Question 8 of 1,705
Network DesignhardMultiple ChoiceObjective-mapped

ANS-C01 AWS Transit Gateway 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. A key principle to apply: aWS Transit Gateway. 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.

An enterprise is migrating a critical application to AWS. The application requires low latency (under 5 ms) between two EC2 instances that are in different VPCs in the same region. The company also needs to ensure that traffic is encrypted in transit and that the connection is highly available. Which design should be used?

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

Configure VPC Peering and use an AWS Transit Gateway with VPN attachments

Option B is the closest correct design because AWS Transit Gateway with VPN attachments provides encrypted IPsec tunnels between VPCs, ensuring confidentiality in transit. The VPN attachments are highly available with multiple tunnels, and traffic stays within the AWS backbone, meeting the sub-5 ms latency requirement within the same region. Although the option mentions VPC Peering, it is redundant—Transit Gateway alone connects the VPCs without needing peering. The core components (Transit Gateway + VPN) satisfy both latency and encryption. Option A (Direct Connect) is for on-premises connectivity, not VPC-to-VPC. Option C (PrivateLink) is for accessing services via endpoints, not for VPC-to-VPC routing. Option D (Site-to-Site VPN) traverses the internet, introducing latency that fails the 5 ms requirement.

Key principle: AWS Transit Gateway

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Use an AWS Direct Connect connection between the VPCs

    Why it's wrong here

    Direct Connect is designed for dedicated on-premises connectivity, not VPC-to-VPC, and does not inherently encrypt traffic.

  • Configure VPC Peering and use an AWS Transit Gateway with VPN attachments

    Why this is correct

    Correct because Transit Gateway with VPN attachments provides encrypted, low-latency connectivity between VPCs within the same region, meeting the 5 ms requirement. The mention of VPC Peering is unnecessary but does not invalidate the core solution.

    Related concept

    AWS Transit Gateway

  • Use VPC endpoints with PrivateLink

    Why it's wrong here

    PrivateLink allows access to services via VPC endpoints, but does not route traffic between entire VPCs and does not inherently encrypt all traffic.

  • Establish an AWS Site-to-Site VPN between the VPCs

    Why it's wrong here

    Site-to-Site VPN traverses the public internet, adding latency that likely exceeds 5 ms, and it is not optimized for VPC-to-VPC connectivity.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap is that candidates may think VPC Peering is required with Transit Gateway, but it is not—Transit Gateway inherently connects VPCs. The key is recognizing that VPN attachments provide the encryption, and Transit Gateway ensures low latency within the region.

Detailed technical explanation

How to think about this question

AWS Transit Gateway uses a hub-and-spoke model that allows VPCs to communicate through a central router, enabling encrypted VPN attachments with IPsec (using AES-256 and SHA-256) and automatic failover between tunnels. The sub-5 ms latency is achievable because traffic between VPCs in the same region traverses the AWS global backbone, which typically has single-digit millisecond latency. In practice, this design is often used for multi-account architectures where compliance requires encryption in transit and high availability, such as financial services applications.

KKey Concepts to Remember

  • AWS Transit Gateway
  • VPN Attachment
  • VPC Peering

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

AWS Transit Gateway

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.

Quick reference

VPN Protocol Comparison

ProtocolPortEncryptionAuthenticationUse Case
IKEv2 / IPsecUDP 500 / 4500AES-256Certificates / PSKSite-to-site & remote access
SSL / TLS VPNTCP 443TLS 1.3Certificates / MFAClientless remote access
L2TP / IPsecUDP 1701AES (IPsec)PSK / CertificatesLegacy remote access
WireGuardUDP 51820ChaCha20Public keysModern high-performance VPN
PPTPTCP 1723MPPE (weak)MS-CHAPv2Legacy — avoid in production

PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.

What to study next

Got this wrong? Here's your next step.

Review aWS Transit Gateway, then practise related ANS-C01 questions on the same topic to reinforce the concept.

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FAQ

Questions learners often ask

What does this ANS-C01 question test?

Network Design — This question tests Network Design — AWS Transit Gateway.

What is the correct answer to this question?

The correct answer is: Configure VPC Peering and use an AWS Transit Gateway with VPN attachments — Option B is the closest correct design because AWS Transit Gateway with VPN attachments provides encrypted IPsec tunnels between VPCs, ensuring confidentiality in transit. The VPN attachments are highly available with multiple tunnels, and traffic stays within the AWS backbone, meeting the sub-5 ms latency requirement within the same region. Although the option mentions VPC Peering, it is redundant—Transit Gateway alone connects the VPCs without needing peering. The core components (Transit Gateway + VPN) satisfy both latency and encryption. Option A (Direct Connect) is for on-premises connectivity, not VPC-to-VPC. Option C (PrivateLink) is for accessing services via endpoints, not for VPC-to-VPC routing. Option D (Site-to-Site VPN) traverses the internet, introducing latency that fails the 5 ms requirement.

What should I do if I get this ANS-C01 question wrong?

Review aWS Transit Gateway, then practise related ANS-C01 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

AWS Transit Gateway

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Last reviewed: Jun 24, 2026

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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.