hardMultiple ChoiceObjective-mapped
300-410 Practice Question: An engineer configures mutual redistribution…
An engineer configures mutual redistribution between OSPF and EIGRP. After a few minutes, the network becomes unstable with routing loops. The engineer checks the routing tables and notices that the same prefix is being learned from both protocols with different administrative distances. Which is the most likely explanation?
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
✓
Routes are redistributed back and forth between OSPF and EIGRP without any filtering or tagging
Mutual redistribution without proper route tagging can cause routing loops because each protocol redistributes routes back into the other, creating a feedback loop. The administrative distance of the redistributed routes may cause one protocol to prefer the redistributed route over the original, leading to instability. Using route tags and filtering can prevent this, but without them, loops are common.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Routes are redistributed back and forth between OSPF and EIGRP without any filtering or tagging
Why this is correct
Correct. Mutual redistribution without tagging or filtering causes a feedback loop, leading to routing loops.
- ✗
The seed metric for OSPF redistribution into EIGRP is not configured
Why it's wrong here
Missing seed metric would prevent redistribution from OSPF into EIGRP, not cause loops.
- ✗
The administrative distance of OSPF is lower than EIGRP, causing OSPF routes to be preferred
Why it's wrong here
AD differences can cause suboptimal routing but not necessarily loops; the loop is caused by the redistribution cycle.
- ✗
The redistribute command is missing the subnets keyword under OSPF
Why it's wrong here
Missing subnets keyword would only affect classful redistribution, not cause loops.
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.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 300-410 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 300-410 exam.