PCNE Practice Question: Managing, Monitoring, and Optimising Network Operations
An engineer is troubleshooting asymmetric routing between two VPCs connected via VPC peering. They notice that return traffic takes a different path. What is a common cause of asymmetric routing in this scenario?
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
✓
One VPC has a more specific route that overrides the peering route
If both VPCs have routes to each other via different paths (e.g., one using peering and the other using a VPN), traffic may take asymmetric paths. VPC peering does not support transitive routing, but misconfigured routes can cause asymmetry.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
VPC Flow Logs are not enabled
Why it's wrong here
Flow Logs are monitoring, not routing.
- ✓
One VPC has a more specific route that overrides the peering route
Why this is correct
Correct: If one VPC has a more specific route (e.g., via VPN) for the other VPC's subnet, return traffic may go that way, causing asymmetry.
- ✗
The MTU is mismatched between the VPCs
Why it's wrong here
MTU mismatch causes drops, not routing asymmetry.
- ✗
Firewall rules are blocking the return traffic
Why it's wrong here
Firewall rules would drop traffic, not cause asymmetry.
Quick reference
Asymmetric Encryption Algorithm Comparison
| Algorithm | Key Exchange | Signatures | Equivalent Security Key | Notes |
|---|---|---|---|---|
| RSA-3072 | Yes | Yes | 128-bit | Widely deployed; slow for bulk data |
| ECDSA P-256 | No | Yes | 128-bit | Fast signatures; standard TLS certs |
| ECDH / ECDHE | Yes | No | 128-bit | Perfect forward secrecy in TLS 1.3 |
| DH / DHE | Yes | No | 128-bit (3072-bit key) | Replaced by ECDHE in modern TLS |
| Ed25519 | No | Yes | ~128-bit | SSH keys, modern PKI |
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JA
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.