220-1101 Networking Practice Question
A small office has 18 computers that need to be connected to share files and access the internet. The ISP provides a modem with a single Ethernet port. The office router has four LAN ports. Which device should the technician add to enable all 18 computers to connect to the network?
⚠ Common exam trap
Candidates often confuse a hub with a switch, assuming both simply 'split' a connection, but a hub creates a single collision domain and half-duplex operation, while a switch provides full-duplex, dedicated bandwidth per port.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
B. A switch
A switch is the correct device because it provides multiple Ethernet ports (typically 24 or 48) and operates at Layer 2, forwarding frames based on MAC addresses. This allows all 18 computers to connect to the network, share files, and access the internet through the existing router, which only has four LAN ports.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A. A hub
Why it's wrong here
A hub is an older device that repeats data to all ports, causing collisions and inefficient use of bandwidth. While it could physically connect the computers, it would degrade performance and is not recommended for modern networks.
- ✓
B. A switch
Why this is correct
A switch operates at Layer 2 of the OSI model, using MAC addresses to forward frames only to the specific port where the destination device is connected. Unlike a hub, it creates a dedicated collision domain per port, allowing simultaneous full-duplex communications. This makes it ideal for connecting 18 computers, as it provides multiple ports and manages traffic efficiently without unnecessary broadcasting.
- ✗
C. A bridge
Why it's wrong here
A bridge typically has two ports and is used to connect two separate network segments, filtering traffic based on MAC addresses. It does not provide a high-density port count needed to connect 18 individual computers directly. While it can segment a network to reduce collision domains, it is not a multi-port connectivity solution like a switch.
- ✗
D. A firewall
Why it's wrong here
A firewall is a security appliance that filters traffic based on predetermined rules, inspecting packets and blocking malicious activity. It operates primarily at layers 3 and 4 (or even application layer) and is not designed to function as a network expansion device. While it may have multiple network interfaces, its purpose is security enforcement, not providing a switched fabric for client connectivity.
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1101 exam.