- A
Create a virtual private gateway with a Direct Connect private virtual interface. Additionally, create a separate VPN connection directly to the VPC. Set longer AS path for the Direct Connect routes.
Why wrong: Longer AS path makes VPN preferred, which is opposite of the requirement.
- B
Create a virtual private gateway and establish both a Direct Connect private virtual interface and a VPN connection. Use BGP with equal AS path lengths to enable ECMP.
Why wrong: ECMP distributes traffic across both connections, not failover.
- C
Create a virtual private gateway and attach a Direct Connect private virtual interface. For failover, add a static route in the VPC route table pointing to the VPN connection.
Why wrong: Static routes do not provide automatic failover and would require manual intervention.
- D
Create a virtual private gateway attached to the VPC. Establish a Direct Connect private virtual interface and a VPN connection to the virtual private gateway. Configure BGP on both connections and use a shorter AS path for the Direct Connect routes.
The shorter AS path makes Direct Connect preferred, and BGP provides automatic failover.
Quick Answer
The answer is to create a virtual private gateway attached to the VPC, establish both a Direct Connect private virtual interface and a VPN connection to that gateway, and configure BGP on both connections while advertising a shorter AS path for the Direct Connect routes. This works because BGP path selection prefers the route with the shortest AS path length; by prepending fewer AS numbers on the Direct Connect side, the on-premises router and VPC will always choose that path when it is available, and the VPN routes (with a longer, prepended AS path) automatically take over only when the Direct Connect BGP session drops. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this scenario tests your understanding of BGP attributes for hybrid network failover, and a common trap is assuming static routes or a single connection type can provide seamless failover without BGP path manipulation. Remember the key: shorter AS path wins, so Direct Connect gets the shorter prepend, and the VPN gets the longer prepend for backup.
ANS-C01 Network Design Practice Question
This ANS-C01 practice question tests your understanding of network design. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 is designing a hybrid network where an Amazon VPC is connected to an on-premises data center via AWS Direct Connect and a VPN backup. They have a VPC with CIDR 10.0.0.0/16 and on-premises CIDR 192.168.0.0/16. They want to ensure that all traffic between the VPC and on-premises uses the Direct Connect connection when it is available, and automatically fails over to the VPN if Direct Connect fails. What should they do?
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
Create a virtual private gateway attached to the VPC. Establish a Direct Connect private virtual interface and a VPN connection to the virtual private gateway. Configure BGP on both connections and use a shorter AS path for the Direct Connect routes.
Option D is correct because it uses a virtual private gateway (VGW) for both the Direct Connect private virtual interface and the VPN connection, and configures BGP on both. By advertising a shorter AS path (e.g., prepending fewer AS numbers) for the Direct Connect routes, the VPC and on-premises routers prefer the Direct Connect path when available. If Direct Connect fails, the BGP session drops, and the VPN routes (with a longer AS path) become active, providing automatic failover.
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.
- ✗
Create a virtual private gateway with a Direct Connect private virtual interface. Additionally, create a separate VPN connection directly to the VPC. Set longer AS path for the Direct Connect routes.
Why it's wrong here
Longer AS path makes VPN preferred, which is opposite of the requirement.
- ✗
Create a virtual private gateway and establish both a Direct Connect private virtual interface and a VPN connection. Use BGP with equal AS path lengths to enable ECMP.
Why it's wrong here
ECMP distributes traffic across both connections, not failover.
- ✗
Create a virtual private gateway and attach a Direct Connect private virtual interface. For failover, add a static route in the VPC route table pointing to the VPN connection.
Why it's wrong here
Static routes do not provide automatic failover and would require manual intervention.
- ✓
Create a virtual private gateway attached to the VPC. Establish a Direct Connect private virtual interface and a VPN connection to the virtual private gateway. Configure BGP on both connections and use a shorter AS path for the Direct Connect routes.
Why this is correct
The shorter AS path makes Direct Connect preferred, and BGP provides automatic failover.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
AWS often tests the misconception that you can simply attach a Direct Connect private virtual interface to a VGW and then add a static route for failover, but this ignores the need for BGP-based dynamic failover and the risk of route conflicts or black-holing when both paths are active.
Detailed technical explanation
How to think about this question
BGP path selection uses AS path length as one of the tie-breakers; a shorter AS path is preferred. By prepending additional AS numbers to the routes advertised over the VPN, the Direct Connect path remains the primary. Under the hood, the VGW maintains separate BGP sessions for the Direct Connect and VPN connections; when the Direct Connect BGP session goes down (e.g., due to link failure), the VGW withdraws those routes, and the VPN routes (with longer AS path) become the best path. In real-world scenarios, you can also use BGP communities or MED attributes for finer control, but AS path prepending is the simplest and most common method.
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 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.
What to study next
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FAQ
Questions learners often ask
What does this ANS-C01 question test?
Network Design — This question tests Network Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create a virtual private gateway attached to the VPC. Establish a Direct Connect private virtual interface and a VPN connection to the virtual private gateway. Configure BGP on both connections and use a shorter AS path for the Direct Connect routes. — Option D is correct because it uses a virtual private gateway (VGW) for both the Direct Connect private virtual interface and the VPN connection, and configures BGP on both. By advertising a shorter AS path (e.g., prepending fewer AS numbers) for the Direct Connect routes, the VPC and on-premises routers prefer the Direct Connect path when available. If Direct Connect fails, the BGP session drops, and the VPN routes (with a longer AS path) become active, providing automatic failover.
What should I do if I get this ANS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
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.
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