- A
The router installs only the EIGRP route because it has a lower administrative distance.
Why wrong: Administrative distance is compared only for routes with the same prefix length. Here the routes have different prefix lengths, so both are installed.
- B
Both the OSPF and EIGRP routes are installed in the routing table.
Since the routes have different prefix lengths, they are treated as separate destinations and both are installed.
- C
Traffic to 172.16.10.100 is forwarded using the OSPF route.
Why wrong: Longest-prefix matching selects the most specific route. Because 172.16.10.100 falls within the /24 subnet, the EIGRP route is used.
- D
The EIGRP route is used for all traffic destined to any address within 172.16.0.0/16.
Why wrong: The EIGRP route covers only the 172.16.10.0/24 subnet. Other subnets within the /16 still use the OSPF route.
- E
The OSPF route is used for destinations within 172.16.0.0/16 that are not part of the 172.16.10.0/24 subnet.
Because the /24 is a more specific route, the OSPF /16 serves as a covering route for any addresses that do not match the longer prefix.
Quick Answer
The correct answer is that both routes are installed in the routing table, with the OSPF /16 route used for destinations inside 172.16.0.0/16 that fall outside the more specific 172.16.10.0/24 subnet. This is because overlapping routes with different prefix lengths are not compared by administrative distance; instead, the router applies the longest prefix match rule for forwarding decisions. Since the /24 EIGRP route has a longer prefix, it wins for traffic destined to that exact subnet, while the /16 OSPF route covers the broader range. On the CCNA 200-301 v2 exam, this tests your understanding that prefix length takes priority over AD when routes overlap but have different subnet masks—a common trap is assuming the lower AD always wins. Remember the key distinction: AD resolves conflicts between identical prefix lengths, while longest match resolves conflicts between different prefix lengths. Memory tip: “Longer is stronger for forwarding; lower AD is only for identical roads.”
CCNA IP Routing Practice Question
This 200-301 practice question tests your understanding of ip routing. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
A router learns a route to 172.16.0.0/16 via OSPF (administrative distance 110) and a route to 172.16.10.0/24 via EIGRP (administrative distance 90). No other overlapping routes exist. Which TWO statements about how the router handles these routes are correct?
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
Both the OSPF and EIGRP routes are installed in the routing table.
B is correct because the router installs both routes in the routing table when they have different prefix lengths. The EIGRP route to 172.16.10.0/24 (AD 90) is more specific than the OSPF route to 172.16.0.0/16 (AD 110). The router uses the longest prefix match rule for forwarding, so both routes coexist without conflict.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The router installs only the EIGRP route because it has a lower administrative distance.
Why it's wrong here
Administrative distance is compared only for routes with the same prefix length. Here the routes have different prefix lengths, so both are installed.
- ✓
Both the OSPF and EIGRP routes are installed in the routing table.
Why this is correct
Since the routes have different prefix lengths, they are treated as separate destinations and both are installed.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Traffic to 172.16.10.100 is forwarded using the OSPF route.
Why it's wrong here
Longest-prefix matching selects the most specific route. Because 172.16.10.100 falls within the /24 subnet, the EIGRP route is used.
- ✗
The EIGRP route is used for all traffic destined to any address within 172.16.0.0/16.
- ✓
The OSPF route is used for destinations within 172.16.0.0/16 that are not part of the 172.16.10.0/24 subnet.
Why this is correct
Because the /24 is a more specific route, the OSPF /16 serves as a covering route for any addresses that do not match the longer prefix.
Related concept
Read the scenario before looking for a memorised answer.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Both the OSPF and EIGRP routes are installed in the routing table.Correct answer▾
Why this is correct
Since the routes have different prefix lengths, they are treated as separate destinations and both are installed.
✗The router installs only the EIGRP route because it has a lower administrative distance.Wrong answer — click to see why▾
Why this is wrong here
The router does not discard the OSPF route; it installs both /16 and /24 entries because they represent different network-specific entries.
✗Traffic to 172.16.10.100 is forwarded using the OSPF route.Wrong answer — click to see why▾
Why this is wrong here
The traffic matches the /24 route, not the /16, so it would be forwarded via the EIGRP next-hop.
✗The EIGRP route is used for all traffic destined to any address within 172.16.0.0/16.Wrong answer — click to see why▾
Why this is wrong here
The /24 is a subset; traffic outside 172.16.10.0/24 matches only the /16 OSPF route.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that administrative distance alone determines which route is installed, ignoring the critical role of prefix length in the longest prefix match rule.
Detailed technical explanation
How to think about this question
The routing table can hold multiple routes to overlapping networks as long as the prefix lengths differ. The forwarding decision is based on the longest prefix match algorithm, which selects the most specific route (longest subnet mask) regardless of administrative distance. In this scenario, the EIGRP route (172.16.10.0/24) is more specific than the OSPF route (172.16.0.0/16), so traffic to 172.16.10.x uses EIGRP, while traffic to other addresses in 172.16.0.0/16 uses OSPF.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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
Questions learners often ask
What does this 200-301 question test?
IP Routing — This question tests IP Routing — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Both the OSPF and EIGRP routes are installed in the routing table. — B is correct because the router installs both routes in the routing table when they have different prefix lengths. The EIGRP route to 172.16.10.0/24 (AD 90) is more specific than the OSPF route to 172.16.0.0/16 (AD 110). The router uses the longest prefix match rule for forwarding, so both routes coexist without conflict.
What should I do if I get this 200-301 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
This 200-301 practice question is part of Courseiva's free Cisco 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 200-301 exam.
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