- A
The on-premises routers need static routes pointing to the Google Cloud VPC for inter-site traffic.
Why wrong: NCC handles dynamic routing.
- B
The VPN spokes do not have custom dynamic route exchange enabled, so routes from Site A are not advertised to Site B.
NCC requires route exchange to be enabled on spokes to propagate routes.
- C
Network Connectivity Center does not support Cloud VPN as a spoke type.
Why wrong: NCC supports VPN as a spoke.
- D
The NCC hub must be in the same VPC network as the sites' VPCs.
Why wrong: NCC works across VPCs; it's a global resource.
Question 654 of 1,000
hardMultiple ChoiceObjective-mapped
Network Connectivity Center Spoke Route Exchange
This PCNE practice question tests your understanding of network connectivity center (ncc) hub. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: network Connectivity Center (NCC) hub. 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.
Your company uses Network Connectivity Center (NCC) to manage multiple on-premises sites connected via Cloud VPN and Partner Interconnect. You create a NCC hub and attach spokes (VPN tunnels and VLAN attachments). Traffic between two on-premises sites (Site A and Site B) should flow through Google Cloud. However, traffic is not passing between the sites. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Quick Answer
The answer is that the VPN spokes do not have custom dynamic route exchange enabled, so routes from Site A are not advertised to Site B. This is the most likely cause because Network Connectivity Center relies on spokes to propagate routes between on-premises sites, and by default, VPN tunnel spokes do not advertise custom dynamic routes unless explicitly configured. Without enabling custom dynamic route exchange, the NCC hub cannot distribute learned routes from one spoke to another, breaking the intended path through Google Cloud. On the Google Professional Cloud Network Engineer exam, this scenario tests your understanding of NCC spoke route exchange mechanics, often appearing as a trap where candidates assume VPN spokes automatically share routes like VLAN attachments do. A common memory tip is to remember that VPN spokes are “silent by default”—you must flip the custom dynamic route exchange switch to make them talk.
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 VPN spokes do not have custom dynamic route exchange enabled, so routes from Site A are not advertised to Site B.
The most likely cause is that custom dynamic route exchange is not enabled on the VPN spokes. By default, NCC does not advertise routes between VPN spokes unless you explicitly enable custom dynamic route exchange. Without this, routes from Site A are not propagated to Site B, preventing inter-site traffic through Google Cloud. Option A is incorrect because NCC uses dynamic routing, so static routes to the VPC are unnecessary. Option C is incorrect because NCC supports Cloud VPN as a spoke type. Option D is incorrect because the NCC hub is a global resource and does not need to reside in the same VPC as the sites' VPCs.
Key principle: Network Connectivity Center (NCC) hub
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 on-premises routers need static routes pointing to the Google Cloud VPC for inter-site traffic.
Why it's wrong here
NCC handles dynamic routing.
- ✓
The VPN spokes do not have custom dynamic route exchange enabled, so routes from Site A are not advertised to Site B.
Why this is correct
NCC requires route exchange to be enabled on spokes to propagate routes.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Network Connectivity Center (NCC) hub
- ✗
Network Connectivity Center does not support Cloud VPN as a spoke type.
Why it's wrong here
NCC supports VPN as a spoke.
- ✗
The NCC hub must be in the same VPC network as the sites' VPCs.
Why it's wrong here
NCC works across VPCs; it's a global resource.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Network Connectivity Center (NCC) hub
- VPN spoke
- Custom dynamic route exchange
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Network Connectivity Center (NCC) hub
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
Visual reference
What to study next
Got this wrong? Here's your next step.
Review network Connectivity Center (NCC) hub, then practise related PCNE questions on the same topic to reinforce the concept.
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FAQ
Questions learners often ask
What does this PCNE question test?
Network Connectivity Center (NCC) hub
What is the correct answer to this question?
The correct answer is: The VPN spokes do not have custom dynamic route exchange enabled, so routes from Site A are not advertised to Site B. — The most likely cause is that custom dynamic route exchange is not enabled on the VPN spokes. By default, NCC does not advertise routes between VPN spokes unless you explicitly enable custom dynamic route exchange. Without this, routes from Site A are not propagated to Site B, preventing inter-site traffic through Google Cloud. Option A is incorrect because NCC uses dynamic routing, so static routes to the VPC are unnecessary. Option C is incorrect because NCC supports Cloud VPN as a spoke type. Option D is incorrect because the NCC hub is a global resource and does not need to reside in the same VPC as the sites' VPCs.
What should I do if I get this PCNE question wrong?
Review network Connectivity Center (NCC) hub, then practise related PCNE questions on the same topic to reinforce the concept.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Network Connectivity Center (NCC) hub
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Last reviewed: Jun 24, 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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