mediumMultiple Choice
300-410 Practice Question: Which loop prevention mechanism is used by…
Which loop prevention mechanism is used by default in RIP within a VRF-Lite configuration?
⚠ Common exam trap
The trap is assuming VRF-Lite changes RIP's default loop prevention behavior — VRF-Lite isolates routing tables but does not alter protocol defaults, so split horizon remains the default.
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
✓
Split horizon
RIP uses split horizon as a default loop prevention mechanism, and this behavior is preserved within VRF-Lite configurations because VRF-Lite simply partitions the routing table without changing RIP's protocol behavior. Split horizon prevents a router from advertising a route back out the interface it learned it from.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Split horizon
Why this is correct
Split horizon is enabled by default on RIP interfaces, preventing a route from being advertised back out the interface it was learned on. Within a VRF-Lite configuration, each VRF maintains independent RIP routing instances, so split horizon operates per-VRF to block two-router loops without additional configuration.
- ✗
Route poisoning
Why it's wrong here
Route poisoning advertises an unreachable metric to accelerate convergence, not to prevent loops; RIP's default loop prevention is split horizon with poison reverse. It is tempting because route poisoning is a legitimate RIP mechanism, and it would be relevant when deliberately triggering immediate route withdrawal.
- ✗
Hold-down timer
Why it's wrong here
Hold-down timers delay accepting a route after it is declared unreachable; they suppress flapping routes rather than preventing RIP's counting-to-infinity loop. It is tempting because hold-downs are a legitimate stability mechanism in distance-vector protocols, but split horizon and route poisoning are the default loop prevention.
- ✗
TTL expiry
Why it's wrong here
TTL expiry limits how far packets travel hop-by-hop; it operates on forwarded data traffic, not on RIP routing updates within the VRF. It is tempting because TTL is a genuine loop mitigation at Layer 3, but RIP relies on split horizon and route poisoning instead.
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 and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.