hardMultiple ChoiceObjective-mapped
300-410 Practice Question: A BGP speaker R1 is advertising a prefix…
A BGP speaker R1 is advertising a prefix 10.10.0.0/16 to its eBGP neighbor R2. R2 is also receiving the same prefix from another eBGP neighbor R3 with a lower local preference. R1 configuration: router bgp 100, neighbor 192.168.1.2 remote-as 200, neighbor 192.168.1.2 route-map SET-LP in. Route-map SET-LP sets local-preference 150. R2 shows: 'show ip bgp 10.10.0.0/16' shows two paths: one from R1 with local pref 150, and one from R3 with local pref 100. The best path is via R3. Why is the path from R1 not selected?
⚠ Common exam trap
Cisco often tests the distinction between inbound and outbound route-map application on eBGP peers, specifically that local preference set inbound affects the local router's decision but is not sent to the neighbor, leading candidates to mistakenly think the neighbor will see the modified value.
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 route-map is applied inbound on R1, but it should be applied outbound to affect the local preference on routes sent to R2.
The route-map SET-LP is applied inbound on R1 (neighbor 192.168.1.2 route-map SET-LP in), which means it sets local preference on routes received from R2, not on routes sent to R2. Local preference is a BGP attribute that is propagated only to iBGP peers and is not exchanged between eBGP peers. To influence R2's best path selection, the route-map must be applied outbound on R1 (neighbor 192.168.1.2 route-map SET-LP out) so that the local-preference value is set on the update sent to R2. Since R1 sets local preference inbound, R2 never receives the modified value, and R2's best path selection defaults to the path from R3 with local preference 100, which is the only local preference R2 sees from R1 (default 100).
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 route-map is applied inbound on R1, but it should be applied outbound to affect the local preference on routes sent to R2.
Why this is correct
Inbound route-maps affect routes received from the neighbor; outbound affects routes sent. To set local preference on routes advertised to R2, the route-map must be applied outbound.
- ✗
The local-preference value of 150 is not high enough; it should be at least 200 to override the path from R3.
Why it's wrong here
Local preference 150 is higher than 100, so it should be preferred; the issue is that the value is not being applied to the advertised route.
- ✗
R2 has a route-map that sets local preference to 100 for all routes, overriding the value set by R1.
Why it's wrong here
No such route-map is mentioned; the scenario focuses on R1's configuration.
- ✗
The prefix 10.10.0.0/16 is not in the BGP table of R1 because it is not originated or learned.
Why it's wrong here
R1 is advertising the prefix, so it must be in its BGP table.
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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.