CCNA IP Routing Practice Question
Exhibit
R3 routing candidates for 10.50.0.0/16: via 10.0.23.2 cost 20 via 10.0.34.4 cost 20 Both learned as OSPF intra-area routes
Exhibit: R3 learns 10.50.0.0/16 by OSPF through two equal-cost paths. What will R3 do by default?
⚠ Common exam trap
A frequent exam trap is believing that OSPF will choose only one route when multiple equal-cost paths exist, often assuming it picks the route from the neighbor with the highest router ID or the path with the lowest next-hop IP address. This misconception leads to incorrect answers because OSPF’s path selection process installs all equal-cost routes by default. Misunderstanding this behavior can cause candidates to overlook OSPF’s load balancing capability and mistakenly select options that describe single-route preferences, which do not apply to equal-cost multipath scenarios.
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
✓
Install both routes and load balance
When OSPF has equal-cost routes to the same destination, the router installs multiple paths and can load balance across them, assuming the platform supports the default maximum-paths value.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Install both routes and load balance
Why this is correct
OSPF's cost-based shortest path algorithm can yield multiple paths with identical metric to the same destination. By default, the router installs all such equal-cost paths into its routing table, up to the maximum-paths limit, and load balances traffic across them. Since both paths are equal cost, the router does not pick one over the other; it uses them together for traffic sharing.
- ✗
Choose the route from the neighbor with the highest router ID only
Why it's wrong here
OSPF path selection for equal-cost routes never consults neighbor router ID as a tie-breaker. The OSPF metric (cost) determines preferability; when costs are equal, the router installs all such paths. Router ID is used for OSPF neighbor identification and DR/BDR election, but it has no role in deciding which equal-cost path to keep. Therefore, choosing a path based on higher router ID is not a standard OSPF behavior.
When this WOULD be correct
In a different scenario where the question specifies that OSPF is configured to select routes based on router ID due to a specific policy or configuration, this option could be correct. For example, if the exam question stated that OSPF was modified to prefer routes based on router ID in a unique network setup.
- ✗
Install only one route because OSPF does not support ECMP
Why it's wrong here
The statement that OSPF does not support ECMP is factually incorrect. OSPF explicitly supports equal-cost multipath routing, and a router will install multiple equal-cost routes to a destination. This behavior is enabled by default, so the router would accept both equal-cost paths rather than installing only one. Thus, declaring that OSPF lacks ECMP is not a valid rationale for choosing a single route.
When this WOULD be correct
In a different scenario where the question specifies a routing protocol that does not support ECMP, such as RIP, the correct answer could be that only one route is installed. For example, if the question stated that R3 learns routes via RIP instead of OSPF, this option would be accurate.
- ✗
Prefer the path with the lower next-hop IP address
Why it's wrong here
Lower next-hop IP address does not factor into OSPF's route selection for equal-cost paths. OSPF relies solely on the routing metric (cost) to determine the best path, and when multiple paths share the same cost, all are installed. The next-hop IP address may be used in other routing protocols or for forwarding decisions, but it is not a tie-breaker for OSPF route preference. So, preferring the lower next-hop IP address is not a valid OSPF selection criterion.
When this WOULD be correct
In a scenario where a routing protocol explicitly states to prefer paths based on the next-hop IP address, such as in a question about EIGRP or a custom routing policy, this option would be correct. For example, if the question specified that only one route should be chosen based on the next-hop IP address, then this option would apply.
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.
✓Install both routes and load balanceCorrect answer▾
Why this is correct
OSPF's cost-based shortest path algorithm can yield multiple paths with identical metric to the same destination. By default, the router installs all such equal-cost paths into its routing table, up to the maximum-paths limit, and load balances traffic across them. Since both paths are equal cost, the router does not pick one over the other; it uses them together for traffic sharing.
✗Choose the route from the neighbor with the highest router ID onlyWrong answer — click to see why▾
Why this is wrong here
This option is incorrect because OSPF does not select routes based solely on the router ID; it uses metrics such as cost to determine the best path. In the context of equal-cost multi-path (ECMP), both routes would be installed by default.
★ When this WOULD be the correct answer
In a different scenario where the question specifies that OSPF is configured to select routes based on router ID due to a specific policy or configuration, this option could be correct. For example, if the exam question stated that OSPF was modified to prefer routes based on router ID in a unique network setup.
Why candidates choose this
Candidates may find this option tempting due to a common misconception that OSPF prioritizes router IDs in route selection, especially if they have encountered scenarios where router IDs are relevant in other protocols or configurations.
✗Install only one route because OSPF does not support ECMPWrong answer — click to see why▾
Why this is wrong here
This option is incorrect because OSPF does support Equal-Cost Multi-Path (ECMP) routing, allowing multiple routes to be installed in the routing table when they have the same cost.
★ When this WOULD be the correct answer
In a different scenario where the question specifies a routing protocol that does not support ECMP, such as RIP, the correct answer could be that only one route is installed. For example, if the question stated that R3 learns routes via RIP instead of OSPF, this option would be accurate.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of OSPF's capabilities, mistakenly believing that OSPF does not allow multiple equal-cost routes due to confusion with other protocols that have similar limitations.
✗Prefer the path with the lower next-hop IP addressWrong answer — click to see why▾
Why this is wrong here
This option is incorrect because OSPF does not prioritize routes based solely on the next-hop IP address; it uses equal-cost multi-path (ECMP) routing to install multiple routes when they have the same cost.
★ When this WOULD be the correct answer
In a scenario where a routing protocol explicitly states to prefer paths based on the next-hop IP address, such as in a question about EIGRP or a custom routing policy, this option would be correct. For example, if the question specified that only one route should be chosen based on the next-hop IP address, then this option would apply.
Why candidates choose this
Candidates may find this option tempting due to a common misconception that routing protocols always prefer lower next-hop IP addresses, which is a principle in some protocols but not in OSPF's ECMP context.
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
OSPFv3 Single-Area Configuration for IPv6
Key term
OSPF
OSPF is a link-state routing protocol that uses the SPF algorithm to compute the shortest path to each destination within a single autonomous system.
Key term
Router
A router is a networking device that connects different networks together and directs data traffic between them by choosing the best path for data to travel.
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JA
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.