ANS-C01 Network Design Practice Question
A company is migrating to AWS and needs to connect its on-premises data center to multiple VPCs across several AWS regions. The on-premises network uses BGP and requires high availability with sub-second failover. The solution must be cost-effective and support traffic segmentation. Which design meets these requirements?
⚠ Common exam trap
It's easy for candidates to assume Transit Gateway (Option C) is always the best choice for multi-VPC connectivity, but fail to recognize that the on-premises VPN attachment still relies on internet-based VPN, which cannot meet the sub-second failover requirement, whereas Direct Connect with BFD provides deterministic fast failover.
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
✓
Order an AWS Direct Connect connection and create multiple virtual interfaces, each connecting to a different VPC in different regions. Use BGP with Bidirectional Forwarding Detection (BFD) for fast failover.
AWS Direct Connect with multiple virtual interfaces (VIFs) provides dedicated, low-latency connectivity to multiple VPCs across different regions. Using BGP with Bidirectional Forwarding Detection (BFD) enables sub-second failover detection (typically 150ms or less), meeting the high availability requirement. This design is cost-effective compared to multiple VPN connections and supports traffic segmentation through separate VIFs or VLANs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Set up a Site-to-Site VPN connection between on-premises and each VPC using a VPN appliance on AWS.
Why it's wrong here
Wrong: VPN over internet cannot guarantee sub-second failover.
- ✓
Order an AWS Direct Connect connection and create multiple virtual interfaces, each connecting to a different VPC in different regions. Use BGP with Bidirectional Forwarding Detection (BFD) for fast failover.
Why this is correct
Correct: Direct Connect provides stable latency, and BFD enables sub-second failover.
- ✗
Use AWS Transit Gateway with inter-region peering and attach VPN connections from on-premises to a central Transit Gateway.
Why it's wrong here
Wrong: Transit Gateway inter-region peering does not support on-premises connections.
- ✗
Use a combination of Direct Connect and VPN as a backup, and route all traffic through a single VPC that acts as a transit hub.
Why it's wrong here
Wrong: Single point of failure and does not scale.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 practice question is part of Courseiva's free Amazon Web Services 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 ANS-C01 exam.