CCNA IP Routing Practice Question
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
What is the best explanation for why a router chooses the OSPF route to 10.50.0.0/16 instead of the RIP route?
⚠ Common exam trap
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.
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
✓
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.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Because OSPF has a lower administrative distance than RIP for the same prefix.
Why this is correct
Cisco IOS selects the route with the lowest administrative distance when multiple routing protocols offer the same destination and prefix length. OSPF's default administrative distance is 110, while RIP's is 120, so OSPF is considered more trustworthy and its route is installed in the routing table. Because both routes share the same /16 prefix, prefix length cannot break the tie, and the lower AD for OSPF becomes the decisive factor.
- ✗
Because RIP routes are never installed when OSPF is running.
Why it's wrong here
It is not true that RIP routes are always excluded whenever OSPF is running; a router can run both protocols simultaneously, and RIP may still install routes for any destination prefixes that OSPF does not know. Even for the same prefix, the lost route is simply not chosen for the RIB, but the RIP route may still appear as a candidate or in the routing database. The exhibit specifically shows both routes present, which disproves the absolute claim that RIP can never be installed.
When this WOULD be correct
In a scenario where the question specifies that RIP is configured but not allowed to run simultaneously with OSPF due to network policy or configuration settings, this option could be correct. For instance, if the exam question states that RIP is disabled when OSPF is active, then this answer would be valid.
- ✗
Because OSPF always has a longer prefix than RIP.
Why it's wrong here
This explanation cannot be correct because the exhibit shows both OSPF and RIP advertising the exact same /16 prefix, so there is no difference in prefix length to favor OSPF. Routing table selection only uses longest match when prefixes actually differ; when they are identical, the router must rely on administrative distance instead. Therefore, stating that OSPF always has a longer prefix is factually false in this topology and also a misunderstanding of the route selection process.
When this WOULD be correct
In a scenario where a question specifies that OSPF is the only routing protocol running on the router, and it asks why no RIP routes are present, this option could be correct, as it would imply that RIP routes cannot be installed without the protocol being active.
- ✗
Because the RIP metric is lower than the OSPF metric.
Why it's wrong here
Metrics are protocol-specific and not directly comparable: RIP uses hop count, while OSPF uses a cost derived from interface bandwidth, so a lower RIP metric does not imply a better route across protocols. The routing table decision first compares administrative distance, and only if the ADs are equal does the router consider metric values. Since OSPF's AD (110) is lower than RIP's (120), the OSPF route is selected regardless of which metric number happens to be smaller.
When this WOULD be correct
In a scenario where a question specifies that OSPF is configured to ignore RIP routes due to a specific policy or configuration, such as route filtering or administrative settings that prevent RIP from being used, this option would be correct.
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.
✓Because OSPF has a lower administrative distance than RIP for the same prefix.Correct answer▾
Why this is correct
Cisco IOS selects the route with the lowest administrative distance when multiple routing protocols offer the same destination and prefix length. OSPF's default administrative distance is 110, while RIP's is 120, so OSPF is considered more trustworthy and its route is installed in the routing table. Because both routes share the same /16 prefix, prefix length cannot break the tie, and the lower AD for OSPF becomes the decisive factor.
✗Because RIP routes are never installed when OSPF is running.Wrong answer — click to see why▾
Why this is wrong here
RIP routes can coexist with OSPF routes in the routing table for different prefixes, but for the same prefix, the router selects based on administrative distance, not protocol presence. This statement is factually incorrect as RIP routes are installed when they are the best source for a prefix.
★ When this WOULD be the correct answer
In a scenario where the question specifies that RIP is configured but not allowed to run simultaneously with OSPF due to network policy or configuration settings, this option could be correct. For instance, if the exam question states that RIP is disabled when OSPF is active, then this answer would be valid.
Why candidates choose this
Students might think OSPF overrides RIP entirely because OSPF is more advanced, but routing protocols operate independently and routes are selected per prefix based on AD.
✗Because OSPF always has a longer prefix than RIP.Wrong answer — click to see why▾
Why this is wrong here
Both routes in the exhibit have the same prefix length (/16), so prefix length is not a factor. OSPF does not inherently have longer prefixes; prefix length depends on the network design.
★ When this WOULD be the correct answer
In a scenario where a question specifies that OSPF is the only routing protocol running on the router, and it asks why no RIP routes are present, this option could be correct, as it would imply that RIP routes cannot be installed without the protocol being active.
Why candidates choose this
Test-takers may confuse the concept of longest prefix match with administrative distance, thinking a more specific route always wins, but here both are equally specific.
✗Because the RIP metric is lower than the OSPF metric.Wrong answer — click to see why▾
Why this is wrong here
Metrics are only comparable within the same routing protocol; OSPF uses cost and RIP uses hop count, so they cannot be directly compared. The router uses administrative distance to choose between different protocols.
★ When this WOULD be the correct answer
In a scenario where a question specifies that OSPF is configured to ignore RIP routes due to a specific policy or configuration, such as route filtering or administrative settings that prevent RIP from being used, this option would be correct.
Why candidates choose this
Students often assume lower metric always means better route, but cross-protocol selection ignores metrics and relies on AD first.
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?”
Visual reference
Quick reference
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
Learn chapter
Interpreting HSRP and VRRP Operational Status
Key term
OSPF
OSPF is a link-state routing protocol used to find the best path for data packets to travel across IP networks, like a smart GPS that recalculates routes when traffic changes.
Key term
RIP
RIP (Routing Information Protocol) is a distance-vector routing protocol that routers use to exchange information about network paths to determine the best route for data packets based on hop count.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.