mediumMultiple Choice
350-401 Practice Question: Runs the following command on Router R3: R3# show…
A network engineer runs the following command on Router R3:
R3# show ip route ospf
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP a - application route + - replicated route, % - next hop override
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 5 subnets, 3 masks
O IA 10.1.1.0/24 [110/20] via 192.168.1.1, 00:12:34, GigabitEthernet0/0
O 10.2.2.0/24 [110/10] via 192.168.1.2, 00:15:22, GigabitEthernet0/0
O E2 10.3.3.0/24 [110/20] via 192.168.1.3, 00:08:11, GigabitEthernet0/0
Based on this output, what can be concluded?
⚠ Common exam trap
Cisco often tests the difference between OSPF external type 1 (E1) and type 2 (E2) routes, specifically that E2 routes do not include the internal cost to the ASBR, which is a common misconception that leads candidates to incorrectly select option C.
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
✓
The route to 10.3.3.0/24 is an external route redistributed into OSPF.
The route to 10.3.3.0/24 is marked as 'O E2' in the output, which stands for OSPF external type 2. This indicates that the route was redistributed into OSPF from another routing protocol or a different OSPF process, making it an external route. The 'E2' designation confirms it is an external route with a fixed metric that does not include the internal cost to the ASBR.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The route to 10.3.3.0/24 is an external route redistributed into OSPF.
Why this is correct
The route to 10.3.3.0/24 is an external route redistributed into OSPF. In the routing table, the code 'O E2' explicitly marks this as an OSPF external route of type 2. Type 2 (E2) routes are routes that originated outside the OSPF domain and were redistributed into OSPF, typically from another routing protocol such as EIGRP or BGP. The external cost is carried as configured on the ASBR, and in this case the metric of 20 is the default external cost for redistributed routes, confirming the redistributed origin.
- ✗
The route to 10.1.1.0/24 is in the same OSPF area as R3.
Why it's wrong here
The route to 10.1.1.0/24 is in the same OSPF area as R3. The routing table entry for 10.1.1.0/24 shows 'O IA', which stands for OSPF Inter-Area route. An IA route means the network belongs to a different OSPF area than the one in which R3 resides; it was advertised by an Area Border Router (ABR) using a Type 3 LSA. Therefore, it is not in the same area as R3 — it is from another area.
- ✗
The metric for 10.3.3.0/24 includes the internal cost to the ASBR.
Why it's wrong here
The metric for 10.3.3.0/24 includes the internal cost to the ASBR. For an OSPF External Type 2 (E2) route, the metric shown in the routing table is the external cost only — the cost configured or advertised by the ASBR — and does not include the internal OSPF cost from R3 to the ASBR. This is a key distinction between E1 and E2 routes: E1 adds the internal cost to the external cost, while E2 does not. Since the displayed metric is 20 and the route type is E2, the internal cost is intentionally omitted.
- ✗
R3 is an ASBR.
Why it's wrong here
R3 is an ASBR. The routing table output on R3 shows it receiving external routes (O E2 for 10.3.3.0/24), which only indicates that some other router redistributed those routes into OSPF. An Autonomous System Boundary Router (ASBR) is a router that injects external routes into OSPF, but nothing in the output suggests R3 is performing that redistribution. R3 is simply an internal OSPF router learning about the external routes via LSAs, not the source of those routes.
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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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 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 350-401 exam.