- A
MED (metric)
Why wrong: MED (Multi-Exit Discriminator) is used to influence inbound traffic to the AS that advertises the route. In this scenario, it would influence on-premises to GCP traffic, not GCP to on-premises as required.
- B
AS path prepending
Why wrong: AS path prepending is used to make a path appear longer, thereby making it less preferred for inbound traffic. It does not directly influence outbound path selection from GCP.
- C
Weight attribute
Why wrong: Weight is a Cisco-proprietary attribute that influences outbound path selection, but it is not supported on Google Cloud Router (or in standard BGP). Google Cloud Router uses local preference for this purpose.
- D
Local preference
Local preference is a well-known BGP attribute that is used to prefer one path over another for outbound traffic. By setting a higher local preference on the primary Cloud Router for routes received from the primary attachment, the Cloud Router will prefer that path for traffic from GCP to on-premises.
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.
You are configuring a Cloud Router for a Dedicated Interconnect VLAN attachment. The on-premises BGP AS number is 65001. You want to ensure that traffic from Google Cloud to on-premises prefers the primary attachment over the backup. Which BGP attribute should you configure on the primary Cloud Router to achieve this?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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
Local preference
To influence traffic from Google Cloud to on-premises (outbound from GCP), you need to affect the path selection on the Cloud Router for received routes. Local preference is a well-known BGP attribute used to prefer one path over another when multiple paths are received to the same destination. By setting a higher local preference on the primary Cloud Router for routes received from the primary attachment, the Cloud Router will prefer that path for outbound traffic. MED influences inbound traffic to the advertiser (on-prem to GCP), not outbound from GCP.
Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
MED (metric)
Why it's wrong here
MED (Multi-Exit Discriminator) is used to influence inbound traffic to the AS that advertises the route. In this scenario, it would influence on-premises to GCP traffic, not GCP to on-premises as required.
- ✗
AS path prepending
Why it's wrong here
AS path prepending is used to make a path appear longer, thereby making it less preferred for inbound traffic. It does not directly influence outbound path selection from GCP.
- ✗
Weight attribute
Why it's wrong here
Weight is a Cisco-proprietary attribute that influences outbound path selection, but it is not supported on Google Cloud Router (or in standard BGP). Google Cloud Router uses local preference for this purpose.
- ✓
Local preference
Why this is correct
Local preference is a well-known BGP attribute that is used to prefer one path over another for outbound traffic. By setting a higher local preference on the primary Cloud Router for routes received from the primary attachment, the Cloud Router will prefer that path for traffic from GCP to on-premises.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Access ports place end devices into a single VLAN.
Common exam traps
Common exam trap: an active trunk can still block the VLAN you need
A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.
Trap categories for this question
Scenario analysis trap
MED (Multi-Exit Discriminator) is used to influence inbound traffic to the AS that advertises the route. In this scenario, it would influence on-premises to GCP traffic, not GCP to on-premises as required.
Detailed technical explanation
How to think about this question
VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.
KKey Concepts to Remember
- Access ports place end devices into a single VLAN.
- Trunk ports carry multiple VLANs between switches.
- Allowed VLAN lists decide which VLANs can cross a trunk.
- Native VLAN mismatch can create confusing symptoms.
TExam Day Tips
- Use show vlan brief to verify access VLANs.
- Use show interfaces trunk to verify trunk state and allowed VLANs.
- Do not treat every same-VLAN issue as a routing problem.
Key takeaway
A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
Visual reference
What to study next
Got this wrong? Here's your next step.
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related PCNE questions on switching, trunking, and access-port configuration.
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Implementing Hybrid Interconnectivity — study guide chapter
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FAQ
Questions learners often ask
What does this PCNE question test?
Implementing Hybrid Interconnectivity — This question tests Implementing Hybrid Interconnectivity — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: Local preference — To influence traffic from Google Cloud to on-premises (outbound from GCP), you need to affect the path selection on the Cloud Router for received routes. Local preference is a well-known BGP attribute used to prefer one path over another when multiple paths are received to the same destination. By setting a higher local preference on the primary Cloud Router for routes received from the primary attachment, the Cloud Router will prefer that path for outbound traffic. MED influences inbound traffic to the advertiser (on-prem to GCP), not outbound from GCP.
What should I do if I get this PCNE question wrong?
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related PCNE questions on switching, trunking, and access-port configuration.
Are there clue words in this question I should notice?
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
What is the key concept behind this question?
Access ports place end devices into a single VLAN.
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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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