ANS-C01 Network Design Practice Question
A company runs a critical application on Amazon EC2 instances in a VPC. The application receives data from an on-premises data center over an AWS Direct Connect connection. The company wants to add redundant connectivity using a VPN connection over the internet. They need to ensure that traffic from on-premises to AWS uses the Direct Connect connection when it is healthy, and only fails over to the VPN if Direct Connect fails. Which configuration achieves this?
⚠ Common exam trap
The ANS-C01 exam often tests the misconception that AS_PATH prepending or local preference adjustments alone can force primary path selection, but the trap here is that candidates overlook the critical role of prefix specificity in BGP path selection, which takes precedence over MED, AS_PATH, and local preference when prefixes differ.
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
✓
Advertise a more specific prefix over Direct Connect and a less specific prefix over VPN, and set a higher MED value on the VPN routes.
Advertising a more specific prefix (e.g., /24) over Direct Connect and a less specific prefix (e.g., /20) over VPN, combined with a higher MED value on the VPN routes, ensures that the Direct Connect path is preferred when healthy. BGP selects the most specific prefix first, and if prefixes are identical, lower MED is preferred; here, the more specific prefix over Direct Connect wins, and the higher MED on VPN acts as a tie-breaker for any overlapping less specific routes, guaranteeing failover only when Direct Connect is unavailable.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Advertise a more specific prefix over Direct Connect and a less specific prefix over VPN, and set a higher MED value on the VPN routes.
Why this is correct
BGP prefers more specific prefixes. Higher MED on VPN makes Direct Connect routes preferred when both are available.
- ✗
Advertise the same prefix over both connections but prepend AS_PATH multiple times on the Direct Connect routes.
Why it's wrong here
Longer AS_PATH makes a route less preferred, so this would prefer VPN over Direct Connect.
- ✗
Set a higher BGP weight on the VPN routes.
Why it's wrong here
Higher weight makes a route more preferred, so this would prefer VPN.
- ✗
Set a lower BGP local preference on the Direct Connect routes.
Why it's wrong here
Lower local preference makes a route less preferred, so this would prefer VPN.
Go deeper
Related to this question
About these practice questions
One of 1,621 original ANS-C01 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
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.