mediumMultiple Choice
300-410 Practice Question: Which OSPF LSA type is used to advertise a…
Which OSPF LSA type is used to advertise a summary route for a network outside the area but within the same OSPF domain?
⚠ Common exam trap
The trap is confusing Type 3 with Type 5: candidates may think that any route outside the local area is 'external' and thus Type 5, but Type 5 is only for routes outside the OSPF domain (e.g., redistributed from EIGRP).
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
✓
Type 3
OSPF Type 3 LSAs (Summary LSAs) are generated by Area Border Routers (ABRs) to advertise networks from one area into another area within the same OSPF domain. They describe inter-area routes, which are routes to networks outside the local area but still within the OSPF autonomous system. Therefore, a summary route for a network outside the area but within the same OSPF domain is advertised via Type 3 LSA.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Type 1
Why it's wrong here
Type 1 LSAs flood router and link states within one area only, so they cannot summarise a route from outside that area. Type 3 carries inter-area summary prefixes between areas of the same domain, which is the requirement here; Type 1 suits intra-area topology only.
- ✗
Type 2
Why it's wrong here
Type 2 LSAs describe transit networks via the DR, remaining within a single area and never summarising external destinations. Type 5 handles external routes, while Type 3 advertises inter-area summaries; Type 2 would be right only when representing a multi-access segment's DR.
- ✓
Type 3
Why this is correct
Type 3 LSAs are generated by ABRs to advertise inter-area routes, including summary routes for networks in other areas of the same OSPF domain. Type 5 handles external routes, so Type 3 matches the scenario.
- ✗
Type 5
Why it's wrong here
Type 5 LSAs advertise external destinations redistributed from outside the OSPF domain, carrying the ASBR's router ID. The stem requires an inter-area summary generated by an ABR, which is Type 3. Type 5 is tempting because it also represents routes learned elsewhere, but that elsewhere is another routing protocol, not another area.
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.