Amazon ANS-C01 Exam - Topic 2 Question 56 Discussion

Actual exam question for Amazon's ANS-C01 exam

Question #: 56
Topic #: 2

An international company wants to implement a multi-site hybrid infrastructure. The company wants to deploy its cloud computing resources on AWS in the us-east-1 Region and in the eu-west-2 Region, and in on-premises data centers in the United States (US) and in the United Kingdom (UK). The data centers are connected to each other by a private WAN connection. IP routing information is exchanged dynamically through BGP. The company wants to have two AWS Direct Connect connections, one each in the US and the UK.

The company expects to have 15 VPCs in each Region with CIDR blocks that do not overlap with each other or with CIDR blocks of the on-premises environment. The VPC CIDR blocks are planned so that the prefix aggregation can be performed both on a Regional level and across the entire AWS environment. The company will deploy a transit gateway in each Region to connect the VPCs. A network engineer plans to use a Direct Connect gateway in each Region. A transit VIF will attach the Direct Connect gateway in each Region to the transit gateway in that Region. The transit gateways will be peered with each other.

The network engineer wants to ensure that traffic follows the shortest geographical path from source to destination. Traffic between the on-premises data centers and AWS must travel across a local Direct Connect connection. Traffic between the US data center and eu-west-2 and traffic between the UK data center and us-east-1 must use the private WAN connection to reach the Direct Connect connection to the appropriate Region when the Direct Connect connection is available. The network must be resilient to failures in either the private WAN connection or with the Direct Connect connections. The network also must reroute traffic automatically in the event of any failure.

How should the network engineer configure the transit VIF associations on the Direct Connect gateways to meet these requirements?

AAdvertise only the aggregate route for the company's entire AWS environment.

BAdvertise VPC-specific CIDR prefixes from only the local Region. Additionally, advertise the aggregate route for the company's entire AWS environment.

CAdvertise all the specific VPC CIDR blocks from both Regions.

DAdvertise both Regional aggregate prefixes. Configure custom BGP communities on the routes advertised toward the data center.

Show Suggested Answer

Suggested Answer: B

by Trina at Oct 13, 2025, 07:33 AM

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Jovita

9 days ago

I'm leaning towards A. Keeping it simple with just the aggregate route.

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Wade

14 days ago

I agree, B seems to cover both local and aggregate routes well.

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Hollis

19 days ago

This question is tricky! I think option B makes sense.

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Derick

24 days ago

Are we sure the private WAN can handle all that traffic? Just saying...

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Jestine

29 days ago

Totally agree with B, it balances specificity and simplicity.

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Nickolas

1 month ago

Wait, why would you want to advertise all VPC CIDR blocks? Seems excessive.

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Azzie

1 month ago

I think option B makes the most sense here.

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Jutta

1 month ago

Sounds like a solid multi-site setup!

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Ruthann

2 months ago

I bet the network engineer is just hoping the exam question doesn't ask them to configure BGP communities in binary.

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Glenna

2 months ago

D is an interesting approach, but the custom BGP communities might be overkill for this scenario.

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Goldie

2 months ago

C is too broad, advertising all VPC CIDR blocks from both Regions could get messy and complex.

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Lazaro

2 months ago

I agree, Option B allows for both regional and global aggregation while still maintaining the necessary routing information.

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Shantay

2 months ago

Option B seems like the most logical choice to ensure traffic follows the shortest geographical path.

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Sherrell

3 months ago

Option D could work too. Custom BGP communities might help with routing.

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Lamonica

3 months ago

This is a complex scenario, but I feel confident I can work through it. The requirements around resiliency and automatic rerouting in the event of failures are key. I think Option D is the best approach, as it allows me to control the BGP communities to influence the traffic flow.

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Alexis

4 months ago

Okay, I think I've got a handle on this. The goal is to optimize the routing to use the local Direct Connect connections whenever possible, and fall back to the private WAN connection when needed. Option B looks like the way to go - advertise the VPC-specific prefixes from the local Region, and the aggregate route for the whole environment.

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Stephania

4 months ago

Hmm, this is a tricky one. I think the key is figuring out how to configure the transit VIF associations to ensure the traffic follows the shortest geographical path while also providing redundancy. Option D seems promising, but I'll need to double-check the details on the BGP communities.

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Larae

4 months ago

I'm a bit confused by the level of detail in this question. It seems like there are a lot of moving parts to consider, like the transit gateways, Direct Connect gateways, and BGP configurations. I'll need to carefully read through the requirements and think through the implications of each option.

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Gilberto

3 months ago

Right? The BGP configurations alone are tricky.

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Linn

3 months ago

This setup sounds complex! So many components to manage.

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Loren

3 months ago

Agreed! Keeping it local with aggregate routes is key.

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Mozell

4 months ago

I think option D could be a good choice since it mentions custom BGP communities, which we learned can help with traffic management across regions.

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Albina

4 months ago

I'm a bit confused about whether we need to advertise all specific VPC CIDR blocks. It feels like that could lead to too much complexity.

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Avery

5 months ago

This question seems similar to one we practiced about VPC peering and route propagation. I think option B makes sense because it balances local and aggregate routes.

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Isadora

5 months ago

I remember we discussed the importance of aggregate routes in class, but I'm not sure if we should only advertise the aggregate for the entire environment or include specific VPC CIDR prefixes too.

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