3.13. Transit Gateway

What is the AWS Transit Gateway (TGW)?

A network transit hub that connects VPCs and on-premises networks via site-to-site VPNs and Direct Connect.

What problem does Transit Gateway solve?

It reduces complexity in network architectures by enabling transitive routing and eliminating the need for full mesh connections.

What types of attachments can be made to a Transit Gateway?

VPC attachments, site-to-site VPN attachments, and Direct Connect Gateway attachments.

Why are full mesh architectures problematic without Transit Gateway?

They scale poorly, require many connections, and become increasingly complex to manage.

How does Transit Gateway improve hybrid connectivity for a corporate office?

It allows multiple VPN tunnels to terminate on the TGW instead of on each VPC, reducing the total number of tunnels.

Does Transit Gateway support transitive routing?

Yes, it supports transitive routing between all attached networks.

How does TGW simplify routing between VPCs?

A single TGW can route traffic between multiple VPCs through attachments, removing the need for VPC peering.

Can a Transit Gateway be peered with other TGWs?

Yes, it can be peered with other TGWs across regions and accounts.

Can Transit Gateways be shared across AWS accounts?

Yes, using AWS Resource Access Manager (RAM).

What kind of route table does Transit Gateway use by default?

A default route table to manage traffic between attachments.

Can multiple route tables be created with TGW?

Yes, to support complex routing topologies.

What AWS feature allows TGW to connect with on-premises over Direct Connect?

Transit Gateway attachments to Direct Connect Gateway.

What is a key benefit of Transit Gateway in terms of scalability?

It allows centralized, scalable, and highly available routing without the need for many individual connections.

What kind of network architecture complexity does TGW help reduce?

Complexity due to multiple VPC peerings and full mesh VPN connections.

Is cross-region peering supported by Transit Gateway?

Yes, including peering across accounts.

What is Transit Gateway?

What does the architecture look like without Transit Gateway?

What is the architecture look like with Transit Gateway?

What are some considerations for using Transit Gateway?