hardMultiple ChoiceObjective-mapped
300-410 Practice Question: BGP attribute manipulation causes unexpected path…
BGP attribute manipulation causes unexpected path selection. Router R1 and R2 are eBGP peers. R1 receives prefix 172.16.0.0/16 from R2 with MED 50 and from another peer R3 with MED 100. R1 has configuration: 'route-map SET-MED permit 10 set metric 200' applied to neighbor R2 inbound. R1 shows 'show ip bgp 172.16.0.0' output: 'BGP routing table entry for 172.16.0.0/16, version 2, Paths: (2 available, best #2) Path #1: from R2 with MED 200, Path #2: from R3 with MED 100'. The best path is via R3, but the network expects R2 to be preferred. What is the root cause?
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 'bgp always-compare-med' command is missing, causing MED to be ignored for paths from different ASes.
BGP best path selection uses MED only if paths are from the same AS (if 'bgp always-compare-med' is not configured). Since R2 and R3 are different ASes, MED is not compared; instead, the next tie-breaker (e.g., IGP metric to next-hop) selects R3. The route-map sets MED on R2's routes, but it does not affect the comparison because of AS path difference.
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 'bgp always-compare-med' command is missing, causing MED to be ignored for paths from different ASes.
Why this is correct
Without this command, MED is only compared within same AS, so R2's lower MED (200 vs 100) is not considered, and R3's path is chosen.
- ✗
The route-map SET-MED should be applied outbound on R2, not inbound.
Why it's wrong here
Inbound sets MED on received routes, which is correct.
- ✗
R2's next-hop is unreachable via IGP, causing R1 to ignore R2's path.
Why it's wrong here
Both paths are available.
- ✗
R1 has 'bgp bestpath med missing-as-worst' configured, causing missing MED to be treated as worst.
Why it's wrong here
MED is set, not missing.
Go deeper
Related to this question
About these practice questions
One of 1,966 original 300-410 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.