hardMultiple ChoiceObjective-mapped
300-410 Practice Question: Is troubleshooting an MPLS L3VPN where CE1 can…
A network engineer is troubleshooting an MPLS L3VPN where CE1 can ping the PE1 interface but cannot ping CE2. On PE1, show ip route vrf CUSTOMER shows the route to CE2's subnet, but show bgp vpnv4 unicast all neighbors 10.0.0.2 advertised-routes does not show the route. The BGP session between PE1 and PE2 is established. What is the most likely 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
✓
A route-map applied to the VRF export is filtering the route.
The route is present in the VRF but not advertised to the remote PE, indicating a BGP policy issue. Since the BGP session is up, the most likely cause is that the route is not being redistributed into BGP or is being filtered by a route-map or prefix-list on the VRF export.
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 VRF export route-target does not match the import route-target on the remote PE.
Why it's wrong here
Incorrect because route-target mismatch would affect import on the remote PE, not advertisement from the local PE; the route would still be advertised.
- ✓
A route-map applied to the VRF export is filtering the route.
Why this is correct
Correct because a route-map on VRF export can filter routes before they are advertised to BGP, preventing the route from being sent to the remote PE.
- ✗
The BGP session is not using the correct update-source.
Why it's wrong here
Incorrect because the BGP session is established, so the update-source is correct; the issue is with route advertisement, not session establishment.
- ✗
The next-hop-self command is missing under the VRF address-family.
Why it's wrong here
Incorrect because next-hop-self affects the next-hop attribute, not whether the route is advertised; the route would still be sent.
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Related to this question
Learn chapter
Introduction to ENARSI Exam and Network Fundamentals
Key term
MPLS Layer 3 VPN
A technology that uses Multiprotocol Label Switching to create secure, scalable virtual private networks that connect multiple sites at the network layer, where the service provider manages routing between customer sites.
Key term
LDP Protocol
LDP, or Label Distribution Protocol, is a protocol that routers use to automatically exchange labels that enable MPLS (Multiprotocol Label Switching) to create fast, efficient paths for data packets across a network.
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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.