CloudGuild · Blog · Cheat sheets · Lessons · Certifications
AWS Transit Gateway — Centralized network routing
AWS Transit Gateway is a service that simplifies the management of multiple VPCs and on-premises networks by providing a single point of connectivity.
What it is
- A hub-and-spoke model for connecting multiple VPCs and on-premises networks.
- Acts as a central router for managing traffic between connected networks.
When I reach for it
- When you have multiple VPCs and want to reduce complexity in routing.
- For connecting on-premises networks to AWS environments seamlessly.
- When needing to manage traffic across regions or accounts efficiently.
Key architectural decisions
- Decide whether to use the default route table or create custom route tables for specific traffic flows.
- Choose between enabling VPN or AWS Direct Connect for on-premises connectivity.
- Determine whether to use resource access manager (RAM) for sharing transit gateways across accounts.
Gotchas & exam traps
- Remember that Transit Gateway has a limit on the number of attachments (50 by default, can be increased).
- Be cautious of data transfer costs between VPCs; it can add up quickly.
- Ensure that route propagation is correctly configured to avoid routing issues.
The architect view
- AWS Transit Gateway is essential for simplifying complex network architectures and enhancing operational efficiency. It allows for scalable, maintainable routing, especially in multi-VPC or hybrid environments.