- A
The static route
Why wrong: Static preference 5 is higher than 0, so loses to direct.
- B
No route is active due to multiple routes
Why wrong: The direct route is active; others remain hidden.
- C
The OSPF route
Why wrong: OSPF preference 10 is higher than direct and static.
- D
The directly connected route
Direct routes have preference 0, which is the lowest possible, so they are always preferred.
Question 217 of 514
Understanding Junos Route Preference: Direct, Static, OSPF
This JNCIA-JUNOS practice question tests your understanding of routing fundamentals. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A router has a directly connected route to 10.10.10.0/24 on interface ge-0/0/0.0, a static route to the same prefix with next-hop 192.168.1.1, and an OSPF route to the same prefix. Which route is active in the routing table?
Quick Answer
The directly connected route is the active route in the routing table because it carries a Junos route preference of 0, the lowest possible value, making it unbeatable when the interface is up. In Junos, route preference is the tiebreaker when multiple routing protocols learn the same destination; direct routes (preference 0) always win over static routes (preference 5) and OSPF internal routes (preference 10). This concept is a core topic on the JNCIA-Junos exam, often appearing in route preference comparison questions designed to test your understanding of how Junos selects the active route. A common trap is assuming a static route overrides a direct route, but remember that direct routes are always preferred because they represent the interface itself. For a quick memory tip: think of the preference numbers as a race—zero is the starting line, and no other protocol can cross it first.
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 directly connected route
In Junos, the routing table (inet.0) selects the active route based on the route preference (administrative distance). Directly connected routes have a default preference of 0, which is the lowest possible value, making them preferred over static routes (default preference 5) and OSPF routes (preference 10 for intra-area, 150 for external). Therefore, the directly connected route to 10.10.10.0/24 on ge-0/0/0.0 is active.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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
Why it's wrong here
Static preference 5 is higher than 0, so loses to direct.
- ✗
No route is active due to multiple routes
Why it's wrong here
The direct route is active; others remain hidden.
- ✗
The OSPF route
Why it's wrong here
OSPF preference 10 is higher than direct and static.
- ✓
The directly connected route
Why this is correct
Direct routes have preference 0, which is the lowest possible, so they are always preferred.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates familiar with Cisco IOS might assume static routes (AD 1) are preferred over OSPF (AD 110) but forget that directly connected routes (AD 0) always take precedence, or they might think multiple routes cause a tie or require load-balancing, which is incorrect for a single active route selection.
Detailed technical explanation
How to think about this question
Junos uses the route preference value to determine which route is installed in the forwarding table (FIB). The directly connected route's preference of 0 is hardcoded and cannot be changed, ensuring it always wins unless the interface is down. In contrast, Cisco IOS uses administrative distance, where a directly connected route has a distance of 0 as well, but the behavior is identical; the key difference is that Junos explicitly lists preference values in the routing table output (e.g., 'pref 0').
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
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.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this JNCIA-JUNOS question test?
Routing Fundamentals — This question tests Routing Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The directly connected route — In Junos, the routing table (inet.0) selects the active route based on the route preference (administrative distance). Directly connected routes have a default preference of 0, which is the lowest possible value, making them preferred over static routes (default preference 5) and OSPF routes (preference 10 for intra-area, 150 for external). Therefore, the directly connected route to 10.10.10.0/24 on ge-0/0/0.0 is active.
What should I do if I get this JNCIA-JUNOS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Same concept, more angles
4 more ways this is tested on JNCIA-JUNOS
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A network engineer configures a static route to 10.0.0.0/8 with a preference of 20. An OSPF internal route to 10.0.0.0/8 has a default preference of 10. Which route will be active in the routing table?
medium- A.Both routes, because they have different protocols.
- B.Neither, because of a conflict.
- ✓ C.The OSPF route, because of lower preference.
- D.The static route, because it is manually configured.
Why C: In Junos, the active route in the routing table is determined by the lowest preference value. OSPF internal routes have a default preference of 10, while static routes have a default preference of 5, but here the static route is configured with a preference of 20. Since OSPF's preference (10) is lower than the static route's preference (20), the OSPF route is chosen as active.
Variation 2. What is the default preference value of a directly connected (direct) route in JunOS?
easy- A.10
- B.170
- ✓ C.0
- D.100
Why C: In JunOS, directly connected routes have a default preference value of 0, which is the highest possible preference (lowest numerical value). This ensures that directly connected routes are always preferred over routes learned from any dynamic routing protocol, as they represent interfaces that are directly reachable on the local device.
Variation 3. What is the default preference of a direct route in Junos?
easy- ✓ A.0
- B.10
- C.5
- D.15
Why A: Direct routes in Junos have a default preference of 0, which is the highest possible preference (lowest numerical value). This ensures that directly connected routes are always preferred over any other route type, including static routes (preference 5) and OSPF internal routes (preference 10). The preference value is used by Junos to select the best route when multiple routes exist to the same destination.
Variation 4. A Juniper device receives several routes to the same destination prefix from different routing protocols. Which parameter is used first to select the active route?
easy- ✓ A.Route preference (administrative distance)
- B.Metric
- C.AS path length
- D.Local preference
Why A: When a Juniper device receives multiple routes to the same destination prefix from different routing protocols, the route preference (also known as administrative distance) is the first tiebreaker used to select the active route. Each protocol has a default preference value (e.g., OSPF internal routes have a preference of 10, while static routes have a preference of 5), and the route with the lowest preference is chosen as active. This occurs before any metric or other path attribute is considered.
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Last reviewed: Jul 4, 2026
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