hardMultiple Select
300-410 Practice Question: Which THREE symptoms indicate a problem with…
Which THREE symptoms indicate a problem with route redistribution causing suboptimal routing or routing loops? (Choose THREE.)
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
✓
Routing loops occur where packets traverse multiple routers repeatedly.
Route redistribution problems manifest in specific, observable ways. Option A is correct because a routing loop caused by mutual redistribution (for example, redistributing routes back and forth between OSPF and EIGRP without proper filtering or administrative distance/tagging) makes packets traverse multiple routers repeatedly until the TTL expires. Option B is correct because suboptimal routing occurs when a redistributed route's metric or administrative distance makes a longer path appear preferable to a shorter path that already exists within the same routing domain. Option D is correct because missing reachability to networks that exist in the redistribution router's table typically indicates a redistribution filter, missing redistribute statement, or a seed metric problem preventing those prefixes from being advertised into the target protocol. Option C is not a symptom of redistribution issues since low CPU utilization is normal and healthy, not indicative of loops or suboptimal paths. Option E is not a symptom either, because stable and fast-converging routing tables describe correct operation rather than a redistribution fault.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Routing loops occur where packets traverse multiple routers repeatedly.
Why this is correct
Routing loops arise when redistributed routes re-enter the source routing domain, so packets circulate between routers indefinitely. This directly satisfies the stem's requirement for a redistribution-induced symptom, since mismatched metrics or missing administrative distance controls let prefixes leak bidirectionally, producing the repeated multi-router traversal described.
- ✓
Traffic from one area takes a longer path than expected, even though a shorter path exists within the same routing domain.
Why this is correct
When redistribution injects routes with distorted metrics or administrative distance, a router may prefer a longer path over a shorter one inside the same domain. This suboptimal path selection is a direct symptom of faulty redistribution.
- ✗
CPU utilization on the redistribution router is consistently below 50%.
Why it's wrong here
Low CPU usage is normal healthy operation, not a redistribution fault symptom; suboptimal routing or loops typically show elevated CPU from repeated route recalculation. It is tempting because sustained high CPU is a genuine indicator of routing instability, so a low reading could be mistaken for reassurance rather than evidence against a redistribution problem.
- ✓
Some networks are not reachable from certain parts of the network, even though they are present in the routing table of the redistribution router.
Why this is correct
Partial reachability despite the prefix appearing in the redistribution router's table indicates routes are advertised into one domain but not redistributed back, or filtering drops them asymmetrically. This asymmetry between routing table presence and end-to-end reachability is a hallmark redistribution fault causing suboptimal paths or black holes.
- ✗
The routing table on all routers is stable and converges quickly after a topology change.
Why it's wrong here
Stable, fast-converging tables indicate redistribution is working correctly, so this contradicts the question rather than indicating a fault. It is tempting because convergence speed is a legitimate health metric for routing protocols, and slow convergence would indeed point to redistribution issues — but stability here is the opposite of the symptom sought.
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
Advanced EIGRP Features (Stub, Load Balancing, Named Mode)
Key term
Route Redistribution Between Protocols
Route redistribution between protocols is the process of taking routes learned from one routing protocol and injecting them into another routing protocol so that networks using different protocols can communicate.
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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.