The answer is session affinity set to CLIENT_IP, which forces sticky sessions to a distant backend. This is correct because CLIENT_IP affinity hashes the client’s IP address to a specific backend instance, overriding the global HTTP(S) load balancer’s normal proximity-based or least-latency routing. When a European user is hashed to a backend in us-east1, all their requests are forwarded across the Atlantic, causing high latency even though a healthy backend exists in europe-west1. On the Google Professional Cloud Network Engineer exam, this scenario tests your understanding of how session affinity interacts with global load balancing—a common trap is assuming the load balancer always routes to the nearest region. Remember that affinity creates a “sticky” binding that ignores geographic optimization. Memory tip: “Sticky IP sends you far across the sea; for low latency, let affinity be NONE or COOKIE.”
PCNE Configuring network services Practice Question
This PCNE practice question tests your understanding of configuring network services. 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. 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 a VPC with subnets in us-east1 and europe-west1. They have deployed a global external HTTP(S) load balancer with backend services in both regions. Users in Europe report high latency. 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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Session affinity set to CLIENT_IP, causing sticky sessions to a distant backend
Option D is correct because CLIENT_IP session affinity causes the load balancer to hash the client's IP address to a specific backend instance. If a user in Europe is hashed to a backend in us-east1, all their requests will be forwarded to that distant region, resulting in high latency. This occurs even though a healthy backend exists in europe-west1, because the affinity overrides the load balancer's normal least-latency or proximity-based routing.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Incorrect health check configuration causing backends to be marked unhealthy
Why it's wrong here
Would cause errors, not high latency.
✗
Firewall rules blocking traffic from the load balancer's health check probes
Why it's wrong here
Health checks are separate from user traffic.
✗
The load balancer is not enabled for global access
Session affinity set to CLIENT_IP, causing sticky sessions to a distant backend
Why this is correct
Traffic might be pinned to us-east1 even for European users.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that high latency is always caused by health check or firewall issues, when in fact session affinity can override geographic routing and force traffic to a distant backend.
Detailed technical explanation
How to think about this question
Global external HTTP(S) load balancers use Anycast IP addresses and Google's front-end (GFE) infrastructure to direct traffic to the nearest GFE that has a healthy backend. When session affinity is set to CLIENT_IP, the load balancer generates a hash of the client's IP and maps it to a specific backend instance, bypassing the proximity-based routing. This can cause a user in London to be pinned to a backend in Virginia, adding 70–100 ms of latency due to transatlantic round-trip time, even if a local backend is available.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Configuring network services — This question tests Configuring network services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Session affinity set to CLIENT_IP, causing sticky sessions to a distant backend — Option D is correct because CLIENT_IP session affinity causes the load balancer to hash the client's IP address to a specific backend instance. If a user in Europe is hashed to a backend in us-east1, all their requests will be forwarded to that distant region, resulting in high latency. This occurs even though a healthy backend exists in europe-west1, because the affinity overrides the load balancer's normal least-latency or proximity-based routing.
What should I do if I get this PCNE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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?
Read the scenario before looking for a memorised answer.
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 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.
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.