PCNE Configuring Network Services Practice Question
A company has deployed a Global External Application Load Balancer with Premium Tier and enables Cloud CDN. Users in Europe report high latency, while users in the US have good performance. The backend is a regional NEG in us-west1. What is the most likely cause?
⚠ Common exam trap
Google Cloud often tests the misconception that enabling Cloud CDN automatically caches all content, when in reality the origin's cache-control headers dictate cacheability, and 'Cache-Control: private' is a common reason for CDN bypass.
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 origin server is sending 'Cache-Control: private' headers, preventing Cloud CDN from caching.
Cloud CDN cannot cache responses that include a 'Cache-Control: private' header. This header instructs intermediate caches (including CDN nodes) not to store the response, forcing all requests to go to the origin server in us-west1. Users in Europe experience high latency because their requests must traverse the long distance to the US origin, while US users benefit from shorter paths. Enabling Cloud CDN alone does not guarantee caching; the origin must also allow caching by omitting 'private' or setting appropriate 'Cache-Control: public' and 'max-age' directives.
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 load balancer is using Premium Tier, which routes to the nearest backend; the backend is only in us-west1.
Why it's wrong here
Global load balancer does route to the nearest healthy backend, but CDN should cache; latency is due to lack of caching.
- ✗
Cloud CDN is not enabled on the load balancer.
Why it's wrong here
The scenario states Cloud CDN is enabled.
- ✗
The load balancer is using Standard Tier, which does not support global anycast.
Why it's wrong here
The scenario explicitly says Premium Tier is used.
- ✓
The origin server is sending 'Cache-Control: private' headers, preventing Cloud CDN from caching.
Why this is correct
Cloud CDN respects origin cache headers; private or no-store headers prevent caching, so all requests hit the backend.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.