- A
Set different local preference values on the Google Cloud Router
Why wrong: Local preference is used within an AS, not between ASes, and would not enable ECMP.
- B
Configure the on-premises router to enable ECMP for the BGP routes
ECMP on the on-premises router allows it to use both paths equally.
- C
Use AS path prepending on one connection to make it less preferred
Why wrong: AS path prepending is used for traffic engineering, not for active-active load sharing.
- D
Assign different MED values to each connection to influence preference
Why wrong: Different MED values would make one path preferred, not active-active.
Question 89 of 982
PCNE Implementing Hybrid Interconnectivity Practice Question
This PCNE practice question tests your understanding of implementing hybrid interconnectivity. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 company has two Dedicated Interconnect connections from different metro areas to Google Cloud. Both connections are active and they want to use both simultaneously for load balancing traffic. They have configured two VLAN attachments each with a Cloud Router and BGP sessions. How should they configure BGP to achieve active-active load sharing?
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 the on-premises router to enable ECMP for the BGP routes
Equal-cost multipath (ECMP) requires that the routes from both connections have the same next-hop attribute and are learned via different BGP sessions. By default, Cloud Router advertises the same routes with the same MED and AS path. To enable ECMP, the on-premises router must be configured to accept multiple equal-cost paths. The Cloud Router will automatically advertise routes with identical attributes when using separate VLAN attachments, and the on-premises router can then load balance.
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.
- ✗
Set different local preference values on the Google Cloud Router
Why it's wrong here
Local preference is used within an AS, not between ASes, and would not enable ECMP.
- ✓
Configure the on-premises router to enable ECMP for the BGP routes
Why this is correct
ECMP on the on-premises router allows it to use both paths equally.
Related concept
OSPF neighbours must agree on key parameters.
- ✗
Use AS path prepending on one connection to make it less preferred
Why it's wrong here
AS path prepending is used for traffic engineering, not for active-active load sharing.
- ✗
Assign different MED values to each connection to influence preference
Why it's wrong here
Different MED values would make one path preferred, not active-active.
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.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
Visual reference
What to study next
Got this wrong? Here's your next step.
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 PCNE OSPF questions on adjacency and route selection.
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Implementing Hybrid Interconnectivity — study guide chapter
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Implementing Hybrid Interconnectivity practice questions
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FAQ
Questions learners often ask
What does this PCNE question test?
Implementing Hybrid Interconnectivity — This question tests Implementing Hybrid Interconnectivity — OSPF neighbours must agree on key parameters..
What is the correct answer to this question?
The correct answer is: Configure the on-premises router to enable ECMP for the BGP routes — Equal-cost multipath (ECMP) requires that the routes from both connections have the same next-hop attribute and are learned via different BGP sessions. By default, Cloud Router advertises the same routes with the same MED and AS path. To enable ECMP, the on-premises router must be configured to accept multiple equal-cost paths. The Cloud Router will automatically advertise routes with identical attributes when using separate VLAN attachments, and the on-premises router can then load balance.
What should I do if I get this PCNE 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 PCNE OSPF questions on adjacency and route selection.
What is the key concept behind this question?
OSPF neighbours must agree on key parameters.
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Last reviewed: Jul 4, 2026
This PCNE practice question is part of Courseiva's free Google Cloud 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 PCNE exam.
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