Cisco CCNA (200-301)Network FundamentalsMedium
A switch has 24 hosts connected to 24 separate access ports, all assigned to the same VLAN. How many collision domains and broadcast domains exist on this switch?
- A1 collision domain and 1 broadcast domain
- B24 collision domains and 1 broadcast domain
- C1 collision domain and 24 broadcast domains
- D24 collision domains and 24 broadcast domains
Show answer & explanationAnswer & explanation
Correct answer: B. 24 collision domains and 1 broadcast domain
Each switch port is its own collision domain because switches use full-duplex, dedicated links per port. However, since all 24 hosts are in the same VLAN, they share a single broadcast domain because broadcasts are flooded to all ports within that VLAN.
Why the other options are wrong
- A. Switch ports each form their own collision domain, so this undercounts collision domains.
- C. This reverses the correct relationship between collision and broadcast domains on a switch.
- D. Broadcast domains are not per-port on a switch; they are per-VLAN.
Collision vs Broadcast Domain (Switch)
On a switch, each port is a separate collision domain, but all ports in the same VLAN share one broadcast domain.
- Switches eliminate collisions per port via full duplex
- VLANs define broadcast domain boundaries
- Routers are needed to separate broadcast domains between VLANs
Memory trick: 'Every port collides alone, but VLANs shout together.'