Question 718 of 2,152

BGP Troubleshooting →mediumMultiple ChoiceObjective-mapped

BGP Best Path Selection — Manipulating Local Preference to Prefer a Specific Path

This 300-410 practice question tests your understanding of bgp troubleshooting. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.

An engineer is troubleshooting a BGP route selection issue. Router R1 receives two paths for prefix 10.0.0.0/8: one from eBGP peer R2 (AS 65002) with weight 0, local preference 100, and AS path 65002; and another from eBGP peer R3 (AS 65003) with weight 0, local preference 200, and AS path 65003 65004. R1's BGP table shows the path from R3 as the best route. The engineer wants the path from R2 to be preferred. What should the engineer do?

A
Configure a route-map on R1 to set local preference 150 for routes from R2.
Why wrong: Setting local preference 150 is lower than the R3 path's 200, so R2 remains less preferred. Incorrect.
B
Configure a route-map on R1 to set local preference 250 for routes from R2.
Setting local preference 250 is higher than 200, so after weight comparison (both 0), R2 becomes the best path. Correct.
C
Configure a route-map on R1 to prepend two additional AS numbers to the AS path from R3.
Why wrong: Prepending AS path only affects AS path length comparison, which occurs after local preference. Since R2's local preference is lower, this change does not help. Incorrect.
D
Configure a route-map on R1 to set weight 100 for routes from R2.
Setting weight 100 makes R2's path have higher weight than R3's default weight 0. Weight is compared first, so R2 becomes the best path. Correct.

Full breakdown with real-world context →

Quick Answer

The answer is to configure a route-map on R1 that sets a local preference of 250 for routes received from R2. This works because BGP best path selection evaluates local preference before AS path length, so raising R2’s local preference above R3’s existing value of 200 makes R2’s path the best, regardless of the shorter AS path from R2. On the Cisco CCNP ENARSI 300-410 exam, this scenario tests your understanding of BGP path attribute order and the ability to manipulate path selection without altering other attributes. A common trap is assuming AS path length alone decides the winner, but local preference always takes precedence. Remember the mnemonic “We Love Oranges AS Oranges” to recall the BGP decision order: Weight, Local Preference, Originate, AS path, Origin, MED, and so on—local preference comes second, so it overrides AS path length every time.

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

✓

Configure a route-map on R1 to set local preference 250 for routes from R2.

BGP path selection compares weight first. Option D sets weight 100 for routes from R2 (default weight 0), making the R2 path preferred over R3's path (weight 0). Option B sets local preference 250, which is higher than R3's 200, so after weight tie (both 0) it wins. Option A sets local preference 150, which is lower than 200, so R3 still wins. Option C prepends AS numbers, which lengthens the AS path, making R3 path less preferred in AS path length comparison, but since local preference is compared first, this change is irrelevant because R2's local preference is lower than R3's. Thus only B and D achieve the goal.

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.

✗
Configure a route-map on R1 to set local preference 150 for routes from R2.
Why it's wrong here
Setting local preference 150 is lower than the R3 path's 200, so R2 remains less preferred. Incorrect.
✓
Configure a route-map on R1 to set local preference 250 for routes from R2.
Why this is correct
Setting local preference 250 is higher than 200, so after weight comparison (both 0), R2 becomes the best path. Correct.
Related concept
Read the scenario before looking for a memorised answer.
✗
Configure a route-map on R1 to prepend two additional AS numbers to the AS path from R3.
Why it's wrong here
Prepending AS path only affects AS path length comparison, which occurs after local preference. Since R2's local preference is lower, this change does not help. Incorrect.
✓
Configure a route-map on R1 to set weight 100 for routes from R2.
Why this is correct
Setting weight 100 makes R2's path have higher weight than R3's default weight 0. Weight is compared first, so R2 becomes the best path. Correct.
Related concept
Read the scenario before looking for a memorised answer.

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 300-410 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 300-410 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.

Related 300-410 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Layer 3 Technologies practice questions

Practise 300-410 questions linked to Layer 3 Technologies.

EIGRP Troubleshooting practice questions

Practise 300-410 questions linked to EIGRP Troubleshooting.

OSPF Troubleshooting (v2/v3) practice questions

Practise 300-410 questions linked to OSPF Troubleshooting (v2/v3).

BGP Troubleshooting practice questions

Practise 300-410 questions linked to BGP Troubleshooting.

Route Redistribution practice questions

Practise 300-410 questions linked to Route Redistribution.

Policy-Based Routing (PBR) practice questions

Practise 300-410 questions linked to Policy-Based Routing (PBR).

VRF-Lite practice questions

Practise 300-410 questions linked to VRF-Lite.

Route Maps and Route Filtering practice questions

Practise 300-410 questions linked to Route Maps and Route Filtering.

Administrative Distance practice questions

Practise 300-410 questions linked to Administrative Distance.

Route Summarization practice questions

Practise 300-410 questions linked to Route Summarization.

Bidirectional Forwarding Detection (BFD) practice questions

Practise 300-410 questions linked to Bidirectional Forwarding Detection (BFD).

VPN Technologies practice questions

Practise 300-410 questions linked to VPN Technologies.

Practice this exam

Start a free 300-410 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions 20 questions 30 questions 50 questions Timed 30

300-410 practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this 300-410 question test?

BGP Troubleshooting — This question tests BGP Troubleshooting — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Configure a route-map on R1 to set local preference 250 for routes from R2. — BGP path selection compares weight first. Option D sets weight 100 for routes from R2 (default weight 0), making the R2 path preferred over R3's path (weight 0). Option B sets local preference 250, which is higher than R3's 200, so after weight tie (both 0) it wins. Option A sets local preference 150, which is lower than 200, so R3 still wins. Option C prepends AS numbers, which lengthens the AS path, making R3 path less preferred in AS path length comparison, but since local preference is compared first, this change is irrelevant because R2's local preference is lower than R3's. Thus only B and D achieve the goal.

What should I do if I get this 300-410 question wrong?

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

About these practice questions

Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →

How Courseiva writes practice questions · Editorial policy

Keep practising

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

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.