This N10-009 practice question tests your understanding of networking concepts. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which of the following devices operates at Layer 3 of the OSI model and makes forwarding decisions based on destination IP addresses?
Switch
Why wrong: A switch forwards frames based on MAC addresses at Layer 2, not IP addresses.
Bridge
Why wrong: A bridge also operates at Layer 2, forwarding based on MAC addresses.
Router
A router routes packets based on Layer 3 IP addresses and maintains a routing table.
Hub
Why wrong: A hub is a Layer 1 device that regenerates signals without any forwarding intelligence.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Router
A router operates at Layer 3 (Network layer) of the OSI model and uses the destination IP address in the packet header to make forwarding decisions. It maintains a routing table (e.g., via OSPF, EIGRP, or static routes) to determine the next-hop interface for each packet, enabling communication between different subnets or VLANs.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Switch
Why it's wrong here
A switch forwards frames based on MAC addresses at Layer 2, not IP addresses.
Bridge
Why it's wrong here
A bridge also operates at Layer 2, forwarding based on MAC addresses.
Router
Why this is correct
A router routes packets based on Layer 3 IP addresses and maintains a routing table.
Related concept
Read the scenario before looking for a memorised answer.
Hub
Why it's wrong here
A hub is a Layer 1 device that regenerates signals without any forwarding intelligence.
Common exam traps
The trap here is that candidates often confuse a Layer 3 switch with a router, but the question specifies a device that makes forwarding decisions based on destination IP addresses, which is the defining function of a router, not a switch (even a multilayer switch still uses MAC addresses for most forwarding unless explicitly configured for routing).
Detailed technical explanation
Routers use longest-prefix matching in their routing table to select the most specific route for a destination IP, and they decrement the Time-to-Live (TTL) field in the IP header to prevent loops. In real-world scenarios, a router can also perform Network Address Translation (NAT) to map private IPs to a public IP, or act as a firewall using access control lists (ACLs) that filter based on Layer 3 information.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
What to study next
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FAQ
Networking Concepts — This question tests Networking Concepts — Read the scenario before looking for a memorised answer..
The correct answer is: Router — A router operates at Layer 3 (Network layer) of the OSI model and uses the destination IP address in the packet header to make forwarding decisions. It maintains a routing table (e.g., via OSPF, EIGRP, or static routes) to determine the next-hop interface for each packet, enabling communication between different subnets or VLANs.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This N10-009 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 N10-009 exam.
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