Public VIF vs Private VIF for accessing S3 for multi-accounts

Hello Mo,

Thank you for contacting us with your question.

Please find my answers below:

Q1 -

I understand the difference between a private and public VIFs for accessing S3, however, I can't really decide which to use since we have no specific requirement, but what's the purpose of still accessing the bucket via a public IP over DX since I can already do that over the public internet? Any thoughts would be appreciated please.

There are few benefits using Public VIF to access S3. They are:

1. Performance: Using Public VIF allows you to access the S3 resource via the AWS Backbone network using Direct Connect (DX). Hence, accessing the S3 resources can be more performance efficient than internet traffic.
2. Data Transfer Costs: Data transfer out of S3 to the internet is typically more expensive than data transfer out of S3 to Direct Connect. If you're transferring large amounts of data, this could lead to significant cost savings. (doc: https://aws.amazon.com/directconnect/pricing/)

Q2 -

Assuming that I choose to use private links, then a pair of VIFs would also be enought for other resources, such as EC2, to be access over DX right?

Yes - you could access your private links (VPC endpoints) over DX if the traffic is not originated from the same VPC.

Q3 -

Do I need to deploy a virtual gateway at the destination AWS account (I will be sharing our DX connections across our different AWS accounts) for both types of VIFs? or a gateway is only needed for private VIFs please?

**Approach 1 Using VIF: ** For Private VIFs:

Yes, you MUST create and attach a Virtual Private Gateway (VGW) to your VPC in the destination AWS account This is mandatory for private VIFs as they are used to connect to resources within a VPC For Public VIFs:

No, you do NOT need a Virtual Private Gateway Public VIFs connect directly to AWS public services (like S3, DynamoDB, etc.) without requiring a VGW They work similarly to how you'd access AWS public services over the internet, just over the Direct Connect connection instead

If you're sharing DX across accounts: For Private VIFs:

Create VGW in each destination account Associate VGW with the target VPC The owner of the DX connection needs to allocate/share the private VIF to the destination account The destination account needs to accept the VIF For Public VIFs:

No VGW needed Simply allocate/share the public VIF to the destination accounts The destination accounts need to accept the VIF Reference Documentation:

Working with Virtual Interfaces Direct Connect Gateway associations

Approach 2: Using DX Gateways

DXGW provides a more scalable solution, especially when dealing with:

• Multiple VPCs across different regions
• Multiple AWS accounts
• Transit Gateway integration needs

This approach allows you to have:

• One-to-many relationship
• Simpler to manage at scale
• More cost-effective when connecting to multiple VPCs
• Better region support
• Higher bandwidth aggregation

Working with Direct Connect Gateways Direct Connect Gateway associations