data / Assumptions:

• Statements 1–6 describe possible VLAN characteristics.
• We must pick the set that lists true benefits.

Concept / Approach:
VLANs create separate broadcast domains at Layer 2. By splitting one big broadcast domain into multiple smaller ones, VLANs reduce broadcast scope, allow logical user grouping, and help contain security risks. Collision domains are determined by switch ports and are not made larger by VLANs.

Step-by-Step Solution:

Verification / Alternative check:
Consider a switch with one VLAN versus three VLANs. With three VLANs, each VLAN’s broadcast traffic is contained, proving that the number of broadcast domains increases while each domain’s size decreases.

Why Other Options Are Wrong:

• 1 and 5: 1 is false; VLANs do not increase collision domain size.
• 2 and 4: 4 is false; VLANs reduce, not enlarge, broadcast domain size.
• 1, 3 and 5: 1 is false, so the combination fails.
• 2, 3, 5 and 6: Contains correct items but adds 5, which the question’s intended correct set does not include.

Common Pitfalls:
Confusing collision domains (per port) with broadcast domains (per VLAN), and assuming VLANs always simplify operations without considering configuration design.

Final Answer:
2, 3 and 6