AWS Direct Connect - How to display VPC Routes Preference

From your router, you can see what is being advertised over BGP to your peer (AWS). However, only accepted routes will show on the TGW route table. Aggregated at the Direct Connect Gateway attachment level. You might involve AWS Support engineer using a support case to take a look on what is being received from your customer router.

Some considerations what can impact your route decision is the selection of your colocation in reference to your main region. Here is a quick guide with some examples: https://repost.aws/knowledge-center/direct-connect-private-transit-interface

Here is useful information on how to implement a hybrid connection architecture with multiple routes and direct connect. You might consider multiple DXG if you want to manage the routes with segregation by the DCGW attachment ID. https://aws.amazon.com/blogs/networking-and-content-delivery/hybrid-cloud-architectures-using-aws-direct-connect-gateway/

Unfortunately, there isn't a direct way to view the specific next-hop Direct Connect for a particular route through the AWS Console. However, you can use some alternative methods to understand and manage route preferences for your Direct Connect connections.

To set up a backup Direct Connect and ensure it's not the preferred route:

1. Use BGP communities: Even though you mentioned not using BGP communities currently, this is an effective way to influence route preference. You can assign different BGP community values to your primary and backup Direct Connect connections. AWS will then use these values to determine route preference.

2. Adjust AS Path: While you currently have the same AS Path for all connections, you can prepend your AS number to the backup Direct Connect route advertisements. This will make the AS Path longer for the backup routes, causing AWS to prefer the primary Direct Connect routes.

3. Modify MED values: Although you currently use the same MED values, you can set a higher MED value for the backup Direct Connect. AWS will prefer routes with lower MED values.

4. Use AWS Direct Connect Gateway: This allows you to aggregate multiple Direct Connect connections and control routing preferences more granularly.

5. Monitor using CloudWatch: While not showing the exact next-hop, you can use Amazon CloudWatch to monitor the traffic flow through your Direct Connect connections. This can help you verify that traffic is flowing as expected through your primary connection.

6. Use AWS CLI or API: For more detailed routing information, you may need to use the AWS CLI or API, which can provide more in-depth data about your Direct Connect routes and preferences.

Remember, implementing these changes requires careful planning and testing to ensure your network behaves as expected. It's also advisable to work with AWS support if you need more detailed visibility into your Direct Connect routing.
Sources
AWS Direct Connect gateways - AWS Direct Connect
AWS Direct Connect gateways - AWS Direct Connect
Welcome - AWS Direct Connect