Collision vs broadcast domains: Which statement about what a switch and a router create is true in a default, non-VLAN Ethernet LAN?

Introduction / Context:
Designing Ethernet LANs requires distinguishing how switches and routers segment traffic. Switches break up collisions; routers break up broadcasts. This determines scalability and performance.

Given Data / Assumptions:

• No VLANs are configured; one VLAN, one broadcast domain across the switch.
• Switch ports operate as individual collision domains.
• Routers separate broadcast domains at Layer 3.

Concept / Approach:
Each switch port is its own collision domain; hence, a switch creates many collision domains but still one broadcast domain per VLAN. A router does not forward broadcasts between interfaces, thereby creating distinct broadcast domains on each interface/subnet.

Step-by-Step Solution:

Verification / Alternative check:
Simple lab: ARP broadcast will traverse all switch ports in a VLAN, but not pass through the router to another subnet.

Why Other Options Are Wrong:
Options claiming a switch creates multiple broadcast domains are wrong without VLANs. Options claiming a router creates only collision domains misunderstand L3 behavior.

Common Pitfalls:
Equating switch segmentation with broadcast segmentation; only VLANs or routers segment broadcasts.

Final Answer:
A switch creates separate collision domains but one broadcast domain. A router provides a separate broadcast domain.