Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A router learns 10.10.10.0/24 from OSPF and EIGRP at the same time. OSPF reports a metric of 20, and EIGRP reports a metric of 30720. Which route is installed in the routing table by default?
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
Distractor review
The OSPF route, because 20 is lower than 30720
Metrics are only compared within the same routing protocol, not across different ones.
B
Best answer
The EIGRP route, because its administrative distance is lower
Correct. EIGRP wins because its default administrative distance is lower than OSPF.
C
Distractor review
Both routes, because they point to the same prefix
Equal-cost load balancing does not occur across different protocols just because the destination matches.
D
Distractor review
Neither route, because the metrics are not comparable
One of the routes is selected; the metrics being different types does not prevent route installation.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is to assume that the router selects the route with the lowest metric value regardless of the routing protocol. In this question, the OSPF metric of 20 is numerically lower than the EIGRP metric of 30720, which tempts candidates to pick the OSPF route. However, metrics are only comparable within the same routing protocol. The router first compares administrative distance values, which are different for OSPF (110) and EIGRP (90). Because EIGRP has a lower administrative distance, its route is preferred and installed, despite its higher metric value. Misunderstanding this leads to incorrect answers.
Technical deep dive
How to think about this question
Routing protocols like OSPF and EIGRP use different metrics to evaluate the best path to a destination network. OSPF uses a cost metric based on bandwidth, while EIGRP uses a composite metric that includes bandwidth, delay, load, and reliability. However, when a router receives multiple routes to the same prefix from different routing protocols, it does not compare these metrics directly because they are protocol-specific and not comparable across protocols. Instead, Cisco routers use administrative distance (AD) as the primary criterion to select which route to install in the routing table when multiple routing protocols provide routes to the same destination. Administrative distance is a value that rates the trustworthiness of a routing source, with lower values being more preferred. EIGRP internal routes have a default AD of 90, while OSPF routes have an AD of 110, so the router installs the EIGRP route by default regardless of the metric values reported by each protocol. A common exam trap is to assume the router chooses the route with the lowest metric value across protocols, such as picking OSPF because 20 is less than 30720. This mistake ignores the role of administrative distance in route selection. In practical networking, understanding AD helps troubleshoot routing issues when multiple protocols coexist, ensuring predictable routing behavior and avoiding confusion caused by metric comparisons across different protocols.
KKey Concepts to Remember
- A Cisco router uses administrative distance to select the best route when multiple routing protocols provide routes to the same destination prefix.
- EIGRP internal routes have a default administrative distance of 90, making them more preferred than OSPF routes with an administrative distance of 110.
- Routing metrics such as OSPF cost and EIGRP composite metric are only compared within the same routing protocol, not across different protocols.
- The router installs the route with the lowest administrative distance into the routing table, regardless of the metric values reported by different protocols.
- When multiple routes to the same prefix exist, the router does not perform load balancing across different routing protocols by default.
- Administrative distance values are fixed defaults but can be manually adjusted to influence route selection in Cisco routers.
- Understanding the difference between routing protocol metrics and administrative distance is critical for predicting route installation behavior.
- Ignoring administrative distance and comparing metrics across protocols is a common exam trap that leads to incorrect route selection assumptions.
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?
A Cisco router uses administrative distance to select the best route when multiple routing protocols provide routes to the same destination prefix.
What is the correct answer to this question?
The correct answer is: The EIGRP route, because its administrative distance is lower — When the same prefix is learned from different routing protocols, the router compares administrative distance first. EIGRP internal routes use AD 90, while OSPF uses AD 110, so the EIGRP route is preferred.
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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