Collision and broadcast domains — Aptitude Question
Collision and broadcast domains: A single 24-port Ethernet switch has one host on each port and no VLANs configured. Answer and worked solution on CodeKairo.
- Topic: OS, DBMS & Networks
- Section: Programming MCQs
- Difficulty: Medium
- Time target: 90 seconds
Question
A single 24-port Ethernet switch has one host on each port and no VLANs configured. How many collision domains and broadcast domains exist?
Options
- 1 collision domain and 1 broadcast domain
- 1 collision domain and 24 broadcast domains
- 24 collision domains and 1 broadcast domain
- 24 collision domains and 24 broadcast domains
Show the answer and the worked solution
Correct answer: C. 24 collision domains and 1 broadcast domain
Worked solution
- A switch gives every port its own segment, so a collision on one port cannot affect another: 24 ports mean 24 collision domains.
- A switch floods a broadcast frame out of every other port, so all 24 hosts hear one another's broadcasts and form one broadcast domain.
- So there are 24 collision domains and 1 broadcast domain; splitting the broadcast domain would need VLANs or a router.
Answer: 24 collision domains and 1 broadcast domain.
The idea
A switch breaks collision domains, a router breaks broadcast domains, and a hub breaks neither. Those three sentences answer every question in this family.
Shortcut. A switch gives each port its own collision domain (24) and floods broadcasts everywhere, so only a router or VLAN would split the single broadcast domain.
Common trap. "1 collision domain and 1 broadcast domain" is the answer for a hub, which shares one medium among all its ports.