The answer is that neighbor 10.0.0.6 is not sending any prefixes, as shown by the zero in the State/PfxRcd column. This output indicates the BGP session is established (Up/Down shows 6 minutes) but the remote router in AS 65002 is failing to advertise VPNv4 prefixes, which could be due to missing VRF configuration, no network statements, or a route-target mismatch on the VPNv4 address family. On the Cisco CCNP ENARSI 300-410 exam, this scenario tests your ability to interpret the `show bgp vpnv4 unicast all summary` command and distinguish between a session being up and prefixes actually being exchanged—a common trap where engineers assume a working session means working routes. Remember that the “PfxRcd” column is your first diagnostic clue; if it shows zero while the neighbor is up, the issue lies in the sending router’s BGP configuration or the VPNv4 address family activation. A useful memory tip: “Up is not enough—check the count of prefixes received.”
300-410 MPLS L3VPN Practice Question
This 300-410 practice question tests your understanding of mpls l3vpn. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
A network engineer runs the following command on Router PE4:
PE4# show bgp vpnv4 unicast all summary
BGP router identifier 10.0.0.4, local AS number 65001
BGP table version is 25, main routing table version 25
5 network prefixes using 640 bytes of memory
5 path entries using 400 bytes of memory
3/3 BGP path/bestpath attribute entries using 360 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1424 total bytes of memory
BGP activity 15/10 prefixes, 20/15 paths, scan interval 60 secs
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Neighbor 10.0.0.6 is not sending any prefixes.
The BGP summary shows two neighbors: 10.0.0.5 (AS 65001) with 5 prefixes received, and 10.0.0.6 (AS 65002) with 0 prefixes received. The neighbor 10.0.0.6 has been up for 6 minutes but has not sent any prefixes. This indicates a problem with prefix advertisement from that neighbor.
Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Neighbor 10.0.0.5 is not exchanging prefixes.
Why it's wrong here
It has received 5 prefixes, so exchange is happening.
✓
Neighbor 10.0.0.6 is not sending any prefixes.
Why this is correct
The 'State/PfxRcd' column shows 0 for 10.0.0.6, indicating no prefixes received.
Both show an Up/Down time, so they are established.
✗
The BGP table is empty.
Why it's wrong here
The output shows 5 network prefixes, so the table is not empty.
Common exam traps
Common exam trap: OSPF can fail even when IP connectivity looks correct
OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.
Trap categories for this question
Command / output trap
Both show an Up/Down time, so they are established.
Detailed technical explanation
How to think about this question
OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.
KKey Concepts to Remember
OSPF neighbours must agree on key parameters.
Router ID selection can affect neighbour relationships and LSDB output.
OSPF cost influences the preferred path.
A route can appear in OSPF information but not become the installed route.
TExam Day Tips
→Check area mismatch first when OSPF adjacency fails.
→Review passive interfaces when a network is advertised but no neighbour forms.
→Use show ip ospf neighbor and show ip route clues carefully.
Key takeaway
OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 300-410 question in full detail.
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 300-410 OSPF questions on adjacency and route selection.
MPLS L3VPN — This question tests MPLS L3VPN — OSPF neighbours must agree on key parameters..
What is the correct answer to this question?
The correct answer is: Neighbor 10.0.0.6 is not sending any prefixes. — The BGP summary shows two neighbors: 10.0.0.5 (AS 65001) with 5 prefixes received, and 10.0.0.6 (AS 65002) with 0 prefixes received. The neighbor 10.0.0.6 has been up for 6 minutes but has not sent any prefixes. This indicates a problem with prefix advertisement from that neighbor.
What should I do if I get this 300-410 question wrong?
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 300-410 OSPF questions on adjacency and route selection.
What is the key concept behind this question?
OSPF neighbours must agree on key parameters.
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 →
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.
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.
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.
Sign in to join the discussion.