The answer is to create a Transit Gateway route table and add static routes for each VPC CIDR pointing to the respective attachment. This configuration is correct because a Transit Gateway full mesh VPC configuration requires three core elements: VPC attachments for each network, a route table containing routes that direct traffic between the VPC CIDRs via their specific attachments, and the association of each VPC attachment to that route table. On the AWS Certified Advanced Networking Specialty ANS-C01 exam, this question tests your understanding that a single Transit Gateway route table can serve all attachments for full mesh connectivity, unlike the common trap of assuming separate route tables are mandatory—they are only needed for network isolation. A key memory tip is “one table, all routes, all associations” for full mesh, and remember that VPN attachments are irrelevant for VPC-to-VPC routing through a Transit Gateway.
ANS-C01 Network Design Practice Question
This ANS-C01 practice question tests your understanding of network design. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 has a VPC with an IPv4 CIDR of 10.0.0.0/16. It needs to connect to two other VPCs: VPC B (10.1.0.0/16) and VPC C (10.2.0.0/16). The company wants to use AWS Transit Gateway. Which THREE configurations are required to enable full mesh connectivity between all three VPCs?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Associate each VPC attachment with the Transit Gateway route table.
Options A, B, and C are correct. Transit Gateway requires VPC attachments, route tables with routes to each other's CIDR, and association of attachments to route tables. Option D is wrong because you can create a single route table and associate all attachments; separate route tables are needed for isolation, not required for full mesh. Option E is wrong because a transit gateway does not require a VPN attachment for VPC-to-VPC routing.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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 separate Transit Gateway route tables for each VPC to isolate traffic.
Why it's wrong here
Separate route tables would isolate, not enable full mesh.
✗
Create a VPN attachment to each VPC for encrypted communication.
Why it's wrong here
VPN attachments are for on-premises, not needed for VPC-to-VPC over Transit Gateway.
✓
Associate each VPC attachment with the Transit Gateway route table.
Why this is correct
Association allows the VPC to use the route table.
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related ANS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
Network Design — This question tests Network Design — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Associate each VPC attachment with the Transit Gateway route table. — Options A, B, and C are correct. Transit Gateway requires VPC attachments, route tables with routes to each other's CIDR, and association of attachments to route tables. Option D is wrong because you can create a single route table and associate all attachments; separate route tables are needed for isolation, not required for full mesh. Option E is wrong because a transit gateway does not require a VPN attachment for VPC-to-VPC routing.
What should I do if I get this ANS-C01 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related ANS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.