Configuring Preferred VPN Connections for AWS and On-Premise Locations

Configuring Preferred VPN Connections

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Question

You have 2 VPN connections established between AWS and your on-premise location.

You need to ensure that one VPN is preferred over the other. Which of the following configurations can allow you to do this?

Answers

Explanations

Click on the arrows to vote for the correct answer

A. B. C. D.

Answer -A.

The AWS Documentation mentions the following.

AWS will use the more specific routes to send traffic to the appropriate data center, and will fail back to the other data center following the summarized route if the more specific route becomes temporarily unavailable.

For more information on high availability for network connections please see the below link:

https://aws.amazon.com/answers/networking/aws-multiple-data-center-ha-network-connectivity/

To prefer one VPN connection over another between AWS and your on-premises location, you can use the BGP (Border Gateway Protocol) protocol. BGP is a routing protocol that allows you to exchange routing information between different networks.

BGP can use different criteria to choose the best path for traffic, including the length of the AS-path, the origin of the route, the next-hop router, and the weight of the route. In this scenario, you can use the BGP priority attribute to prefer one VPN connection over another.

However, AWS does not support BGP priority as a configuration option. Therefore, options C and D are not valid.

The most common method to control the preferred VPN connection is by using more specific routes. You can configure your on-premises router to advertise more specific routes to AWS over the preferred VPN connection. More specific routes will take precedence over less specific routes, so traffic will be routed over the preferred VPN connection.

For example, if your on-premises network uses the CIDR block 10.0.0.0/16, you can configure your on-premises router to advertise a more specific route for a subset of that CIDR block, such as 10.0.1.0/24, over the preferred VPN connection. AWS will receive both routes, but it will choose the more specific route as the preferred path for traffic destined for 10.0.1.0/24.

Therefore, the correct answer is A: Use more specific routes.