The answer is preference and metric. Junos first compares the route preference value, where a lower number indicates a more trusted source; if multiple routes share the same preference, it then uses the metric, also known as the cost, with a lower metric being preferred. On the JNCIA-Junos exam, this concept tests your understanding of the route selection algorithm, often appearing in multiple-choice questions that ask for the primary tie-breakers. A common trap is confusing route age or next-hop type as primary factors—while age can serve as a final tie-breaker after metric, preference and metric are the two decisive criteria Junos evaluates first. To remember the order, think “Preference first, then metric,” or use the mnemonic “Prefer Metrics” to recall that preference always precedes metric in the best route selection process.
JNCIA-JUNOS Routing Fundamentals Practice Question
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.
Which two factors does Junos use to select the best route when multiple routes to the same prefix exist? (Choose two.)
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Route preference
The correct answers are A and B. Junos first compares route preference; if equal, then metric is used. Next-hop type, route age, and number of hops are not standard tie-breakers. Option C is not used. Option D (route age) might be used as a final tie-breaker? Actually Junos does use route age as a tie-breaker after metric? But in JNCIA, preference and metric are the primary factors. I'll stick with A and B.
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.
✓
Route preference
Why this is correct
Lower preference is preferred; this is the primary selection criterion.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Next-hop type
Why it's wrong here
Next-hop type (e.g., direct vs. indirect) does not influence selection; it's a result of routing.
✗
Number of hops
Why it's wrong here
Number of hops is not used; metric covers path cost.
✓
Metric
Why this is correct
When preferences are equal, lower metric is chosen.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Route age
Why it's wrong here
Route age is not a standard tie-breaker in Junos; preference and metric are used.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 practitioner preparing for the JNCIA-JUNOS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which JNCIA-JUNOS exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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: Route preference — The correct answers are A and B. Junos first compares route preference; if equal, then metric is used. Next-hop type, route age, and number of hops are not standard tie-breakers. Option C is not used. Option D (route age) might be used as a final tie-breaker? Actually Junos does use route age as a tie-breaker after metric? But in JNCIA, preference and metric are the primary factors. I'll stick with A and B.
What should I do if I get this JNCIA-JUNOS question wrong?
Identify which JNCIA-JUNOS exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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