CCNA IP Routing Practice Question
A network engineer notices that traffic from the router to server 192.168.10.5 is being sent over a slow backup link, even though the primary high-speed link is up. The routing table has an OSPF route for 192.168.10.0/24 via the primary link and a static host route to 192.168.10.5/32 via the backup link. Why is the backup link used for traffic to the server?
⚠ Common exam trap
Cisco often tests the misconception that administrative distance is the sole factor in route selection, when in fact the longest prefix match rule is evaluated first and takes priority over AD for any routes that are already in the routing table.
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 static /32 route is a more specific match than the OSPF /24 route, so it is selected regardless of administrative distance.
The router uses the most specific matching route in the routing table to forward traffic. The static host route to 192.168.10.5/32 has a longer prefix length (32 bits) than the OSPF route for 192.168.10.0/24 (24 bits), making it a more specific match. Even though OSPF has a higher administrative distance, the longest prefix match rule takes precedence over administrative distance when both routes are present in the routing table.
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 static route has an administrative distance of 1, which is lower than OSPF's 110, so it is always preferred.
Why it's wrong here
Administrative distance is only used to choose between two routes that have the exact same destination prefix and mask. Here, the static route is a /32 while the OSPF route is a /24, so they are different prefix lengths and the router first applies the longest-match rule. A lower AD cannot make a less specific route win over a more specific one, so this claim is incorrect.
- ✗
The router is load-balancing between the two routes, and traffic is being hashed to the backup link for this particular flow.
Why it's wrong here
Load balancing occurs when multiple routes have the same prefix length, the same administrative distance, and equal metric. The /32 and /24 routes do not meet these criteria; they are not equal-cost, and they differ in prefix length. In fact, the router forwards traffic solely based on the longest-prefix match, not via hashing across routes of different specificity.
- ✗
The OSPF route is not installed in the routing table because the static route has a better AD.
Why it's wrong here
The routing table can hold both routes because they have different prefix lengths; the OSPF /24 and static /32 are not competing for the same entry. The static route's AD of 1 only matters when comparing routes to the exact same destination prefix. Therefore, the OSPF /24 route will still be installed and used for other addresses within 192.168.10.0/24, such as 192.168.10.6.
- ✓
The static /32 route is a more specific match than the OSPF /24 route, so it is selected regardless of administrative distance.
Why this is correct
The router selects the static /32 route because it offers the longest prefix match for destination 192.168.10.5. Even though OSPF has a higher administrative distance, prefix length is evaluated first in the forwarding decision. The /32 route exactly matches the destination, whereas the /24 route only matches the general subnet, so the more specific route is always chosen.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓The static /32 route is a more specific match than the OSPF /24 route, so it is selected regardless of administrative distance.Correct answer▾
Why this is correct
The router selects the static /32 route because it offers the longest prefix match for destination 192.168.10.5. Even though OSPF has a higher administrative distance, prefix length is evaluated first in the forwarding decision. The /32 route exactly matches the destination, whereas the /24 route only matches the general subnet, so the more specific route is always chosen.
✗The static route has an administrative distance of 1, which is lower than OSPF's 110, so it is always preferred.Wrong answer — click to see why▾
Why this is wrong here
Administrative distance is only compared when two routes have the same prefix length. Here, the /32 route has a longer prefix, so it is chosen first.
✗The router is load-balancing between the two routes, and traffic is being hashed to the backup link for this particular flow.Wrong answer — click to see why▾
Why this is wrong here
Load balancing requires routes with identical prefix lengths and metrics. The /32 and /24 routes are treated as different destinations.
✗The OSPF route is not installed in the routing table because the static route has a better AD.Wrong answer — click to see why▾
Why this is wrong here
AD is only compared when routes have the exact same prefix length. The routing table can hold multiple overlapping routes as long as they differ in prefix length.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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
OSPFv3 Single-Area Configuration for IPv6
Key term
Longest prefix match
Longest prefix match is the algorithm routers use to select the most specific route from a routing table when forwarding a packet to its destination.
Key term
Route
A route is a path that data takes through a network from one device or network to another, determined by routing protocols and configured rules.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 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 200-301 exam.