Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
R1# show ip route O 10.50.0.0/16 [110/20] via 192.0.2.2 R 10.50.0.0/16 [120/1] via 192.0.2.6
Based on the exhibit, what is the best explanation for why the router chooses the OSPF route to 10.50.0.0/16 instead of the RIP route?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Because OSPF has a lower administrative distance than RIP for the same prefix.
This is correct because both routes are /16, so source trust becomes decisive and OSPF wins.
B
Distractor review
Because RIP routes are never installed when OSPF is running.
This is wrong because RIP routes can exist in the table even when OSPF is present.
C
Distractor review
Because OSPF always has a longer prefix than RIP.
This is wrong because both routes shown are the same prefix length.
D
Distractor review
Because the RIP metric is lower than the OSPF metric.
This is wrong because cross-protocol selection here is decided by administrative distance, not that comparison.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is believing that RIP routes are never installed when OSPF is running or that the router always prefers the route with the lowest metric regardless of protocol. This is incorrect because RIP routes can remain in the routing table alongside OSPF routes. The router actually uses administrative distance, not metric, to choose between routes learned from different protocols. Confusing metric with administrative distance leads to wrong answers, especially when both protocols advertise the same prefix length. Remember, cross-protocol route selection depends on administrative distance, not metric comparison.
Technical deep dive
How to think about this question
Administrative distance (AD) is a key concept in Cisco routing that determines the trustworthiness of routing information from different routing protocols. Each routing protocol is assigned a default AD value, with lower values indicating higher trust. OSPF has a default AD of 110, while RIP has a default AD of 120. When a router learns about the same destination prefix from multiple protocols, it compares their AD values to decide which route to install in the routing table. When two routes to the same prefix length exist, the router uses the administrative distance as the tiebreaker. Since both OSPF and RIP advertise the 10.50.0.0/16 prefix in this scenario, the router compares their AD values and selects the route with the lower AD, which is OSPF. Metrics within each protocol are only compared when routes come from the same routing protocol; cross-protocol metric comparison does not influence route selection. A common exam trap is assuming that metrics alone determine route selection across protocols or that RIP routes are suppressed when OSPF is running. In reality, both routes can coexist in the routing table, but the router prefers the route with the lowest administrative distance. Understanding this distinction is critical for correctly answering questions about route selection in multi-protocol environments and for practical network troubleshooting.
KKey Concepts to Remember
- Administrative distance determines the trustworthiness of routing information from different routing protocols, with lower values indicating higher preference.
- OSPF has a default administrative distance of 110, which is lower than RIP's default administrative distance of 120.
- When multiple routes to the same prefix length exist, the router selects the route with the lowest administrative distance to install in the routing table.
- Metrics are only compared between routes learned from the same routing protocol and do not influence cross-protocol route selection.
- RIP routes can coexist in the routing table alongside OSPF routes if they advertise the same prefix, but OSPF routes are preferred due to lower administrative distance.
- Longest prefix match is the primary route selection criterion; when prefix lengths are equal, administrative distance becomes the deciding factor.
- Confusing metric comparison with administrative distance leads to incorrect route selection understanding in multi-protocol environments.
- Understanding administrative distance is essential for troubleshooting routing issues and correctly answering CCNA routing questions.
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Administrative distance determines the trustworthiness of routing information from different routing protocols, with lower values indicating higher preference.
What is the correct answer to this question?
The correct answer is: Because OSPF has a lower administrative distance than RIP for the same prefix. — The router chooses the OSPF route because when the prefix length is the same, source preference is considered, and OSPF has a lower administrative distance than RIP. In practical terms, both routes describe the same destination size, so longest-prefix match does not separate them. The router then trusts the OSPF source more than RIP by default. This is a classic administrative-distance comparison question and a very important route-selection concept.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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